48 posts · 19,219 views
Rats giggle when they’re tickled and flatworms fence with their penises. Who knew? Explore the science behind animal behavior and see where we fit in this quirky world.
Miss Behavior
48 posts
Sort by: Latest Post, Most Popular
View by: Condensed, Full
- May 15, 2013
- 09:46 AM
- 35 views
Male Black Widows Sniff Out Femme Fatales
by Miss Behavior in The Scorpion and the Frog
I am thrilled to announce that this month I am joining a new top-notch science blogging team at Scitable, Nature Education’s award-winning science education website! (But don’t worry, friends. I will continue to post here about animal physiology and behavior every Wednesday). Next week, Scitable will be launching eleven new blogs covering topics like neuroscience, genetics, oceanography, physics and more. I will be co-authoring an evolution blog called Accumulating Glitches together with Sedeer el-Showk (the author of the fantastic nature blog Inspiring Science). To celebrate the launch of these new science blogs, many of us are writing guest posts at Student Voices, another Scitable blog. What follows is the start of my guest post:__ A female western black widow contemplates the tastinessof her suitor. Photo by Davefoc at Wikimedia Commons. Sexual reproduction is a costly affair, but the costs are not usually equal for males and females. Among animals, females generally produce larger gametes (eggs are way bigger than sperm), spend more energy gestating or incubating the young before they are born, and spend more effort caring for the young after they are born. It’s no wonder then that across animal species, females are typically more choosy of who they mate with than males are. But what if the tables are turned and sex is more costly for males than it is for females? Such is often the case for black widow spiders, named for the females’ infamous reputation for making a post-coital snack of their mates. In such a situation where every sexual encounter is potentially the last, who would blame males for being more choosy of their mating partners? But are they? To find out, read the rest of the post here! And to find out more, check this out:Johnson, J., Trubl, P., Blackmore, V., & Miles, L. (2011). Male black widows court well-fed females more than starved females: silken cues indicate sexual cannibalism risk Animal Behaviour, 82 (2), 383-390 DOI: 10.1016/j.anbehav.2011.05.018 ... Read more »
Johnson, J., Trubl, P., Blackmore, V., & Miles, L. (2011) Male black widows court well-fed females more than starved females: silken cues indicate sexual cannibalism risk. Animal Behaviour, 82(2), 383-390. DOI: 10.1016/j.anbehav.2011.05.018
- May 8, 2013
- 09:50 AM
- 52 views
Thanks Mom!
by Miss Behavior in The Scorpion and the Frog
Like Mother, like baby! Photo from freedigitalphotos.net.Moms give us so much more than we ever give them credit for. Biologically speaking, we all have a mom and a dad (unless you’re a flatworm or some other species that can reproduce without sex) that provide us with one of each chromosome type (our chromosomes contain our genes, commonly thought of as our “biological blueprints”). So it makes sense that we tend to think of ourselves as being half-our-mom and half-our-dad. But not so! All of us are slightly more-our-mom and slightly less-our dad.Our genes are encoded in our DNA, which is coiled and tightly packed into dense little chromosomes. Most of our cells contain 23 different pairs of chromosomes (for a total of 46), and one from each pair comes from each parent. One of those pairs is the sex chromosomes. Individuals with two X sex chromosomes are genetically females and individuals with an X and a Y sex chromosome are genetically male. Because genetic males are the only ones with Y chromosomes, all Y chromosomes are inherited from dad. But compared to X chromosomes, Y chromosomes are piddly little things that don’t contain as many genes. So if you’re a guy, you already have more genes from mom than from dad.In addition to our 46 chromosomes that we keep in the nucleus of each cell, we also have a tiny set of genes in another cell structure, the mitochondria. This mitochondrial DNA is only inherited from the mother, so regardless of whether you are XX or XY, you have a few more genes from mom than from dad.Wait! My genes are where?? Your genes are lined up on the doubled-stranded DNA, which is tightly coiled and packed into chromosomes. You have 23 different pairs of chromosomes, where one of each pair came from mom and the other came from dad. A copy of each of these 23 pairs of chromosomes (46 chromosomes in total) is in the nucleus of every cell you have (except for sperm or egg cells, which only have one of each pair, or 23 chromosomes in total). Get it? Figure adapted from an image by KES47 at Wikimedia.But we are not simply a product of our genes. If we were, identical twins would be, well… identical. But they’re not. The slight differences between twins results from differences in how our environment interacts with our genes. (By environment, I’m not just talking about temperature and air quality, but rather all external influences). Our environment plays a big role in shaping the individuals we become, and our mothers have more effect on our environment than our fathers do. When we are developing in the womb, our moms’ bodies single-handedly provide us with nutrients, hormones, and antibodies (and sometimes pathogens). During this time, her circumstances and decisions will determine what kind of setting we are born into. After we’re born, the social interaction, nutrition, and antibodies (through breast feeding and/or vaccines) she provides will all influence our gene activity and thus how we develop. Collectively, the traits that we develop due to these factors and all mom’s other nongenetic influences are called maternal effects.Mom gives us more genes, and has more input in determining how active each gene is. In the end, we are who we are in large part because of our moms.So Mom, this is for you: Happy (early) Mother’s Day! Want to know more? Check these out:1. BERNARDO, J. (1996). Maternal Effects in Animal Ecology Integrative and Comparative Biology, 36 (2), 83-105 DOI: 10.1093/icb/36.2.832. Wolf, J., & Wade, M.J. (2009). What are maternal effects (and what are they not)? Phil. Trans. R. Soc. B, 364, 1107-1115 ... Read more »
BERNARDO, J. (1996) Maternal Effects in Animal Ecology. Integrative and Comparative Biology, 36(2), 83-105. DOI: 10.1093/icb/36.2.83
Wolf, J., & Wade, M.J. (2009) What are maternal effects (and what are they not)?. Phil. Trans. R. Soc. B, 1107-1115. info:/
- May 1, 2013
- 09:27 AM
- 78 views
The Craptastic Conversations of the Black Rhinoceros
by Miss Behavior in The Scorpion and the Frog
What are you saying with your smells? Image by freedigitalphotos.net.Animals communicate in all kinds of ways: with vocalizations, body language, vibrations, and even odors. In fact, compared to most species, we are pathetic in our abilities to communicate with body odor. With just a whiff of eau de crotch, many animals can decipher that individual’s species, sex, age, health status, reproductive status, emotional state, and dietary history. Some species can go so far as to make out that individual’s exact identity (*Sniff Sniff* Oh! Hi Mike!).There are a lot of advantages to using odors to communicate. For one thing, messages sent by smell are more likely to be honest than messages sent by other means. (You might be able to do a pretty good Shakira impersonation, but you can’t hide the fact that you had a tuna sandwich for lunch and haven’t brushed your teeth since). Another advantage is that unlike other signal types, an odor signal can be left behind, kind of like those sticky-notes you leave on your food in the fridge.How do scientists know which species use odors to communicate and what information these signals contain? This investigatory process involves a lot of reasoning.A solitary black rhino. Photo by John and Karen Hollingsworth at the US Fish and Wildlife Service.Wayne Linklater, Katha Mayer and Ron Swaisgood, an international team of researchers associated with Victoria University of Wellington in New Zealand, Nelson Mandela Metropolitan University in South Africa, University of Potsdam in Germany, and the San Diego Zoo Institute for Conservation Research in California, set out to test whether black rhinoceros use odor to communicate. Although rhinos lack the specialized scent glands that many smell-communicating species have, there are many reasons to suggest that they are a likely species to communicate this way. A photo of field assistant Brayden Crocker with rhino dung scrape mark. Photo by Wayne Linklater.Black rhinos are solitary. Females often have overlapping ranges, but males’ territories only overlap at their boundaries. This means that they would rarely encounter one another and would benefit from a means to leave “sticky-notes” behind to indicate where their territories are. Furthermore, despite their poor eyesight, male black rhinos have a poop-ritual in which they scrape at the ground and spread their dung. Although female rhinos don’t spread their poo, they do spray their pee when they are ready to mate. Between 2004 and 2006, the Ezemvelo KwaZulu-Natal Wildlife Veterinary and Game-Capture Team captured a number of black rhinoceros from the Ezemvelo KwaZulu-Natal Wildlife Reserves in South Africa in order to relocate them to other reserves for conservation purposes. At this time, Wayne, Katha, and Ron collected dung from rhinos with known sexes and ages. They stored the dung in labeled plastic bags and froze them to preserve the odor freshness for a series of experiments to explore the extent of the black rhinos’ abilities to communicate with their bodily waste. In one experiment, the researchers asked whether black rhinos could differentiate between the dung of males and females and between the dung of adults and immature subadults. They presented rhinos with the dung of young males, young females, adult males and adult females, and then measured how many times they sniffed each and how long they spent sniffing. The rhinos spent more time sniffing male dung than female dung. This means that rhino poop likely communicates the sex of the pooper. Rhinos also responded differently to adult and subadult poop, suggesting that they can tell whether the pooper is an adult or not.In order to test whether rhinos may be able to tell the individual identity of the pooper, they did a habituation-dishabituation test. Habituation is when an animal gets used to something that happens repeatedly and stops responding to it. For example, the first time you heard Gangnam Style, you probably stopped what you were doing and maybe even learned the dance. But now it has been so ridiculously over-played that when you hear it, you just ignore it. Dishabituation happens when an animal is exposed to something slightly different and has a heightened response again. Kind of like the excitement over Psy’s new song, Gentleman, even though it sucks. A photo of rhino performing flehmen, a behavior that helps waft odors for better odor detection. Photo by Wayne Linklater.Wayne, Katha, and Ron exposed rhinos to the same individual’s dung three times to see if their interest in it waned. With each presentation, the rhinos spent a little less time sniffing it. When the researchers put poop from a different rhino (that was the same sex and age as the first pooper) in front of them, their interest returned. This suggests that rhinos can tell the individual identity of the pooper from his/her poop.But can rhinos use their poop like “sticky-notes”? The researchers aged dung for 1, 4, 16 and 32 days and put them in front of rhinos to smell. Their response was the same, no matter how old the dung was. This indicates that rhinos can spread their poop to leave an “I was here” message for at least a month.As fun as it may be to spend years studying rhinoceros poop, there are some important uses for research like this. Black rhinos are critically endangered, largely due to hunting, poaching and habitat loss. In fact, Mozambique's Limpopo National Park declared the last of their rhino population killed as recently as last month. Conservation efforts such as captive breeding programs and reintroductions have helped in several areas, but have not been enough to sustain the populations. Conservationists could apply this knowledge of how rhinoceros use dung odors to communicate to these breeding and reintroduction efforts in order to make them considerably more successful. Wa... Read more »
Linklater, W., Mayer, K., & Swaisgood, R. (2013) Chemical signals of age, sex and identity in black rhinoceros. Animal Behaviour, 85(3), 671-677. DOI: 10.1016/j.anbehav.2012.12.034
- April 10, 2013
- 09:40 AM
- 116 views
