PREDATOR Vs. PREY: A SQUIRREL'S "TAIL"

Video of Squirrel Vs. Snake

In the food chain the predators are seen as the most victories when compared to the prey they consume. Most of the predators have more then one advantage over their prey whether its sheer strength or physical size. Due to nature, the bigger animals always pray on the smaller animals, if that were always true you would assume that all the preys would be extent. As most of us know, that is not the case. Almost all Preys have certain behavior or traits that would help them save themselves or their young ones form a predator. For example, the moths that we learned in our first week of Animal Behavior class, uses its auditory receptors witch transmits information to the neurons that control the wings. The auditory receptors help the moth detect high-intensity ultrasounds that is similar to its predator the Bat. Like the moths squirrels also has similar traits that help them escape form their many predators, one of them being their ability to climb trees. Unlike the moth the squirrel would also stand-up and fight some predators even when  they are twice its size like the Snakes. 

For a while we have known that squirrel unlike many other preys would if they have to will fight back to its predators. They use their characteristic traits such as their sharp teeth's to bite, its leg to kick sands, and its sharp claws to scratch sot to fight back. Animal Behaviorist Aaeon Rundus form University of California, Davis has found that the squirrel has a very unique way of using its tail to defend themselves from their most common predator the snakes. It seems that the squirrel are somehow able to change the temperature of its tail depending on the type of snake they are up against. When up against a rattlesnake the squirrel would heat up its tail so to confuse the snake's infrared heat sensors, making the snake assume that it's up against another predator. When up against a gopher snake the tails seems to have cooled because gopher snake has no inferred sensors. to understand this behavior better Rundus designed a robotic squirrel with a heat changing tail. Rundus found that when the tail is warm the rattlesnakes seem to feel threatened and so rather then try to eat the squirrel the snakes become rather defensive. In this way the squirrel has more time to get away or fight. 

Moths and Squirrel are just some of the many type of prey that has over time developed distinctive characteristic to help survive in this ruthless place we call earth.

By: Tenzing Y. Dundutsang

Who Needs Males?!?

http://www.youtube.com/watch?v=KYp_Xi4AtAQ

Ever since I saw Mr. Miyagi take a leaf disguised praying mantis from the tree in one of the karate movies, they've peeked my interest with their still-as-statues eating habits and graceful natures. They have a long thorax that increases their field of vision as well as granting them the ability to turn their heads 180 degrees. They are lean, green, snaring machines! Anything from flies and moths to small frogs and hummingbirds can find themselves on the menu for these strikingly fast killers!

Even though these agile hunters have a diverse diet, cannibalism is far from uncommon. In fact it's a trait that's favored! Male praying mantis' have little to no chance of mating and living to tell the tale. Sorry boy's, no bragging about that night! The mating is done in a series of three steps. First the larger female mantis meets the smaller male mantis. Then the male gets into mating position and he puts his sperm in her, fertilizing her hundreds of eggs, perhaps loosing his head at the same time. Male praying mantis' can afford to loose their heads and use it as a sacrifice because their neural messages to mate aren't located in their heads, so even after they are beheaded they will continue to breed with the larger female. Then, when the male is finished, he will try to run away, whether he's beheaded or not. The female will either try and catch the male, if she didn't already have him, or continue eating him so that he would be the first nurishing meal to the eggs he'd just finished fertilizing.

http://animals.nationalgeographic.com/animals/bugs/praying-mantis.html

http://www.insecta-inspecta.com/mantids/praying/index.html

Posted By: Ada Marie Flores (2)

UPDATE (September 30, 2008)

My updates are at the end of the comment section. I wasn't 100% sure how to correctly post it on this, so I wrote it in my comments like the teacher said I could. Sorry if this inconveniences you.

Human-like Social Skills in Dogs?

The modern day domesticated dog has evolved over time to become man’s best friend. It has the ability to follow learned commands and perform tricks, but just how closely related are a dogs social skills to humans and how did it come about? A study done by Brian Hare and Michael Tomasello attempts to answer these questions. They focused their hypothesis on the idea of convergent evolution and a few simple tests.