Not Quite Like a Rolling Stone
by Miss Behavior in The Scorpion and the Frog
Dung beetles are competitive little critters. And who can blame them? When a fresh pile of poo is at stake, wouldn’t we all be a bit competitive? …Okay, maybe not. But animal dung is actually chock-full of nutrients, which makes it a precious resource to the animals that can make use of them. The approximately 6,000 species of dung beetles and their babies are among the animals that make excellent use of those resources.Mmmm... A poo-pile worth fighting for! Image by Duwwel at Wikimedia.But even animal dung is a limited resource. When it is plopped out, dung beetles gather from far and wide (okay, maybe not that far) to compete over the miraculous manna from heaven. Many dung beetle species, such as the South African dung beetle, forms round balls of poo to prepare them for transport, and then rolls them away from the poo-pile. This process of forming the poo-ball and getting it away from the poo-pile must be quick. Otherwise, dung beetles that are either less fortunate or less-inclined to work for their poo-balls will try to steal pre-made poo-balls from those that worked to form them.But this isn’t a story about competition. This is a story about navigation.The fastest way to get a poo-ball away from the poo-pile is in a straight line, and dung beetles are experts at pushing their poo-balls in straight lines. Researchers have played countless tricks (like adding obstacles and spinning floors) on these guys to try to confuse them into going the wrong way, but to no avail. These guys always seem to know where they want to go. But how?There are many methods animals use to navigate. Some use celestial cues, like the placement of the sun or the stars, to know what direction they are facing. Some remember the placement of landmarks in places they visit often, such as their home. But many combine strategies to get a more accurate idea of where they are going.Marie Dacke and Marcus Byrne from the University of the Witwatersrand in South Africa, and Jochen Smolka, Eric Warrant, and Emily Baird from Lund University in Sweden set out to test the relative importance of landmarks and celestial cues in South African dung beetles. A dung beetle rolls his poo-ball backwards. Photo by Dewet at Wikimedia.South African dung beetles face backwards when they roll their poo-ball away from the poo-pile. In this position, they should always be able to see the poo-pile and perhaps use the pile itself as a landmark. To test this, the researchers placed beetles on dung piles and waited for them to make a poo-ball and roll it away. Once they got 75 cm away, they moved the dung pile 45° to the left or to the right with respect to the beetle. If the beetles use the dung pile as a landmark, the new location of the pile should make the beetles change course by 45° as well. But they didn’t. Next, the researchers tested whether dung beetles rely on more distant landmarks to know where they’re going. They created two adjacent, but different, testing arenas: One had an unobstructed view of the surrounding landscape (called the “landmark arena”), and the other was surrounded by a beige featureless wall (called the “no-landmark arena”). Both arenas had a full view of the sky and its celestial cues. They placed beetles and their poo-balls at the center of the landmark arena and allowed them to roll away at least 80 cm. Then they picked them up and placed them in the no-landmark arena and waited to see if the removal of landmarks caused them to roll in the same direction or change bearings. They repeated this in the opposite direction to see if the addition of landmarks could improve accuracy. To check if simply moving the beetles affected their rolling directions, they also picked beetles up and returned them to their original arenas (these were the control beetles). In the end, the beetles that changed arenas did not navigate any differently than the beetles that were picked up and returned to their original arenas, indicating that as long as the beetles can see the sky, they don’t seem to rely on landmarks to navigate.To test if the sky provides important navigational information to the dung beetles, the researchers put little cardboard hats on some of them to block their view of the sky and had them roll their poo-balls from the center of a wall-free arena with full view of landmarks. Other beetles were allowed to roll their poo-balls without the obstructive hats. But just to be sure the hats themselves weren’t causing the beetles trouble (other than by blocking their view of the sky), the researchers also tested a group with transparent plastic hats. They found that the beetles with no hats or with clear hats rolled their poo-balls just fine. However, the beetles with dark cardboard hats spun in circles, whirled and twirled, apparently having the darnedest time going in a straight line. But a dung beetle doesn’t have to wear a cardboard hat to lose track of the sky. The researchers tested beetles on a clear day with hats, on a clear day without hats, and on an overcast day without hats. The overcast sky screwed up the little buggers almost as much as the cardboard hats did!Combined, these studies show that the South African dung beetles rely almost entirely on celestial cues and don’t seem to rely on landmarks at all. Even the dung pile, which is always a large, central easy-to-see landmark, seems to be completely ignored by the poo-rolling dung beetles. This heavy reliance on a single type of navigational cue is unusual in the animal world, and you can imagine the havoc it would wreck if all animals got so lost every time there was a cloudy day. But for the South African dung beetle, the consequences aren’t as high as they are for other species. They aren’t taking their poo-balls to a specific location, just away quickly, so they’re never truly lost as long as they’re with their poo. And if the worst happens and someone takes their poo-ball, they can go make another.We can learn a lot from these guys. In life we face obstacles, we go unknown directions, and we get lost. But no worries… The sun will come out again soon.Want to know more? Check these out:Dacke M, Byrne M, Smolka J, Warrant E, & Baird E (2013). Dung beetles ignore landmarks for straight-line orientation. Journal of comparative physiology. A, Neuroet... Read more »
Dacke M, Byrne M, Smolka J, Warrant E, & Baird E. (2013) Dung beetles ignore landmarks for straight-line orientation. Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, 199(1), 17-23. PMID: 23076443
- April 3, 2013
- 10:53 AM
- 132 views
Risky Business: Ape Style
by Miss Behavior in The Scorpion and the Frog
The decisions of this chimpanzee living in the Tchimpounga Chimpanzee Sanctuary are affected by his social situation. Photo by Alex Rosati.If you have a choice between a prize that is awesome half the time and totally lame the other half of the time or a mediocre prize that is a sure-thing, which would you choose? Your choice probably depends on your personality somewhat. It may also depend on your needs and your mood. And it can depend on social contexts, like if you’re competing with someone or if you’re being watched by your boss or someone you have a crush on.All animals have to make choices. Some choices are obvious: Choose the thing that is known to be of high quality over the thing that is known to be of low quality. But usually, the qualities of some options are uncertain and choosing them can be risky. As with us, the likelihood of some primates, birds, and insects to choose riskier options over safer ones can be affected by outside influences. And we aren’t the only species to have our risk-taking choices influenced by social context. Anthropologists Alex Rosati and Brian Hare at Duke University tested two ape species, chimpanzees and bonobos, in their willingness to choose the riskier option in different social situations. They tested chimpanzees living in the Tchimpounga Chimpanzee Sanctuary and bonobos in the Lola ya Bonobo Sanctuary, both in the Democratic Republic of Congo. Most of the apes living in these sanctuaries are confiscated from poachers that captured them from the wild for the pet trade and for bushmeat. In these sanctuaries the animals live in social groups, generally spending their days roaming large tracts of tropical forest and their nights in indoor dormitories. This lifestyle rehabilitates their bodies and minds, resulting in psychologically healthy sanctuary inhabitants.It is in these familiar dormitories that Alex and Brian tested the apes’ propensity for making risky choices. For their experimental set-up, an experimenter sat across a table from an ape and offered them two options: an overturned bowl that always covered a treat that the apes kinda like (peanuts) versus an overturned bowl that covered either an awesome treat (banana or apple) or a lousy treat (cucumber or lettuce). In this paradigm, the peanut-bowl represents the safe choice because whenever the ape chooses it, they know they’re getting peanuts. But the other bowl is the risky choice, because half the time they get fruit (yum!), but the other half of the time they get greens (bummer).This figure from Rosati and Hare's 2012 Animal Behavour paper shows Alex demonstrating the steps they would go through before the ape chose one of the two options.After spending some time training the apes to be sure they understood the game, the researchers tested their choices in different social situations. In each test session, the ape was allowed to choose between the two bowls (and eat the reward) multiple times (each choice was called a trial). But before the test session began and in between choice trials, another experimenter sat with the ape for two minutes and did one of three things: In one group, the experimenter sat at the table and silently looked down (they called this the “neutral condition”). In another group, the experimenter repeatedly offered the ape a large piece of food, pulling it away and grunting whenever the ape reached for it (they called this the “competitive condition”). In a third group, the experimenter tickled and played with the ape (they called this the “play condition”).Alex and Brian found out that whereas bonobos chose the safe option and the risky option about equally, the chimpanzees were significantly more likely to choose the risky option. But despite this species difference, both species chose the risky option more often in the “competitive condition”. Neither species increased their risk-taking in the “play condition”.The graph on the left shows that wheras bonobos chose the safe option and the risky option each about 50% of the time (where the dashed line is), the chimpanzees chose the risky option much more often. The graph on the right shows that both species chose the risky option more often in the "competition condition" than they did in the "neutral condition". Figure from Rosati and Hare's 2012 Animal Behavour paper.These are interesting findings, especially when you consider the natural behaviors and lifestyles of these closely related species. Bonobos can be thought of as the hippies of the ape world, happily sharing and using sex to settle disputes and strengthen relationships. In comparison, chimpanzees are more like gangsters, aggressively fighting over resources and dominance ranks. So in general, the more competitive species is more likely to take risks. But when the social environment becomes more competitive, both species up the ante. This effect doesn’t seem to be simply the result of being in a social situation, because the apes didn’t increase their risk-taking in the presence of a playful experimenter. This still leaves us with some questions to ponder though. Are apes more likely to take risks when an experimenter is offering food and taking it away because of a heightened sense of competition, or is this the result of frustration? And would we see the same effect if the “competitor” were another ape of the same species, rather than a human experimenter? How would their behavior change if they were hungry? These questions are harder to get at, but this research does demonstrate that like in humans, the decision-making process in chimpanzees and bonobos is dependent on social context. Want to know more? Check this out:Rosati, A., & Hare, B. (2012). Decision making across social contexts: competition increases preferences for risk in chimpanzees and bonobos Animal Behaviour, 84 (4), 869-879 DOI: 10.1016/j.anbehav.2012.07.010 ... Read more »
Rosati, A., & Hare, B. (2012) Decision making across social contexts: competition increases preferences for risk in chimpanzees and bonobos. Animal Behaviour, 84(4), 869-879. DOI: 10.1016/j.anbehav.2012.07.010
- March 6, 2013
- 11:20 AM
- 181 views
Hey Hey! We’re The Monkeys!
by Miss Behavior in The Scorpion and the Frog
A tamarin rock star (photographed by Ltshears at Wikimedia)Our moods change when we hear music, but not all music affects us the same way. Slow, soft, higher-pitched, melodic songs soothe us; upbeat classical music makes us more alert and active; and fast, harsh, lower-pitched, dissonant music can rev us up and stress us out. Why would certain sounds affect us in specific emotional ways? One possibility is because of an overlap between how we perceive music and how we perceive human voice. Across human languages, people talk to their babies in slower, softer, higher-pitched voices than they speak to adults. And when we’re angry, we belt out low-pitched growly tones. The specific vocal attributes that we use in different emotional contexts are specific to our species… So what makes us so egocentric to think that other species might respond to our music in the same ways that we do?A serene tamarin ponders where he placed his smoking jacket (photographed by Michael Gäbler at Wikimedia)Chuck Snowdon, a psychologist and animal behaviorist at the University of Wisconsin in Madison, and David Teie, a musician at the University of Maryland in College Park, teamed up to ask whether animals might respond more strongly to music if it were made specifically for them. Cotton-top tamarins are squirrel-sized monkeys from northern Colombia that are highly social and vocal. As in humans (and pretty much every other vocalizing species studied), they tend to make higher-pitched tonal sounds when in friendly states and lower-pitched growly sounds when in aggressive states. But tamarin vocalizations have different tempos and pitch ranges than our tempos and pitch ranges.Chuck and David musically analyzed recorded tamarin calls to determine the common attributes of the sounds they make when they are feeling friendly or when they are aggressive or fearful. Then they composed music based on these attributes, essentially creating tamarin happy-music and tamarin death metal. They also composed original music based on human vocal attributes. They played 30-second clips of these different music types to pairs of tamarins and measured their behavior while the song was being played and for the first 5 minutes after it had finished. They compared these behavioral measures to the tamarins’ behavior during baseline periods (time periods not associated with the music sessions).An example of happy tamarin music (Copyright by David Teie and available through Biology Letters) can be found here.An example of aggressive tamarin music (Copyright by David Teie and available through Biology Letters) can be found here.As the researchers had predicted, tamarins were much more affected by tamarin music than by human music. Happy tamarin music seemed to calm them, causing the tamarins to move less and eat and drink more in the 5 minutes after the music stopped. Compared to the happy tamarin music, the aggressive tamarin music seemed to stress them out, causing the tamarins to move more and show more anxious behaviors (like bristling their fur and peeing) after the music stopped. The tamarins also showed lesser reactions to the human music. They showed less anxious behavior after the happy human music played and moved less after the aggressive human music played. So, human voice-based music also affected the tamarins to some degree, but not as strongly. This may be because there are some aspects of how we communicate emotions with our voice that are the same in tamarins. (How did the tamarin music make you feel?) Can you imagine what we could do with this idea of species-specific music? Well, David and Chuck did! They have since developed music for cats using similar techniques. Although they're still working on the paper, they have said that the cats prefered and were more calmed by cat music compared to human music. You can find samples and get your own copies here. We often think of vocal signals conveying messages in particular sounds, like words and sentences. But calls seem to do much more than that, making the emotions and behaviors of those listening resemble the emotions of those calling.Want to know more? Check this out:Snowdon, C., & Teie, D. (2009). Affective responses in tamarins elicited by species-specific music Biology Letters, 6 (1), 30-32 DOI: 10.1098/rsbl.2009.0593... Read more »
Snowdon, C., & Teie, D. (2009) Affective responses in tamarins elicited by species-specific music. Biology Letters, 6(1), 30-32. DOI: 10.1098/rsbl.2009.0593
- February 20, 2013
- 01:14 PM
- 178 views
Did that Rock Just Ink on Me? (A Guest Post)
by Miss Behavior in The Scorpion and the Frog
By Sam Brunner and Ian Straus Cephalopods, like octopuses, squid, and cuttlefish, are well known for their ability to alter the color and patterns on their bodies for better camouflage, mimicry, and even communication. By developing a unique set of camouflage tools, cephalopods excel at not being seen or being seen but not detected as a cephalopod. There are videos all over the internet showcasing how squid can terrify divers with their flashing red displays, or how some octopuses avoid their predators by mimicking the local venomous snakes. This video provides the perfect example of an octopus using its incredible camouflage to become invisible while convincing you it is merely a clump of algae. You see, where many animals have lowly organelles in their skin cells responsible for pigments, cephalopods are unique in having a whole organ dedicated to this task. They’re called chromatophores. Each chromatophore is made up of colored pigment granules held in the ever so eloquently named cytoelastic sacculus, which is surrounded by 15 to 25 radially arranged muscle cells (like spokes on a wheel). Each muscle cell is also associated with a neural axon and its supportive glial cells, which puts it under the control of the nervous system. Image created by Ian Straus.So, when an octopus wants to change color, a signal travels from the brain and down the neural axon to the chromatophore, telling the muscles to contract. The muscle contraction pulls on the pigment-filled sac, stretching it to change its translucence and thereby changing the amount of color showing through. The chromatophores can produce yellow, orange, red, brown, and occasionally black pigments. The intensity of the color depends on how many muscle fibers are contracted, and therefore how much the sac expands and the pigment is spread out. Once a chromatophore develops, it will stay put for the rest of the animal’s life. As the animal grows, new, smaller chromatophores develop in the spaces between the old ones. These new organs are only able to produce yellow pigment at first, but darken as they get older. Dieter Froesch of the Zoological Station of Naples conducted an experiment using the common octopus (Octopus vulgaris) to determine which of their nerves control the chromatophore organs in each part of the body. Each octopus examined was anaesthetized, had a nerve cut and was then checked a few days later for the results. Froesch found that of the thirty nerves leaving the brain of O. vulgaris, ten have control over chromatophores, with each nerve controlling a different region of the body. These regions have well defined borders with no overlap. The head region alone is controlled by five different nerves, especially around the eyes. This suggests that fine control over color patterns around the eye may play an important role in effective camouflage. Furthermore, the coloration and chromatophores in one area of the body, the funnel, didn’t appear to be controlled by any of the nerves cut in this experiment. This image shows the different chromatophore regions that each nerve controls. The funnel, which does not have nerve-controlled chromatophores, is the tube near the eye. Image is from Froesch’s Marine Biology paper (1973).In most cephalopods, vision is the most important sense. Information about their surroundings is processed in vision regions of the brain, which then send along information to chromatophore regions of the brain. The chromatophore brain regions, which contain motor neurons, send signals to the chromatophores throughout the body telling them to contract. So, if an octopus sees a bright orange coral structure, the chromatophores will contract in a way that results in bright orange skin being displayed. The vision-chromatophore pathway may be the most important part of cephalopod camouflage, but it isn’t the only set of structures that play a role. Leucophores allow for white pigment and reflective iridophores are responsible for blues and greens. Cuttlefish and many octopuses also have muscles throughout the skin arranged into papillae, which can form bumps or spikes that transform the texture of the animal into that of seaweed or an inconspicuous rock. In Octopus vulgaris, all these components are arranged into 1 mm wide units distributed across the skin, with the leucophores and iridophores in the central region, papillae at the exact center, and chromatophores distributed throughout. This complex physiological system grants cephalopods the greatest array of possible camouflages and firmly positions them as the coolest of the invertebrates.Want to know more? Check these out: 1. Froesch, D. (1973). Projection of chromatophore nerves on the body surface of Octopus vulgaris Marine Biology, 19 (2), 153-155 DOI: 10.1007/BF003535862. Messenger JB (2001). Cephalopod chromatophores: neurobiology and natural history. Biological reviews of the Cambridge Philosophical Society, 76 (4), 473-528 PMID: 11762491... Read more »
Froesch, D. (1973) Projection of chromatophore nerves on the body surface of Octopus vulgaris. Marine Biology, 19(2), 153-155. DOI: 10.1007/BF00353586
Messenger JB. (2001) Cephalopod chromatophores: neurobiology and natural history. Biological reviews of the Cambridge Philosophical Society, 76(4), 473-528. PMID: 11762491
- February 13, 2013
- 11:32 AM
- 237 views
Friends Without Benefits: A Guest Post
by Miss Behavior in The Scorpion and the Frog
By Joseph McDonaldDo you want to avoid the friend zone? Photo by freedigitalphotos.net.Guys DREAD the friend zone. That heart-aching moment when the girl you’ve been fawning over for years says you’re the best listener, the sister she never had, or so much better than a diary! You’ve been so nice to her and her friends, listening to all their drama. But that’s just the problem... you’re too nice to too many people. Research performed by Aaron Lukaszewski and Jim Roney at the University of California – Santa Barbara (UCSB) tested whether preferences for personality traits were dependent on who the target was. In Experiment 1, they asked UCSB undergrads, on a scale from 1 to 7, the degree to which their ideal partner would display certain traits towards them and towards others. These traits included synonyms for kindness (e.g. affectionate, considerate, generous, etc.), trustworthiness (committed, dependable, devoted, etc.), and dominance (aggressive, brave, bold, etc.). Experiment 2 replicated the procedures of Experiment 1. The only difference was that the term “others” was divided into subsets including unspecified, family/friends, opposite sex non-family/friend, and same-sex non-family/friend. Let’s go over the do’s and don’ts so that future “nice guys” aren’t friend zoned. According to the findings, as graphed below: Figure from Aaron and Jim's 2010 Evolution and Human Behavior paper.1. Women generally prefer men who are kind and trustworthy. So, to get that girl, don’t be mean; that’s not the point. This isn’t 3rd grade so don’t pull her hair and expect her to know that you LIKE-like her. 2. Women prefer men who are kinder and more trustworthy towards them than anyone else. So it’s not so much whether you are nice enough, its whether she knows you are nicer to her than anyone else. 3. Women prefer men who display similar amounts of dominance as they do kindness. Dominance isn’t a bad thing, as long as you can distinguish her friends from her foes; especially her male friends. 4. To make things more complicated, women also prefer men who are directly dominant toward other men but don’t display dominance toward them or their family/friends, whether male or female. Some guys may want to befriend these other men, but be weary. Women preferred dominance over kindness in this situation, so kindness may not be enough. These preferences may have developed to avoid mating with someone willing to expend physical and material resources for extramarital relationships, and invest greater in her and the children. Moderate kindness and trustworthiness toward others will maintain social relationships and prevent detrimental relationships, which may be why women generally prefer kind and trustworthy guys. But in all fairness, women can be in the friend zone too; just look at Deenah and Vinny (excuse the shameful Jersey Shore reference). There are some things that guys look for in a mate, so ladies, here is a little advice: 1. Guys generally want a mate who is kind and trustworthy, too. We’re not that different; so don’t act a little crazy because you think he likes it. He doesn’t. 2. Guys also prefer women who display dominance toward other women (non- family/friend). Don’t be afraid to put that random girl with the prying eyes in her place. Contrary to the hypotheses predicting female mate preferences, male mate preferences may have developed as a way to take advantage of strong female-based social hierarchies. No matter what the reasoning, however, if you can 1) be kinder and more trustworthy towards that special someone than anyone else and 2) display dominance over other same-sex people, then feel free to say good-bye to the friend zone! For further details, check out the original experiment: Lukaszewski, A., & Roney, J. (2010). Kind toward whom? Mate preferences for personality traits are target specific Evolution and Human Behavior, 31 (1), 29-38 DOI: 10.1016/j.evolhumbehav.2009.06.008 ... Read more »