To test the dog’s abilities at understanding human-like social communicative behavior a piece of food was hidden beneath one of a few cups. Puppies and adult dogs alike were able to consistently and accurately locate the hidden food by following only the cue of a person pointing at the correct cup. The dogs were also able to locate the food when the person nodded or bowed toward the correct cup as well as if the person walked towards the wrong cup but pointed at the correct one. When chimpanzees were given the same tasks they were unable to follow the cues while human children around 14 months of age and dogs/puppies were able to get these tasks correct on their first try. Another line of research focused on the idea that dogs can also understand what humans can see. In this experiment a person would throw a dog a ball then turn their back to the dog. Upon returning the dogs almost always went around to the front of the person when bringing the ball back. Another test involved a dog’s preference to beg when given the choice of two people from the person whose eyes or head were not covered. It is because children and domesticated dogs were able to perform these tasks while other closely related primate species and wolves were not that researchers believe convergent evolution is involved. Convergent evolution is the idea that unrelated organisms separately evolved similar traits to adapt to their environment.

These canine abilities to read human social-communicative behaviors it would seem have evolved over time. It is concluded within the article that this most likely occurred during the canine domestication process over tens of thousands of years. This has been shown in studies involving domesticated foxes that the selection for behaviors against fear and aggression towards human’s produces foxes that perform as well as the dogs did with the social pointing and gazing cues of humans. While the untamed foxes of the study were unable to perform in the same manner. This behavior selection is believed to be the role that resulted in the evolution of human-like social skills in dogs.

Brian Hare and Michael Tomasello
Science Direct Vol. 9, Issue 9, September 2005 Pgs 439-444
The full article can be viewed here.

Posted by Lindsay Goodyear (2)

Dogs Don’t Share

Have you ever had two or more dogs living together under one household? Well if you have I am sure you’ve experienced their lack of ability to share. The article, Why Dogs Don’t Share, by Daniel Estep and Suzanne Hetts clearly explains how the meaning of sharing is different for dogs and humans. A typical person who owns two or more dogs will try and divide everything between the dogs equally. Well, if they do this they will notice that one dog will always try to take stuff away from the other. This is because dogs don’t live by equality they live by a dominance hierarchy

Dogs rank themselves from high to low. The top dog is most often called the alpha , the second ranking dog the beta, and so on and so forth. They rank themselves to determine who gets what first. They determine rank status by threats and aggression. When all the ranking is sorted out there are no fights or threats, because the submissive dogs just wait their turn and give the more dominate dogs their way. Overall, dogs are meant to live this way and humans need to let them go through their process or else they will never get along.

Posted By: Chantal Gomes (2)

Update

Response to Amy Kawazoe
Yes, this does still occur when dogs in the same house get along. The fact that they have a ranking system has nothing to do with whether or not they get along. This is just a dogs way of life. They develop a ranking system no matter what.

Response to Julie Riley
Giving each dog a certain amount of stuff each day actually doesn't help them at all. All this does is enforce human sharing, equality, on the dogs. This will not teach the dogs anything or prevent them from going about their natural instinct of ranking. Therefore, there is no way they can adopt to lose this behavior, it is a part of their lifestyle.

Response to Amanda Joyce
Dogs base dominance on threats and aggression. Basically, they fight their way up to the top. Whoever can defeat the others gains dominance.

Response to Katie Cole
Cats do have a hierarchy. The hierarchy between cats and dogs is quite different. Dogs have and absolute hierarchy where an individual holds a position until it is beat for its place. Cats on the other hand have a relative hierarchy where individuals switch position depending on the situation. You can read more about it here.

Wasps Remember Past Rivals

It is hard not to remember a person you’ve previously fought with. Paper wasps (Polistes fuscatus) aren’t too bad compared to humans when it comes to remembering prior social interactions with particular individuals. A comb nest, which usually houses hundreds of wasps, is also the stage of intense fights among nest founding queens eager to establish relative dominance ranks. But these wasp queens recognize individuals they’ve fought with previously and save themselves the trouble of fighting again.

Elizabeth Tibbetts and Michael Sheehan of the University of Michigan, Ann Arbor tested whether wasps remember their former rivals. 50 unrelated wasp queens were tested in four different encounters over eight days. Initially, wasps encountered a new social partner and naturally fought against each other. But after 24 hours, the wasps were removed to separate cages, and the same wasps interacted again 7 days later. This time, instead of fighting, they mostly kept to themselves. To make sure that the lack of hostility was not due to waning motivation over time, Tibbetts and Sheehan introduced the wasps to new play dates on the days before and after the reunion, and fighting ensued.

It is surprising that creatures with such tiny brains can have such good social memories. Tibbetts had previously found that paper wasps appear to use facial patterns to distinguish among their nestmates.