Lukaszewski, A., & Roney, J. (2010) Kind toward whom? Mate preferences for personality traits are target specific. Evolution and Human Behavior, 31(1), 29-38. DOI: 10.1016/j.evolhumbehav.2009.06.008
- February 6, 2013
- 10:21 AM
- 290 views
Birds, Vitamin E, and the Race Against Time: A Guest Post
by Miss Behavior in The Scorpion and the Frog
By Alyssa DeRubeis The long and tapered wings on this young Peregrine Falcon means it was built for some serious speed! Photo by Alyssa DeRubeis.Maybe you’ve been put under the false assumption that humans are cool. Don’t get me wrong; our bodies can do some pretty neat physiological stuff. But I’m gonna burst your bubble: humans are lame. Just think of how fast we can run compared to a Peregrine Falcon in a full stoop: 27 MPH versus 242 MPH. Keep thinking about all the cool things birds can do. It doesn’t take us long to realize that our feathered friends are vastly more fascinating compared to humans. Now that you’re finally admitting defeat, I ask that you read on. The most amazing avian physiological feat is the ability to travel long distances seasonally (a.k.a migrate). Between poor weather conditions, preventing fat loss, and staying alert, migration is not easy by any means. However, birds can cope with all of these things by assimilating and using antioxidants like vitamin E. Here’s a classic bird migration scene: thousands of Tundra Swans, geese, and ducks congregate on the Mississippi River in Minnesota. Here, they rest and refuel before continuing their journey south. Photo by Alyssa DeRubeis. Let’s talk a little bit about bird migration. It’s a two-way street, where a migratory bird will (usually) fly north as soon as possible to rear its young, and then fly south where it can stay warm and eat all sorts of goodies. During these two bouts of intense exercise, the birds produce free radicals, which are types of atoms, molecules, and ions that can harm DNA and other important stuff inside the body. This is where vitamin E comes in to save the day, because this vitamin, along with vitamin A and carotenoids, are antioxidants. They drive away bad things like free radicals from birds’ bodies; some scientists suggest that they may even reduce risks of cancer! In the case of migrating birds, antioxidants can make this migration headache a lot more bearable. Well, that’s great. But where do these antioxidants come from? The short answer is avian nom-noms, but it’s one thing to eat something with an antioxidant in it. It’s quite another to actually be able to assimilate and use this antioxidant. Okay…so where do the birds get this ability from? It’s parentals!Anders Møller from the University of Paris-Sud, along with his international team including Clotilde Biard (France), Filiz Karadas (Turkey), Diego Rubolini (Italy), Nicola Saino (Italy), and Peter Surai (Scotland), pointed out that there is little research looking at maternal effects on our feathered friends. Møller hypothesized that maternal effects (the direct effects a mother has on her offspring) play a critical role in migration: If mothers put a lot of antioxidants in their eggs, the chicks will be able to absorb antioxidants better later in life. This would give these birds a competitive edge because they will migrate in a healthier condition and arrive to breeding grounds earlier.This male Barn Swallow on the left must’ve gotten back pretty early for him to have landed himself such a beautiful female. Thank you, Vitamin E! Photo by Alyssa DeRubeis. In the early 2000s, Møller and his five colleagues collected 93 bird species’ eggs. The crew was able to analyze how the natural differences in antioxidant concentrations (put in by the mother) related to the birds’ spring arrival dates in 14 of them. They found that vitamin E concentration, but not vitamin A concentration, was a reliable predictor of earlier arrival dates. This European posse took it a step further by injecting over 700 barn swallow eggs with either a large dose of vitamin E or a dose of corn oil (which contains a small amount of vitamin E). It was soon evident that the chicks with more vitamin E were bigger than chicks that received less vitamin E, thus already giving the big chicks a competitive edge over their less vitamin E-affiliated brethren. The researchers kept track of the eggs that hatched out as males in the following spring via frequent mist-netting sessions (a bird-capturing technique). Guess what? The fellas with higher vitamin E concentrations arrived earlier on average by ten days than those with lower concentrations! Sweet. But what does it all mean? First off, vitamin E is crucial for migratory birds because it allows them to process antioxidants more efficiently. In fact, another study done by Møller, Filiz Karadas, and Johannes Emitzoe out of University of Paris-Sud suggested that birds killed by feral cats had less vitamin E than birds that died of other reasons. Furthermore, the early birds get the worm. Events such as insect hatches—vital for baby birds—now occur earlier in the spring as temperatures rise (read: climate change). Plus, if you’re a male arriving at the breeding grounds early, you get to pick the best spots to raise your offspring. Wood-warblers, such as this Palm Warbler, must get back to their northerly breeding grounds in a timely fashion in order to hit the insect hatch for da babies. Photo by Alyssa DeRubeis. Obviously, there’s an advantage to up the vitamin E intake and get a head start as a developing embryo. In an egg, most nutrients come from the yolk…which comes from the mother. The healthier the mother, the more vitamin E she will put in her eggs. And vitamin E isn’t produced internally; birds must consume it. While Møller’s paper on maternal effects states that vitamin E can be found widely in nature, a separate study found no apparent association between vitamin E and avian diet. Hmm. So then where DO birds get vitamin E from? Is it a limiting resource? Is there competition for it?Clearly, we’ve got some questions and answers. As the field of “birdology,” advances, we will learn more and keep humans jealous of birds for years to come. REFERENCES1. Møller, A., Biard, C., Karadas, F., Rubolini, D., Saino, N., & Surai, P. (2011). Maternal effects and changing phenology of bird migration Climate Research, 49 (3), 201-210 DOI: 10.3354/cr010302. ... Read more »
Møller, A., Biard, C., Karadas, F., Rubolini, D., Saino, N., & Surai, P. (2011) Maternal effects and changing phenology of bird migration. Climate Research, 49(3), 201-210. DOI: 10.3354/cr01030
Møller AP, Erritzøe J, & Karadas F. (2010) Levels of antioxidants in rural and urban birds and their consequences. Oecologia, 163(1), 35-45. PMID: 20012100
Cohen, A., McGraw, K., & Robinson, W. (2009) Serum antioxidant levels in wild birds vary in relation to diet, season, life history strategy, and species. Oecologia, 161(4), 673-683. DOI: 10.1007/s00442-009-1423-9
- January 30, 2013
- 01:55 PM
- 313 views
Origins of The Scorpion and The Frog and the Social Brain
by Miss Behavior in The Scorpion and the Frog
Starting a weekly journalistic-type blog is a daunting task, especially for someone who is holding down other jobs (as most bloggers do). But I can't be happier that I started down this path in order to share with you all these wonderfully quirky stories of animal behavior and physiology. This week, I am happy to announce that The Scorpion and the Frog turns 1! It has been a remarkable first year: We've covered topics from whale dialects, to birds that kill their "siblings", to steroids and dominance in rodents; We've learned more about the researchers that contribute this fascinating knowledge to our global society; We've had fantastic guest posts by student guest writers; We've been recognized in other blogs and with awards; But my favorite aspect of this endeavor is that we are developing a growing community of readers and animal enthusiasts from all backgrounds. So today, I would like to reflect back on how we began a year ago with a repost of the very first The Scorpion and the Frog post, The Same Clay. The Same Clay According to a Hopi creation myth, the world was once nothing but water and dry land. The Sun, in his daily travels across the dry land, noticed that he had not seen a single living being. The Sun mentioned this observation to Hurúing Wuhti of the east and Hurúing Wuhti of the west, the deities of all hard substances, and they decided they would make a little bird. Hurúing Wuhti of the east made a wren out of clay and covered it with a piece of native cloth. The deities then sang a song over it and the wren came to life. They sent the wren to fly all over the earth to search for anything living, which it did. When the wren returned and reported that no living being existed anywhere, Hurúing Wuhti of the west shaped the clay to form all kinds of birds and placed these clay birds under the native cloth. The deities sang over the clay birds, bringing them to life, and they taught each of them what sounds they should make and sent them to populate the earth. Hurúing Wuhti of the west then shaped the clay to form all kinds of other animals and placed these clay animals under the native cloth. The deities sang over the clay animals, bringing them to life, and they taught them each what sounds they should make and sent them to populate the earth. Hurúing Wuhti of the east then shaped the clay to form a woman and a man and placed these people under the native cloth. The deities brought them to life with their song, and they taught them language and sent them to populate the earth. I like this myth; in particular because it illustrates that despite the awesome diversity of the animals on our planet, we are all made of the same stuff and share many similarities. At first glance, we may be amazed by eels that resist eating prey fish who are providing a dental cleaning service (like the one on the left), or by snakes that eat animals larger than their own heads and toads that save themselves from the jaws of death by puffing up their bodies even larger than the snake can handle (like the snake and toad battling it out on the right), or by the elaborate displays of male birds in their attempts to woo females (like the golden pheasant below), or by kangaroo moms that guard their toddler-like young in their own bodies (like the one on the right). But at closer inspection, we realize that all of these animals are facing similar challenges: All animals are driven to eat and not be eaten, to stay healthy, to make babies, and to keep their babies alive. And animals have developed behavioral tools to achieve these goals, such as ways of finding or making food and a place to live, ways to defend these things, techniques for attracting the opposite sex, and parental methods. The details are extremely diverse across animal groups, but the ultimate goals and many of the strategies are common. And amazingly, the brain systems that regulate these behaviors are common too.In a new synthesis of decades of research spanning the field of behavioral neuroscience, researchers Lauren O’Connell and Hans Hofmann from the University of Texas at Austin show that despite our impressive diversity, mammals, birds, reptiles, amphibians and fish are all molded from the same metaphorical clay. They specifically focus on two brain systems, often called the social behavior network and the mesolimbic reward system.The social behavior network is a term first described in mammals by neuroscientist Sarah Newman to describe several brain regions that are all sensitive to steroid hormones (such as testosterone and estrogen), connect to each other, and are involved in many types of social behavior (including aggression, sexual behavior and parental behavior). We now know that reptiles, birds and fish also have brain areas that are similar in... Read more »
O'Connell, L., & Hofmann, H. (2011) The Vertebrate mesolimbic reward system and social behavior network: A comparative synthesis. The Journal of Comparative Neurology, 519(18), 3599-3639. DOI: 10.1002/cne.22735
O’Connell, L., & Hofmann, H. (2011) Genes, hormones, and circuits: An integrative approach to study the evolution of social behavior. Frontiers in Neuroendocrinology, 32(3), 320-335. DOI: 10.1016/j.yfrne.2010.12.004
- January 23, 2013
- 02:28 PM
- 184 views
The Real Catfish of Lake Tanganyika
by Miss Behavior in The Scorpion and the Frog