Social insects, including the wasps, were once thought to have simple, undifferentiated relationships. Yet the wasps’ robust social memories are an essential component of complex relationships. The fact that even these small-brained invertebrates can form cognition-based social relationships means that perhaps it doesn’t take a big brain to process basic social cognition.

http://www.current-biology.com/content/article/abstract/?uid=PIIS0960982208008993

http://sciencenow.sciencemag.org/cgi/content/full/2008/922/3

Update 09/29/08:

Each colony of paper wasps has a number of queens, who fight each other and end up ranked from top queen to all-around loser queen. So there exists a social hierarchy.

The queens can found nests alone or in groups. The survival of nest that starts off with only one foundress is low that an individual queen has more chance of being reproductively successful by working with a group of queens and fighting for dominance of the resulting nest. The nest then fades into functional haplometrosis as one of the original foundresses becomes dominant. But after the mating season is over, the subordinate queens usually leave to form their own nests. Therefore fighting usually takes place among the queens only.

The researchers only did the experiment in which the wasps were separated for 7 days, and it demonstrated the most robust social memory shown in an insect. No research has been done on how long it will take for the wasp’s memory to fade.

It has been suggested that wasps use variable visual features for individual recognition, and examples of some facial patterns are shown in the original article. But again, we don’t really know how they remember the patterns.

Overall, this is only preliminary research and MUCH more study, such as the mechanism behind all this, still needs to be done.

Posted by Hanbing Guo (2)

Betta, Betta, Betta


Last weekend my roommate and I decided it was time for a pet. We agreed that a Betta fish would be a good addition to our room. Betta fish, also known as Siamese Fighting Fish, are a common household pet. My roommate and I were inexperienced in Betta care. I was aware of the common fact that two males will fight each other if put in the same tank, but I was curious to what other behavior these little creatures possessed.

When we first brought “Henry” home he was very skittish. He could dart across the tank in less than a second. Betta fish are found in small, shallow streams in Southeast Asia. They face many predators and thus one of their defense mechanisms is being able to dart quickly through the water.

In terms of their fighting behavior, these fish are just doing what most male species do; protecting their territory. Why then do Betta’s get a bad rap for their aggressive behavior? It has been said that this behavior was bred into them. A tribe in Southeast Asia (called the Bettahs) would fight betta fish, for money in underground playing arenas, much like dog fighting. Historians argue that the Bettah tribe would fight the fish to test their bravery, and not to watch one of the fish die. The fish that survived a single fight would then be pampered and used for breeding for the remainder of it’s life. The past century society started marketing and selling the fish as pets, the behavior stayed. It is argued that this behavior was “nurtured” into the fish, and not instilled at birth. Wild Bettas do not fight to the death. When one of the males has seemingly won, the other will retreat away. When the domesticated Bettas fight to the death, it is due only to the interference of humans centuries ago.

Another interesting behavior about the Betta fish is that it has a special organ called a labyrinth as the top of its head. This allows the fish to take oxygen directly from the air, as well as with its gills. Henry often swims to the tope of the fish bowl, in fact he rarely “hangs out” near the bottom of the bowl. Bettas need to be able to reach the waters surface in order to survive.

A couple days after we got Henry, weird bubble nests started forming at the top of his tank. These were due to male Betta reproduction. When males are trying to mate, they will from “bubble nests” with their saliva that float to the top of the tank. They then will mate with a female, and the fertilized eggs will float to the nest and “snuggle” in there. The male will guard the nest until the younglings hatch. As to why Henry was making bubble nests is beyond me, poor guy there’s not a female around for miles!

Mia DiFabbio (2)

http://en.wikipedia.org/wiki/Siamese_fighting_fish
http://ezinearticles.com/?History-And-Background-Of-Betta-Fish&id=427181

UPDATE!!! ( 9.29.08)
Thanks for the interesting questions. Many of you expressed interest in the "bubblenest", based on the information I have found, domesticated Bettas do not have a fixed reproductive cycle. The males will make bubble nests when they are happy. In saying this, if you or your friends Bettas are making bubble nests you are doing a good job! It shows that they are healthy enough to want to mate, and it shows they are comfortable in the enviorment you have provided for them. In terms of other fish that have a Labyrinth organ, I have enlisted a site that shows pictures of various species. Most fish that have this, are tropical.

http://animal-world.com/encyclo/fresh/anabantoids/labyrinth.htm

 Digital Camo will Make Deer Hunters Invisible

Hunters may be given an extra advantage over deer soon.  If you are unfamiliar with traditional hunting camouflage, it can best be described as a brown and leafy green pattern meant to blend the wearer into a woodsy background.  It is very convincing—to human eyes.  But what do deer actually see?  Extensive research into ungulate vision and U.S. military concealment technology have come together to create Optifade, new hunting gear that claims it can render hunters invisible to deer’s eyes.