Photo of Manti Te'o by Shotgun Spratling and Neon Tommy at WikimediaPoor Manti Te’o may just be the most gullible schlub on the planet. For those of you that haven’t heard the story, the Notre Dame linebacker and runner-up for the 2012 Heisman Trophy led his team to the BCS National Championship Game, despite (or perhaps inspired by) the tremendous personal losses he has suffered this season. Last September, Te’o learned first of the death of his grandmother, and then within hours learned of the death of his girlfriend, Lennay Kekua. But after months of grieving and playing his heart out, Te’o began to receive phone calls from his “dead” girlfriend, telling him she missed him. Totally freaky, right? Notre Dame hired investigators to look into the undead girlfriend and they discovered that not only is Kekua not dead, she was never alive. The girl never existed. And what of Te’o’s relationship with her? According to Te’o, he never actually met her in person: Their entire long-term relationship took place online and over the phone, so he never realized that her entire persona was a fraud. He was completely and totally catfished.He was what? The top definition of catfish at Urban Dictionary reads:“A catfish is someone who pretends to be someone they're not using Facebook or other social media to create false identities, particularly to pursue deceptive online romances. Did you hear how Dave got totally catfished last month?! The fox he thought he was talking to turned out to be a pervy guy from San Diego!”The term apparently originates with the 2010 documentary, Catfish, about a young man who falls in love with a woman on Facebook… who turns out to be someone else. Ew. But why the term catfish? A story in the movie explains that when cod are shipped from North America to Asia, their inactivity can result in mushy meat. Fishermen discovered that putting catfish in the cod tanks will keep the cod active and preserve meat quality. Like catfish for cod, the guy philosophizes, people that have deceptive identities keep idle people active. (The producers of the documentary now produce an MTV series by the same name about this online phenomenon). But it’s not like real catfish can imitate others… Or do they? Three poisionous Lake Tanganyikan catfish. Figure from Jeremy's 2010 Evolution paper.A 2010 paper by Jeremy Wright at the University of Michigan at Ann Arbor documents the first known case of mimicry in catfish. There are several types of mimicry in the animal world. In this case, Jeremy was investigating functional Müllerian mimicry, a phenomenon in which two or more poisonous species mimic each other's predator-deterring warning signals (as opposed to Batesian mimicry, where a non-poisonous animal looks like a poisonous one). It may seem excessive to have both poison and warning coloration, but poison only helps after you’ve been bit. If your predators are smart enough to learn from experience, you can benefit from having more poisonous buddies around that look just like you so that if a predator bites just one of you it will then learn to avoid all of you. Sometimes it pays to look just like everyone else.But just because you look like everyone else doesn’t mean that it is because you’re imitating others. I mean, maybe that’s just the way you look. So how do you know if a bunch of animals that look like one another are using functional Müllerian mimicry?Jeremy studied a number of similarly-colored, poisonous and closely-related catfish species in the African Great Lake, Lake Tanganyika. All of these Tanganyikan catfish species (from the Synodontis genus) have dark spots on a yellowish background and dark fins with white borders. Could this be because of functional Müllerian mimicry?Jeremy put a bunch of largemouth bass each into their own tank. Largemouth bass are predators that use their vision to find and eat most any fish that will fit in their mouths. But these bass were from Michigan, so they’d never had any experience with a poisionous, spotted Synodontis catfish. A clear barrier divided each tank in half and the bass was placed on one side of the divider, and a bite-sized fish was put on the other. The bite-sized fish was either a spotted and poisonous Synodontis multipunctata catfish, a spotted and poisonous Synodontis petricola catfish, or a not-spotted and not-poisonous minnow. He then counted how many times the bass struck the plastic divider in 5 minutes as a measure of how much that bass wanted to eat the bite-sized fish. After the 5 minutes were up, Jeremy removed the divider and watched to see if the bass ate the bite-sized fish. For each bass, he did this every day for 5 days, giving each bass the same species of bite-sized fish every day, so it could learn from its past experiences. A naïve largemouth bass excited to eat a bitesized, but poisonous Synodontis petricola catfish.... Read more »
Wright, J. (2011) CONSERVATIVE COEVOLUTION OF MÜLLERIAN MIMICRY IN A GROUP OF RIFT LAKE CATFISH. Evolution, 65(2), 395-407. DOI: 10.1111/j.1558-5646.2010.01149.x
- January 2, 2013
- 11:18 AM
- 291 views
When The Going Gets Tough, The Tough Become Babies
by Miss Behavior in The Scorpion and the Frog
We celebrate the New Year as a time of rebirth, renewal, and do-overs. We join gyms, swear off our bad habits, and promise to be better people. This is especially true for those of us that have had a rough 2012… Our 2013-version-of-us has got to be better, right? But what if you could get a real do-over? What if you could be a kid again, grow up again, and become a brand new person? As far-fetched as it may sound, some animals do exactly that.Cnidarians (the “C” is silent) are a huge group of aquatic animals that includes jellyfish, corals, and anemones (like the one Nemo lived in – Yeah, that tentacled home was a living animal). They are named after prickly plants known as nettles, or cnides in Greek, and if you touch one you will quickly know why. Cnidarians, armed with stinging cells called nematocysts, sting at the slightest touch.Jellyfish make up many of the cnidarian species, and they have been found in every ocean and at every depth. Some even live in freshwater. The “typical” jellyfish life cycle starts when eggs and sperm are released into the water and find one another. When they do, they form larvae, which you can think of as baby jellyfish. The larvae sink and settle on a hard surface, where they mature into polyps. These polyps are jellyfish in a juvenile stage. The polyps elongate and begin to bud off adult medusa, which are the bell-shaped blobs with tentacles that most of us think of when we think of a jellyfish. Medusa mature to become reproductive adult jellyfish.The jellyfish life cycle by Zina Deretsky at the National Science Foundation (NSF). Image available at Wikimedia.Larval and polyp jellyfish are much more resistant to harsh conditions then are medusa jellyfish. When life gets hard for a jellyfish, perhaps because of starvation, physical damage, temperature changes or salinity changes, those that are in the larval or polyp stages can often shrink and rest in a hibernation-like state while they wait for more favorable conditions. But in some species, young adult medusa can even regress back to the juvenile polyp stage. By reverting back to a juvenile stage, they have more protection from the challenging world around them. In most cases, this reversal to a juvenile state can only happen in young medusa that have not yet developed their gonads. Thus, the onset of sexual reproduction (puberty, if you will) might be regarded as the point of no return in development. However, one species, called the immortal jellyfish, has shown that this rule can be broken. As an adult medusa, the immortal jellyfish is a pea-sized jellyfish with a round bell, bright red stomach and anywhere from 8 to 90 tentacles. It is currently the only known animal that can regress from a fully reproductively mature adult into a juvenile polyp. If exposed to dangerous conditions, immortal jellyfish medusae completely reduce all of their medusa-specific organs and tissues and develop new polyp-specific tissues, essentially becoming kids again!This figure from the Piraino et al. 2004 paper at the Canadian Journal of Zoology shows the life stages of the immortal jellyfish. The adult medusa is in panel (a). Panels (b) and (c) show the medusa tranforming to a ball-like blob as it reverts to a juvenile stage. The green stain in these panels shows the cells initiating this transformation. Panel (d) shows the remnant of a medussa, and the black arrow shows the stalk that is common in the polyp stage. Panel (e) shows the resulting juvenile polyp.But wait! It gets better! Theoretically, if an animal can revert to a juvenile stage at any point in its adult life, it could attain immortality. But if that were true, they would have the classic immortality problem: These animals would reach such high populations they would saturate the world’s oceans…And this may actually be happening.Immortal jellyfish are thought to originally be from the Caribbean, but they have since been discovered worldwide and their populations seem to be growing. Likely, they are hitching rides in the ballast water that is sucked into cargo ships to provide stability. If this is true, the immortal jellyfish polyps could be attaching to the ships’ hulls and settling in for a long voyage to a new home.We don’t yet know if the immortal jellyfish are actually immortal, but it is fun to consider that they might be (although they can still be killed by predators or viruses, so they’re not invincible). And we can take inspiration from them: When the going gets tough, try reverting to your more resilient juvenile self, but be thankful you don’t have to go through middle school again! Happy New Year!Want to know more? Check these out:1. Piraino, S., De Vito, D., Schmich, J., Bouillon, J., & Boero, F. (2004). Reverse development in Cnidaria Canadian Journal of Zoology, 82 (11), 1748-1754 DOI: 10.1139/z04-1742. Miglietta, M., & Lessios, H. (2008). A silent invasion Biological Invasions, 11 (4), 825-834 DOI: 10.1007/s10530-008-9296-0... Read more »
Piraino, S., De Vito, D., Schmich, J., Bouillon, J., & Boero, F. (2004) Reverse development in Cnidaria. Canadian Journal of Zoology, 82(11), 1748-1754. DOI: 10.1139/z04-174
Miglietta, M., & Lessios, H. (2008) A silent invasion. Biological Invasions, 11(4), 825-834. DOI: 10.1007/s10530-008-9296-0
- December 19, 2012
- 10:23 AM
- 237 views
Not Fair! Even Dogs Know the Importance of Gift-Equity
by Miss Behavior in The Scorpion and the Frog
Don't leave out your best friend whengift-giving this holiday season! Photo by Ohsaywhat at Wikimedia.When I was a child, I think one of the things that stressed my mom out most about the holidays was making sure that all of us kids got Christmas gifts worth the exact same amount. Why all the fuss? Because if the value of the gifts wasn’t equal, we were guaranteed to spend our holidays in a chorus of “Not fair!” cries rather than appreciating the holiday bounty and cheer around us. As a species, we have a pretty developed sense of fairness. This sense of fairness is central to our ability to cooperate to achieve goals that are too difficult for one person to accomplish alone. But we’re not the only social species that cooperates… and it turns out, we’re not the only ones with a sense of fairness, either.Domestic dogs and their wild relatives, like wolves and African wild dogs, are very social and have cooperative hunting, territory defense, and parental care. Friederike Range, Lisa Horn, Zsófia Viranyi, and Ludwig Huber from the University of Vienna, Konrad Lorenz Institute, and Wolf Science Center, all in Austria, sought out to test whether domesticated dogs have a sense of fairness.The researchers tested pairs of dogs who had lived together in the same household for at least a year. All of these dogs had been previously trained to give their paw on command, as if giving a handshake. Each pair of dogs was asked to sit in front of an experimenter (one dog was designated the “subject” and the other was the “partner”). In this position, the willingness of the subject dog to shake paws with the experimenter was tested under six different situations.An experimenter asks two dog-buddies to each give her a paw and they wait to see who gets rewarded. Photo from Range et al., PNAS, 2009.In the basic situation, both dogs were asked to give a paw, and both dogs were rewarded with a “low-value” reward (a piece of bread). This happened repeatedly and the researchers measured how many times the subject dogs would give their paw.In another situation, both dogs were asked to give a paw, but the subject dog was rewarded with a “low-value” reward (a piece of bread) while its buddy was rewarded with a “high-value” reward (a piece of sausage). In a third situation, both dogs were asked to give a paw, but only the partner dog was rewarded with a piece of bread (the subject dog got nothing).In the fourth situation, only the subject dog was asked to give a paw, but both dogs were rewarded with a piece of bread.In the fifth situation, the experimenter measured how many times the subject dog would give its paw for a piece of bread if his doggy-buddy wasn’t around.In the last situation, the experimenter measured how many times the subject dog would give its paw for no reward if his doggy-buddy wasn’t around.When both dogs received bread, they were happy to keep giving the experimenter their paw for as long as they were asked to. But when dogs saw their buddy get a piece of bread when they got nothing, they soon refused to give their paw to the experimenter (and started showing signs of stress). You may think this is just what happens when you stop rewarding a dog for doing what you ask, but something different was going on here. The dogs that never got a reward gave their paw to the experimenter for longer when their buddy wasn’t around than if their buddy was around and getting bread treats. Clearly, even dogs know that equal work for unequal pay is not fair.But the doggy-sense-of-fairness is limited. As long as they got their bread when they gave their paw, they really didn’t seem to care (or notice) if their buddy got bread or sausage, or even whether their buddy had to perform the same trick or not.So this holiday season, don’t forget to get a present for your four-legged friend so he doesn’t feel left out. But don’t worry about getting something expensive – He doesn’t care anyway. For him, it’s the gesture that counts. Want to know more? Check these out:1. Range F, Horn L, Viranyi Z, & Huber L (2009). The absence of reward induces inequity aversion in dogs. Proceedings of the National Academy of Sciences of the United States of America, 106 (1), 340-5 PMID: 190649232. Range, F., Leitner, K., & Virányi, Z. (2012). The Influence of the Relationship and Motivation on Inequity Aversion in Dogs Social Justice Research, 25 (2), 170-194 DOI: 10.1007/s11211-012-0155-x ... Read more »
Range F, Horn L, Viranyi Z, & Huber L. (2009) The absence of reward induces inequity aversion in dogs. Proceedings of the National Academy of Sciences of the United States of America, 106(1), 340-5. PMID: 19064923
Range, F., Leitner, K., & Virányi, Z. (2012) The Influence of the Relationship and Motivation on Inequity Aversion in Dogs. Social Justice Research, 25(2), 170-194. DOI: 10.1007/s11211-012-0155-x
- November 28, 2012
- 10:19 AM
- 222 views
Mr. Nanny Makes Mr. Right
by Miss Behavior in The Scorpion and the Frog