            Jay Nietz, of Medical College in Wisconsin and his team of colleagues have spent decades doing vision tests on notoriously shy deer.  The researchers tested their vision by showing their subjects three cards, and rewarded them with food when they selected the right pattern.  Nietz discovered that deer vision is a little bit blurry, at about 20/40.  They also have what’s equivalent to red/green colorblindness, with only two color receptors to our three.  Deer are more sensitive than humans on the blue end of the spectrum, and have a 270-degree field of vision, due to eyes on each side of the head.

            Timothy O’Neill, a creator of the pixilated digital camo used by the U.S. army today, describes Optifade as specific to deer eyes, and claims the patterns blend the wearer seamlessly into the background.  “This new camo…fools the deer’s vision system at its roots”.  At Hyperstealth Biotechnology, computer generated algorithms create fractal patterns that will be used for the camo.  Though being developed in state of the art computer labs, Optifade also owes some of its effectiveness to tricks borrowed from top predators.  The camouflage works in two ways:  micropatterns that blend into the background, like the spots on a leopard, paired with micropatterns that break up the wearer’s shape while in motion, like the stripes on a tiger.  Optifade camouflage will soon be marketed by W.L. Gore, of Gore-Tex fame. 

 Soon hunters will be disappearing in front of deer's eyes.  Doesn't it seem like a lot of money and effort went into outsmarting an already defenseless animal?

 Read  about it here.

Update, 9/30/2008:

Thanks for all the great comments.  I would like to clear something up:  When searching for an article to use, this one caught my attention, though I was hesitant to use it because, as a few of you mentioned, it does not have much on the behavior of the deer.  But I was still interested, so I asked Prof. Houlihan if it was a suitable topic.  He said it was, and to think of camouflage as predator behavior.  With that in mind, I found it interesting the comments made about the reality of camo as less about animal response and more about human response.  It is true that deer cannot see blaze orange on account of their color-blindness, making it effective for communication with other hunters rather than their prey.  As for scent and hearing, many hunters use products marketed to minimize scent-detection, and practice staying silent and still.  

Unfortunately, i could not find much additional information about the methods of the vision tests done on the deer.  I was curious about it myself.  

A video by Gore about Optifade.

Posted by Jane de Verges (2)

Understanding and using trade-off behaviors to help migrating birds

To determine stopover sites based on trade-offs between foraging opportunities and predation risks, the authors used Western Sandpipers (Calidris mauri) as their research species. These birds migrate between Peru and northern Oregon with stopovers at Georgia Basin (British Columbia, Canada) and Pugent Sound (Washington, USA). It is thought the birds use visual clues to determine quality foraging sites. The invertebrates the birds eat live in mud- and sand-flat environments that are easily spotted while flying. The birds follow the same route year after year and can change their stopovers depending on energy reserves and quality of site. Raptors are the main predator for this species. The raptors use tree and brush cover to surprise the unsuspecting migrants. Better quality sites would be those that are large open areas with minimal cover and abundant foraging opportunities. Poorer quality sites are those that are small open areas with lots of tree and brush cover providing hiding spots for raptors. Thinner birds have to endure poorer quality sites because they can not fly as far or compete for prime feeding areas with birds that are in better shape. By using feeding vs predation behaviors as factors in determining stopover sites the authors were able to predict which sites the birds would most likely choose on their migration to and from their breeding grounds in Oregon.

I thought this was interesting because scientists are using two key behaviors exhibited by these birds to determine which sites would be more worthwhile protecting as habitat encroachment and global warming take-their-toll. No one has enough money to save all sites so we are down to protecting the most profitable ones. By understanding behaviors we are able to provide the most beneficial assistance to this species.

Posted by Allan Eldridge (2)

Ants Assign Assignments According to Age

Everyone has seen the complex metropolis known as an ant farm and many more know about the complex structural organization involving the queen, worker ants, soldier ants and so forth. But did you know that ants divide their tasks according to age, hereby increasing the colony's fitness? It's this evolutionary mechanism that scientists believe has been a major factor in the success of social insects.