Quick! Introduce yourself to this guy before his baby-high wears off! Photo by David Castillo Dominici at FreeDigitalPhotos.net. What happens if you take a wrestler or action star and force him to babysit obnoxious but lovable kids? Well, if you’ve seen movies like The Pacifier with Vin Diesel, The Tooth Fairy with Dwayne ‘The Rock’ Johnson, Kindergarten Cop with Arnold Schwarzenegger, or The Spy Next Door with Jackie Chan, you know that he will fall madly in love both with his young charges and with the closest available woman. Hollywood is so sure of this phenomenon that they have based a whole genre of family movies on it. Now, scientists are finding that Hollywood may be on to something. Prairie voles are one of the only 3-5% of mammals that are monogamous and in which both parents help take care of young. In females, maternal care is regulated in part by the hormones associated with pregnancy, birth and lactation. The fact that males don’t do those things and they still provide paternal care is curious. The fact that male prairie voles will often provide care to offspring that aren’t even their own is even more curious. Will Kenkel, Jim Paredes, Jason Yee, Hossein Pournajafi-Nazarloo, Karen Bales, and Sue Carter at the University of Illinois at Chicago recently explored what happens to male prairie voles when they are exposed to unfamiliar vole pups. Male voles without any experience with females or pups were placed in a new clean cage. Then the researchers put either a pup (that was not related to the male), a dowel rod (an unfamiliar object), or nothing into the cage with them for 10 minutes. Afterwards, they measured oxytocin (a hormone associated with bonding between mothers and their offspring) and corticosterone (a stress hormone) in the males’ blood at different time points. In another study, they also looked at the activity of brain neurons associated with the production of these hormones. A male prairie vole is startled to find a baby in his cage... But then he takes care of it. Video by Will Kenkel. Both adult and juvenile males exposed to a pup for 10 minutes had higher oxytocin and lower corticosterone compared to the males not exposed to a pup. But this effect was short-lived, as male hormone levels quickly evened out again. Most of these males that were exposed to a pup showed alloparental care (care of a baby that is not their own), like approaching the pup, cuddling with it and grooming it. Males with higher oxytocin and lower corticosterone levels were more attentive towards the pups. Additionally, alloparental males exposed to pups had more activity of oxytocin-producing neurons and less activity of neurons associated with corticosterone-production in a specific brain region called the paraventricular nucleus (or PVN for short). Oxytocin is strongly associated with pair bonding in prairie voles, particularly in females, and corticosterone affects pair bonding too (generally increasing pair bonding in males and preventing it in females). If exposure to a pup affects these hormones, maybe it affects how the male would interact with adult females. To test this, the researchers put male voles in a new clean cage and put a pup, a dowel rod, or nothing into the cage with them for 20 minutes. Then they put the males with an unfamiliar adult female for 30 minutes. After getting acquainted with the female, the males were put in a “partner preference apparatus”, which has three connected chambers: a neutral center chamber, a connected chamber with the familiar female tethered into it, and a connected chamber with an unfamiliar female tethered into it. The researchers measured how much time the males spent in each of the three chambers and with each of the two females over the next 3 hours. A prairie vole pair snuggles. Photo from Young, Gobrogge, Liu and Wang paper in Frontiers in Neuroendocrinology (2011) Males that were exposed to a dowel rod or to nothing before they were introduced to a female spent equal amounts of time with each of the two females. But males that were exposed to a pup before they were introduced to a female spent nearly 4 times as much time with that female than with the unfamiliar one. In other words, hanging out with a random pup acted like Love Potion #9 on these bachelor males and made them fall for the next female they encountered! Interestingly, this effect was true not only for the males that acted in an alloparental way towards the pups, but it was also true of males that attacked the pups (The researchers quickly rescued the pups if this occurred). Perhaps, males that were alloparental with the pups had increased oxytocin and males that were aggressive with the pups had increased corticosterone, either of which would make it more likely for them to form a preference for the female they were with. Hmm… Got your eye on a special someone? Try volunteering him to babysit before your next date. Want to know more? Check this out:... Read more »
Kenkel, W., Paredes, J., Yee, J., Pournajafi-Nazarloo, H., Bales, K., & Carter, C. (2012) Neuroendocrine and Behavioural Responses to Exposure to an Infant in Male Prairie Voles. Journal of Neuroendocrinology, 24(6), 874-886. DOI: 10.1111/j.1365-2826.2012.02301.x
- November 21, 2012
- 01:10 PM
- 303 views
Competitive Females
by Miss Behavior in The Scorpion and the Frog
Paula Broadwell, the aggressive competitor. Photo from her Facebook page. By now, you’ve probably heard all about Paula Broadwell, the woman that seduced the notoriously disciplined CIA director, four-star US Army general, husband and father, General David Petraeus. What kind of a woman might be able to sway a man that has such admirable self-control? Broadwell was Petraeus’ biographer, a West Point graduate with a Harvard graduate degree, an Army Reservist thrice recalled to active duty, a fitness champion, Ironman triathlete and even a machine gun model. Her accomplishments are clearly impressive, but maybe the key comes down to her competitive nature. I mean, she did send several threatening e-mails to an attractive socialite and Petraeus family friend, warning her to stay away from her (other) man.When we think about competing for mates, we generally think about males competing for females and breeding territories with horns to duke it out, or elaborate feathers to show off, or dance-offs to demonstrate their physical abilities. But females often have to compete for the high-quality males and breeding territories too. And many of the concepts that apply to males competing for females have been found to also apply to females competing for males.A dark-eyed junco thinking "What you lookin' at?". Photo by Kristal Cain.As much as we know about males competing with one another, we know surprisingly little about females competing with one another, although they clearly do. Kristal Cain and Ellen Ketterson at Indiana University sought out to shed light on female competition and its effect on breeding success. They did this with female Carolina dark-eyed juncos, a socially monogamous songbird species in which both parents care for the young. They were curious whether more aggressive females would also have other competitive traits, like large body size. They also wondered whether aggressive females would have better breeding success.The researchers caught female juncos to measure and put identifying leg bands on them. They then released them and spent their nesting season looking for their nests. When they found a nest, they identified whose nest it was by the female’s leg bands. The researchers tested how aggressive females were towards competing females by placing a caged female within 3 meters of a subject’s nest and watching to see if she swooped at the caged female. Then they kept an eye on the nest to see if the chicks all survived until they fledged (left the nest on their own) or if the nest was destroyed (usually by a predator) before the chicks fledged.A female junco in full-on attack mode. Photo by Kristal Cain.Females that were more aggressive towards “competing” females tended to be bigger and had chicks that were more likely to fledge. Now, if this were a story about competitive males, we might think big aggressive males with more successful chicks might have higher testosterone. Alternatively, low testosterone is often found in males that are better fathers. But these are females… Does it even make sense to talk about testosterone in females? Of course it does! Turns out, males don’t have a monopoly on testosterone; females have it too.The researchers drew blood from the females and then gave them a “testosterone challenge” by injecting them with a hormone called gonadotropin-releasing hormone (or GnRH for short). GnRH is a trigger that causes a series of biological events that result in the gonads producing more hormones, including testosterone. The researchers then drew a second blood sample to measure how much testosterone levels changed in response to the GnRH injection.More aggressive females produced more testosterone in response to the GnRH injection than did less aggressive females. This same effect has also been shown to be true of males behaving aggressively towards each other. I guess males and females really aren’t all that different, eh? But interestingly, females that produced more testosterone in response to the GnRH challenge also had more successful nests.It’s important to keep in mind that these results are correlational. Maybe testosterone makes females bigger and more aggressive and better mothers. Or perhaps having a temper increases your testosterone production. Or maybe some other hormone that increases in response to GnRH (there are many) is responsible for the effects. In any case, females that are bigger and more aggressive and have more successful offspring also produce more testosterone in response to a GnRH injection. Paula Broadwell shows off her aggressive abilities in this KRISS ARMS video (gif'd by Michael Pakradooni).As far as we know, no one has given Paula Broadwell a testosterone challenge, but she undoubtedly has a number of correlated competitive traits. Paula Broadwell is a competitive, physically fit, attractive parent who has shown that she can out-compete the spouses of high-quality mates… But then again, so is David Petraeus.Want to know more? Check this out:Cain, K., & Ketterson, E. (2011). Competitive females are successful females; phenotype, mechanism, and selection in a common songbird Behavioral Ecology and Sociobiology, 66 (2), 241-252 DOI: 10.1007/s00265-011-1272-5 ... Read more »
Cain, K., & Ketterson, E. (2011) Competitive females are successful females; phenotype, mechanism, and selection in a common songbird. Behavioral Ecology and Sociobiology, 66(2), 241-252. DOI: 10.1007/s00265-011-1272-5
- November 7, 2012
- 10:10 AM
- 357 views
Political Animals
by Miss Behavior in The Scorpion and the Frog
Now that we are finally on the other side of one of the longest, most expensive political campaign seasons of United States history, we find ourselves with a new mixed-bag of leaders. Our nation’s decision-makers include career politicians and new freshman politicians; they include lawyers, military members, doctors, businessmen, farmers, ministers, educators, scientists, pilots, and entertainers; they include Protestants, Catholics, Jews, Quakers, Mormons, Buddhists and Muslims; they include white Americans, African Americans, Asian Americans, and Hispanic and Latino Americans; they include men and women; they include straight and gay people; and oh yeah, they include Republicans and Democrats. With so many differences that generate so many viewpoints, how will they ever find common ground to make the kind of decisions that will move our nation in a positive direction? Hey, Look guys! We make a peace sign! Image from Wikimedia. Research into group decision-making in social animals has shown that ants, fish, birds, and bees have all discovered strategies to make intelligent group decisions. If they can do it, we can do it, right? What can we learn from these critters about harnessing the knowledge in all of us to move our whole group in the best possible direction? We will explore these insights in this post, which is a mash-up of two previous posts. To see the originals, check out Can a Horde of Idiots Be a Genius? and Why This Horde of Idiots Is No Genius.Jean-Louis Deneubourg, a professor at the Free University of Brussels, and his colleagues tested the abilities of Argentine ants (a common dark-brown ant species) to collectively solve foraging problems. In one of these studies, the ants were provided with a bridge that connected the nest to a food source. This bridge split and fused in two places (like eyeglass frames), but at each split one branch was shorter than the other, resulting in a single shortest-path and multiple longer paths. After a few minutes, explorers crossed the bridge (by a meandering path) and discovered the food. This recruited foragers, each of which chose randomly between the short and the long branch at each split. Then suddenly, the foragers all started to prefer the shortest route. How did they do that?This figure from the Goss et al 1989 paper in Naturwissemschaften shows (a) the design of a single module, (b) ants scattered on the bridge after 4 minutes (I promise they’re there), and (c) ants mostly on the shortest path after 8 minutesYou can think of it this way: a single individual often tries to make decisions based on the uncertain information available to it. But if you have a group of individuals, they will likely each have information that differs somewhat from the information of others in the group. If they each make a decision based on their own information alone, they will likely result in a number of poor decisions and a few good ones. But if they can each base their decisions on the accumulation of all of the information of the group, they stand a much better chance of making a good decision. The more information accumulated, the more likely they are to make the best possible decision.In the case of the Argentine ant, the accumulated information takes the form of pheromone trails. Argentine ants lay pheromone trails both when leaving the nest and when returning to the nest. Ants that are lucky enough to take a shorter foraging route return to the nest sooner, increasing the pheromone concentration of the route each way. In this way, shorter routes develop more concentrated pheromone trails faster, which attract more ants, which further increase pheromone concentration of the shortest routes. In this way, an ant colony can make an intelligent decision (take the shortest foraging route) without any individual doing anything more intelligent than following a simple rule (follow the strongest pheromone signal).Home is where the heart is. Photo of a bee swarm by Tom SeeleyHoneybee colonies also solve complicated tasks with the use of communication. Tom Seeley at Cornell University and his colleagues have investigated the honeybee group decision-making process of finding a new home. When a colony outgrows their hive, hundreds of scouts will go in search of a suitable new home, preferably one that is high off the ground with a south-facing entrance and room to grow. During this time, the house-hunters will coalesce on a nearby branch while they search out and decide among new home options. This process can take anywhere from hours to days during which the colony is vulnerable and exposed. But they can’t be too hasty: choosing a new home that is too small or too exposed could be equally deadly. Although each swarm has a queen, she plays no role in making this life-or-death decision. Rather, this decision is made by a consensus among 300-500 scout bees that results after an intense “dance-debate”. If a scout finds a good candidate home, she returns to the colony and performs a waggle dance, a dance in which her body position and movements encode the directions to her site and her dancing vigor relates to how awesome she thinks the site is. Some scouts that see her dance may be persuaded to follow her directions and check out the site for themselves, and if impressed, may return to the hive and perform waggle dances too. Or they may follow another scout’s directions to a different site or even strike out on their own. Over time, scouts that are less enthusiastic about their discovered site stop dancing, in part discouraged by dancers for other sites that bump heads with them and beep at them in disagreement. Eventually, the majority of the dancing scouts are all dancing the same vigorous dance. But interestingly, few scouts ever visit more than one site. Better sites simply receive more vigorous “dance-votes” and then attract more scouts to do the same. Like ants in search of a foraging path, the intensity of the collective signal drives the group towards the best decision. Once a quorum is reached, the honeybees leave their branch as a single united swarm and move into their new home, which is almost always the best site. ... Read more »
Couzin, I. (2009) Collective cognition in animal groups. Trends in Cognitive Sciences, 13(1), 36-43. DOI: 10.1016/j.tics.2008.10.002
List, C., Elsholtz, C., & Seeley, T. (2009) Independence and interdependence in collective decision making: an agent-based model of nest-site choice by honeybee swarms. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1518), 755-762. DOI: 10.1098/rstb.2008.0277
Seeley, T., Visscher, P., Schlegel, T., Hogan, P., Franks, N., & Marshall, J. (2011) Stop Signals Provide Cross Inhibition in Collective Decision-Making by Honeybee Swarms. Science, 335(6064), 108-111. DOI: 10.1126/science.1210361
Dell'Ariccia, G., Dell'Omo, G., Wolfer, D., & Lipp, H. (2008) Flock flying improves pigeons' homing: GPS track analysis of individual flyers versus small groups. Animal Behaviour, 76(4), 1165-1172. DOI: 10.1016/j.anbehav.2008.05.022
- October 31, 2012
- 11:48 AM
- 296 views
True Blood: Vampires Among Us
by Miss Behavior in The Scorpion and the Frog
Who is your favorite vampire? Are you a fan of Edward Cullen, Bill Compton or Stefan Salvatore? Or do you prefer the classic Dracula, elegant Lestat, or butt-kicking Selene?Vampires have fascinated us since the Middle Ages, when a hysteria of vampire sightings spread across Eastern Europe. We now know that many of these “vampires” were actually victims of diseases like tuberculosis or bubonic plague that cause bleeding in the lungs (and elsewhere), resulting in the disturbing effect of blood appearing at the lips. Add this attribute to the already poorly understood physiology of decomposing corpses and the cases in which people mistakenly buried alive got up and left their graves, and voila! Vampire mythology is born. So vampires don’t really exist… Or do they?Actually, there are many animals that feed on blood. So many in fact, that there is a scientific term for blood-eating, hematophagy. And why not? Blood is fluid tissue, chock full of nutritious proteins and lipids and a source of water to boot. And if you don’t kill your prey to feed, the food supply replenishes itself. Here are just some of these animal vampires living among us: Vampire batA vampire bat smiles for the camera from his Peruvian cave. Photo from Wikimedia. Vampire bats are our most famous animal vampires, and the ones that most resemble our vampiric lore. There are three species of vampire bats that live from Mexico down through Argentina. Two of them, the hairy-legged and white-winged vampire bats, feed mostly on birds. The common vampire bat feeds more on mammals, like cows, horses, and the occasional human. Their razor sharp teeth cut a tiny incision in their victims and their anticoagulant saliva keeps the blood flowing. Like Dracula, vampire bats sleep by day and hunt by night. But these vampires are not loners like Dracula: They live in colonies of about 100 animals, and in hard times will share their blood-harvest and care for one another’s young.Vampire finchThe Galapagos Islands are the famous home to numerous finch species, each one with a beak shape specially adapted to their preferred food source. For most of these finches, their food of choice is a type of seed or nut that is appropriately sized for their beak shape and strength. But the vampire finch (also called the sharp-beaked ground finch for obvious reasons) uses its long sharp beak to feed on blood. Their most common victims are their booby neighbors (named for less obvious reasons).CandirúA tiny candirú catfish (being measured in cm) strikes terror into the souls of Amazonian fishermen. Photo by Dr. Peter Henderson at PISCES Conservation LTD. Photo at Wikimedia.The tiny Amazonian candirú catfish is legendary for one documented case (and several undocumented ones) in which a candirú swam up a local man’s urine stream into his penis, where it attached to feed on his blood. Although terrifying, this is not typical candirú behavior. Actually, it was all just a misunderstanding. You see, candirú catfish do feed on blood, but they usually feed from the highly vascularized gills of other Amazonian fish. As we saw last week, the gills of freshwater fish release high quantities of urea, a major component of urine. So to a hungry candirú, your pee smells an awful lot like a fish-gill blood dinner. Just another reason to not pee where you swim.LampreyNotice the sharp-toothed sucker mouth of the river lamprey. Photo by M. Buschmann at Wikimedia.Lampreys are species of jawless fish. With their eel-like bodies and disc-shaped mouths filled with circles of razor-sharp teeth, they look like something from science fiction horror. Although some lamprey species are filter feeders, others latch onto the sides of other fish, boring into their flesh and feeding on their blood. Once attached, they can hitch a ride on their victim for days or even weeks.LeechA European medicinal leech. Photo by H. Krisp at Wikimedia.Leeches are the earthworm’s bloodsucking cousins. With three blade-like mouthparts, they slice into their victims, leaving a Y-shaped incision. They produce anticoagulants to prevent premature clotting of their bloodmeals, which can weigh up to five times as much as the leach itself. The bloodletting and anticoagulant abilities of leeches have led them to be used medicinally in ancient India and Greece as well as in modern medicine.Female mosquitoA female mosquito getting her blood meal. Photo by at Wikimedia.Most of the time, mosquitos use their syringe-like mout... Read more »
SCHLUTER, D., & GRANT, P.R. (1984) ECOLOGICAL CORRELATES OF MORPHOLOGICAL EVOLUTION IN A DARWINS FINCH, GEOSPIZA-DIFFICILIS. EVOLUTION, 38(4), 856-869. info:/
Francischetti, I. (2010) Platelet aggregation inhibitors from hematophagous animals. Toxicon, 56(7), 1130-1144. DOI: 10.1016/j.toxicon.2009.12.003
- October 24, 2012
- 11:32 AM
- 397 views
The Smell of Fear
by Miss Behavior in The Scorpion and the Frog
Several animals, many of them insects, crustaceans and fish, can smell when their fellow peers are scared. A kind of superpower for superwimps, this is an especially useful ability for prey species. An animal that can smell that its neighbor is scared is more likely to be able to avoid predators it hasn’t detected yet. Who can smell when you're scared? Photo provided by Freedigitalphotos.net.“What does fear smell like?” you ask. Pee, of course. I mean, that has to be the answer, right? It only makes sense that the smell of someone who has had the piss scared out of them is, well… piss. But do animals use that as a cue that a predator may be lurking?Canadian researchers Grant Brown, Christopher Jackson, Patrick Malka, Élisa Jaques, and Marc-Andre Couturier at Concordia University set out to test whether prey fish species use urea, a component of fish pee, as a warning signal.A convict cichlid in wide-eyed terror... Okay, fine. They're always wide-eyed. Photo by Dean Pemberton at Wikimedia.First, the researchers tested the responses of convict cichlids and rainbow trout, two freshwater prey fish species, to water from tanks of fish that had been spooked by a fake predator model and to water from tanks of fish that were calm and relaxed. They found that when these fish were exposed to water from spooked fish, they behaved as if they were spooked too (they stopped feeding and moving). But when they were exposed to water from relaxed fish, they fed and moved around normally. Something in the water that the spooked fish were in was making the new fish act scared!To find out if the fish may be responding to urea, they put one of three different concentrations of urea or just plain water into the tanks of cichlids and trout. The cichlids responded to all three doses of urea, but not the plain water, with a fear response (they stopped feeding and moving again). The trout acted fearfully when the two highest doses of urea, but not the lowest urea dose or plain water, were put in their tank. Urea seems to send a smelly signal to these prey fish to “Sit tight – Something scary this way comes”. And the more urea in the water, the scarier!But wait a minute: Does this mean that every time a fish takes a wiz, all his buddies run and hide? That would be ridiculous. Not only do freshwater fish pee a LOT, many are also regularly releasing urea through their gills (I know, gross, right? But not nearly as gross as the fact that many cigarette companies add urea to cigarettes to add flavor).The researchers figured that background levels of urea in the water are inevitable and should reduce fishes fear responses to urea. They put cichlids and trout in tanks with water that either had a low level of urea, a high level of urea, or no urea at all. Then they waited 30 minutes, which was enough time for the fish to calm down, move around and eat normally. Then they added an additional pulse of water, a medium dose of urea, or a high dose of urea. Generally, the more urea the fish were exposed to for the 30 minute period, the less responsive they were to the pulse of urea. Just like the scientists predicted.A rainbow trout smells its surroundings. Photo at Wikimedia taken by Ken Hammond at the USDA.But we still don’t know exactly what this means. Maybe the initial dose of urea makes the fish hide at first, but later realize that there was no predator and decide to eat. Then the second pulse of urea may be seen by the fish as “crying wolf”. Alternatively, maybe the presence of urea already in the water masks the fishes’ ability to detect the second urea pulse. Or maybe both explanations are true.Urea, which is only a small component of freshwater fish urine, is not the whole story. Urea and possibly stress hormones make up what scientists refer to as disturbance cues. Steroid hormones that are involved in stress and sexual behaviors play a role in sending smelly signals in a number of species, so it makes sense that stress hormones may be part of this fearful fish smell. But fish also rely on damage-released alarm cues and the odor of their predators to know that a predator may be near. Scientists are just starting to get a whiff of what makes up the smell of fear.Want to know more? Check these out:1. Brown, G.E., Jackson, C.D., Malka, P.H., Jacques, É., & Couturier, M-A. (2012). Disturbance cues in freshwater prey fishes: Does urea function as an ‘early warning cue’ in juvenile convict cichlids and rainbow trout? Current Zoology, 58 (2), 250-2592. Chivers, D.P., Brown, G.E. & Ferrari, M.C.O. (2012). Evolution of fish alarm substances. In: Chemical Ecology in Aquatic Systems. C. Brömark and L.-A. Hansson (eds). pp 127-139. Oxford University Press, Oxford.3. Brown, G.E., Ferrari, M.C.O. & Chivers, D.P. (2011). Learning about danger: chemical alarm cues and threat-sensitive assessment of predation risk by fishes. In: Fish Cognition and Behaviour, 2nd ed. C. Brown, K.N. Laland and J. Krause (eds). pp. 59-80, Blackwell, London. 3. ... Read more »
Brown, G.E., Jackson, C.D., Malka, P.H., Jacques, É., & Couturier, M-A.,. (2012) Disturbance cues in freshwater prey fishes: Does urea function as an ‘early warning cue’ in juvenile convict cichlids and rainbow trout?. Current Zoology, 58(2), 250-259. info:/
- October 10, 2012
- 11:54 AM
- 384 views
Mind-Manipulating Slave-Making Ants!
by Miss Behavior in The Scorpion and the Frog
An entire colony enslaved by an alien species to care for their young. Slave rebellions quelled by mind manipulation. It sounds like science fiction, right? But it really happens!Myrmoxenus ravouxi (called M. ravouxi for “short”) is a slave-making ant species in which the queen probably wears a chemical mask, matching the scent of a host species in order to invade their nest without detection. Once inside, she lays her eggs for the host species workers to care for. Armies of M. ravouxi workers then raid these host colonies to steel their brood to become future slave-laborers to serve the needs of the M. ravouxi colony.A M. ravouxi queen throttling a host queen. Photo by Olivier Delattre.Enslaved worker ants could rebel: They could destroy the parasite brood or at least not do a good job caring for them. But to selectively harm the parasite brood without harming their own nests’ brood, the host ants would have to be able to tell them apart. Ants learn the smell of their colony in their youth, so any ants born to an already-parasitized colony would likely not be able to tell apart parasite ants from their own species. But what about ants that were born to colonies before they were invaded?Olivier Delattre, Nicolas Châline, Stéphane Chameron, Emmanuel Lecoutey, and Pierre Jaisson from the Laboratory of Experimental Ethology in France figured that compared to ant species that were never hosts to M. ravouxi colonies, ant species that were commonly hosts of M. ravouxi colonies would be better able to discriminate their own species’ brood from M. ravouxi brood. Host species may even be better at discriminating in general.The researchers collected ant colonies from near Fontainebleau and Montpellier in France. They collected M. ravouxi colonies and colonies of a species that they commonly parasitize (but were not parasitized at the time): Temnothorax unifasciatus (called T. unifasciatus for “short”). The researchers also collected T. unifasciatus that were parasitized by M. ravouxi at the time. Additionally, they collected colonies of T. nylanderi and T. parvulus, two species that are never parasitized by M. ravouxi. (Sorry guys. All these species go by their scientific names. But really, that just makes them sound all the more mysterious, right?). The researchers took all their ant colonies back to the lab and housed them in specialized plastic boxes (i.e. scientific ant-farms).On the day of the tests, the scientists removed a single pupa (kind of like an ant-toddler) from one nest and placed it into a different nest of the same species or back in its own nest. They did this for colonies of both non-host species and for colonies of host species T. unifasciatus that were not parasitized at the time. Then they counted how many times the workers bit the pupa (an aggressive behavior) or groomed the pupa (a caring behavior).Workers from all three species bit the pupa that was not from their colony more than they bit their own colony’s pupa. But the T. unifasciatus (the host species) were even more aggressive to foreign pupa than the other species. And only the T. unifasciatus withheld grooming from the pupa that was not from their colony compared to the one that was from their colony. Although all three species seemed to be able to tell the difference between a pupa from their own nest versus one from another nest, only the species that is regularly enslaved by M. ravouxi decreased care to foreign young. So that is what these ants do when they are not enslaved. How do you think enslaved ants respond to their own species’ young compared to M. ravouxi young? A 1975 cover of Galaxie/Bis, a French science fiction magazine, by Philippe Legendre-Kvater. Image from Wikimedia.The researchers repeated the study using enslaved T. unifasciatus, placing either a pupa of their own species from a different nest or a M. ravouxi pupa in with their brood. Even though prior to M. ravouxi takeover the T. unifasciatus bit foreign pupa more than their own, after M. ravouxi takeover they didn’t bite foreign pupa of their own species or M. ravouxi pupa very much. Not only that, but they groomed the M. ravouxi pupa more than the pupa of their own species! Ah hah! Mind control!This, my friends, is the kind of truth that science fiction is made from.But how might this work? Ants born to an enslaved colony would be exposed to both their own odors and the M. ravouxi odors. Because ants learn the smell of their colony in the first few days after they emerge from their eggs, these enslaved ants would have a broader set of smells that they may perceive as being “within the family”. That would explain why the enslaved T. unifasciatus ants didn’t attack either the foreign-born T. unifasciatus or the M. ravouxi young, but it doesn’t explain why the enslaved ants provided more care to the M. ravouxi than they did to their own species. One possibility is that the M. ravouxi produce more or especially attractive odors to encourage the host workers to take care of them.There is still more to learn about this system: How exactly may the M. ravouxi be hijacking the pheromonal systems of their host species? How are the host species protecting themselves from exploitation? I guess we’ll have to wait for the sequel.Want to know more? Check this out:Delattre, O., Chȃline, N., Chameron, S., Lecoutey, E., & Jaisson, P. (2012). Social parasite pressure affects brood discrimination of host species in Temnothorax ants Animal Behaviour, 84, 445-450 DOI: 10.1016/j.anbehav.2012.05.020 ... Read more »
Delattre, O., Chȃline, N., Chameron, S., Lecoutey, E., & Jaisson, P. (2012) Social parasite pressure affects brood discrimination of host species in Temnothorax ants. Animal Behaviour, 445-450. DOI: 10.1016/j.anbehav.2012.05.020
- October 3, 2012
- 11:44 AM
- 321 views
It Feels Good When You Sing a Song (In Fall)
by Miss Behavior in The Scorpion and the Frog
Most male songbirds will sing when they see a pretty female during the breeding season. But some male songbirds sing even when it’s not the breeding season. Why do so many birds sing in fall at all? Maybe singing feels good… But how do you ask a bird if it feels good to sing? European starlings are one of those bird species that sing both in spring (the breeding season) and in fall (not the breeding season). Lauren Riters, Cindi Kelm-Nelson, and Sharon Stevenson at the University of Wisconsin at Madison did a series of ingenious experiments to ask starlings if and when it feels good to sing.A European starling sings his fall-blues away. Photo by Linda Tanner at Wikimedia.Psychologists have long used a paradigm called conditioned place preference (CPP) to evaluate whether an animal finds something rewarding or pleasurable. CPP is based on the idea that if an animal experiences something meaningless while at the same time experiencing something else that is rewarding, the animal will learn to associate these two things with each other in a phenomenon called conditioning. For example, a puppy that has learned that every time it sits it gets a treat, will find itself sitting more often. A researcher can also compare how rewarding different types of treats are. If we want to know if puppies like carrots or steak better, we can give one group of puppies a carrot every time they sit and another group of puppies a piece of steak every time they sit. If the group of puppies that are conditioned with steak spend more time sitting, we can conclude that steak is more rewarding to puppies than carrots are.Lauren and Sharon used this principle to ask starlings if singing is rewarding. They put spring starlings in a cage with a nestbox and a female and let them sing away, while counting how many songs they sang in 30 minutes. Then they immediately put them in another cage that was decorated with yellow materials on one side and green materials on the other, but they restricted each bird to only one of the two colored sides. This is the conditioning phase in which the bird learns to associate the colored cage with the feeling they get from singing. The next day, they put the starlings in the yellow and green cage without restrictions so they could choose what side they wanted to hang out in. If singing is rewarding, we would expect starlings that sang a lot to spend more time on the side with the color they were placed in the day before. Do people that sing in the car spend more time in the car? Photo by freedigitalphotos.net.That didn’t happen. The spring starlings spent the same amount of time in the yellow or green side of the cage regardless of how much they sang the day before.But when Lauren and Sharon did the same test with fall starlings singing without a female, there has a huge effect: Males that sang more spent much more time on the colored side of the cage they were placed in the day before. Singing, for a male starling, is apparently rewarding in fall, but not in spring. This result actually makes a lot of sense. In spring, males sing to attract and court females, so they are rewarded by the feeling they get from the female’s response, not from the act of singing itself. But in fall, males are not attracting females. So why do they sing in fall? Because it feels good.It looks like Sesame Street got it right with their 1970s song “It Feels Good When You Sing a Song”:You can't go wrongwhen you're singing a songSing it loud, sing it strongIt feels good when you sing a song But why does singing feel good? At least some of the reason, it seems, is opioids. Not quite what Sesame Street had in mind, but hey.Despite their reputation for being one of the world’s oldest drugs, many opioids are naturally occurring neuropeptides (brain chemicals). They are involved in pain relief and euphoria, commonly combined in the phenomenon of runner’s high. Could opioids be involved in the feel-good sensation created by singing? Maybe.Cindi, Sharon and Lauren suspect that singing in fall causes male starlings to release opioids in their little brains, which makes singing more rewarding and makes them want to sing more. But how do we know how much opioid an animal has in its brain? Hmmm… Opioids cause analgesia (pain relief). Therefore, if singing a lot in fall releases more opioids, then birds that sing a lot in fall should be more pain-tolerant, right? The researchers let male starlings sing and counted how many songs they produced for 20 minutes. Then they dipped their foot in uncomfortably warm water and timed how long it took for the bird to pull its toes out. Fall males that sang more took longer to pull their feet out of the birdy foot-spa than did the males that sang less.Interestingly, if you give starlings a drug to enhance opioids, they leave their feet in the foot-spa longer than if you give them a drug to block opioids. So it seems that singing in fall increases pain tolerance in the same way that opioids do, likely because the act of singing in fall causes the brain to release its own opioids. (Although it is also possible that birds that produce more opioids feel like singing more).And what about singing in spring? When Cindi, Sharon and Lauren repeated the study with spring starlings, these birds did not get pain relief from singing. Again, they are probably rewarded by their interactions with females and not the act of singing.So if you ever find yourself in pain, justSingSing a songMake it simpleTo last your whole life longDon't worry that it's not good enoughFor anyone else to hearSingSing a songLa la la la la la la la la la laLa la la la la la laWant to know more? Check these out: 1. ... Read more »
Riters LV, & Stevenson SA. (2012) Reward and vocal production: song-associated place preference in songbirds. Physiology , 106(2), 87-94. PMID: 22285212
Kelm-Nelson, C.A., Stevenson, S.A., & Riters, L.V. (2012) Context-dependent links between song production 1 and opioid-mediated analgesia in male European starlings (Sturnus vulgaris). PLOS One, 7(10). info:/
Riters LV, Schroeder MB, Auger CJ, Eens M, Pinxten R, & Ball GF. (2005) Evidence for opioid involvement in the regulation of song production in male European starlings (Sturnus vulgaris). Behavioral neuroscience, 119(1), 245-55. PMID: 15727529
Kelm CA, Forbes-Lorman RM, Auger CJ, & Riters LV. (2011) Mu-opioid receptor densities are depleted in regions implicated in agonistic and sexual behavior in male European starlings (Sturnus vulgaris) defending nest sites and courting females. Behavioural brain research, 219(1), 15-22. PMID: 21147175
topics
join us!
Do you write about peer-reviewed research in your blog? Use ResearchBlogging.org to make it easy for your readers — and others from around the world — to find your serious posts about academic research.
If you don't have a blog, you can still use our site to learn about fascinating developments in cutting-edge research from around the world.