Dawid Moroń, Magdalena Witeka, and Michal Woyciechowskia created an experiment in which they tested colonies of the ant Myrmica scabrinodis, to see if the colonies would reassign risky jobs to less fit ants. The students did this by creating living environments for small artificially created hives and by treating a certain number of ants with carbon dioxide, another group they surgically removed propodeal spines, and the rest they left as control. The carbon dioxide greatly damaged the nerve membranes and increased haemolymph acidity, while removing the propodeal spines "provided an avenue of infection and/or uncontrolled desiccation". Desiccation is a fancy word for extreme dryness. The results of their experiment were as they hypothesised; the poisoned ants and the injured ants all started working riskier jobs earlier than the control ants did. Instead of working inside of the hive, where the safer jobs are, they were instead chosen to forage for food, a dangerous activity due to predators, competitors, and parasites.

The experimental data supports the original hypothesis, even though the experiment is testing for weakened/crippled ants, because generally speaking, the older the ant the weaker the ant becomes. This is not to say that 100% of the elderly ants would all have the same symptoms as the poisoned/maimed ants; we're merely making supporting a correlation between them.

Unfortunately, we are hopelessly ignorant about the actual ant behavior that leads to weakened ants being sacrificed for the colony and how the colonies determine the "fitness" of an ant. However, we do know that having the less fit ants do the dirty work, makes for a fitter colony.

The original document can be found at http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4PT2FSP-R&_user=1516330&_coverDate=02%2F29%2F2008&_rdoc=4&_fmt=high&_orig=browse&_srch=doc-info(%23toc%236693%232008%23999249997%23679569%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&_ct=48&_acct=C000053443&_version=1&_urlVersion=0&_userid=1516330&md5=31d2a104a94d1acb6f33b2130c4dcace.

Posted by David Byun (1)
Edited by David Byun on 9/21/08 @ 9:30pm

Shimmering Repels Hornets from Honeybee Nest

Giant honeybees (Apis dorsata) have evolved an impressive looking defence mechanism that effectively deters one of their predators, the hornet. The behavior termed 'shimmering' involves hundreds of bees flipping their abdomens upwards rapidly in a wave that spreads across the surface of their open nest. Shimmering is not only a reliable survival strategy but it is one that involves very little risk on the part of the honeybee and consumes far less energy than sending out flying defenders or "heat-ball"ing intruders to death.

Small-scale waves prevent the hornet from being able to single out one bee and a failed attack results. As the number of bees involved in the wave increases the hornets turn further away from the surface of the nest and increase their speed of retreat. There is a definite limit to the level of protection that shimmering offers however. This limit is called the mean hovering distance and is determined by the experimental distance at which the hornet displayed an avoidance reaction to shimmering. Just as the hornets responded differently to the intensity of the shimmer the honeybees shimmer is a result of the location and speed of the hornet. A faster hornet in closer proximity to the nest elicited a stronger, faster wave pattern.

An important part of this process is the hornets inability to adjust its behavior to the repeated failings of its attacks. Shimmering stimulates a fixed action pattern of avoidance in the hornet that it is unable to habituate itself to.

The authors of this paper Gerald Kastberger, Evelyn Schmelzer, and Ilse Kranner also included this brief discussion of the pheromone cues of shimmering:

Stinging activities do not occur during shimmering, but otherwise,
alarm pheromones of honeybees do not prevent hornets from hunting bees [2], [17]. Second, shimmering is accompanied by the
release of Nasonov pheromone [14]. After a series of repetitious waves, Giant
honeybees open their last inter-tergital gaps of their abdomens, exposing the
Nasonov glands. Nasonov scent is a social pheromone and signals to the bees to
‘stay together’ [14], thus preventing single bees from changing
their roles into those of guard bees (flying defenders) that would fly off to
attack the predator. However, there are reasons that make it is impossible for
Nasonov pheromone to trigger the avoidance response of an approaching hornet.
Firstly, the exposure of Nasonov glands has been only observed after a series of
shimmering episodes [14], but hornets were disturbed by shimmering
from the first wave onwards. Additionally, and more important is that the
latency of the avoidance reaction of the wasp after the onset of shimmering is
less than 100 ms, and is therefore by several orders of magnitude faster than
the exposure of Nasonov glands and also faster than the obvious spreading of the
pheromone would take.

Posted by: Margaux Curboy (1)

Update 09/23/08:

Here are some videos used in the study to visually clarify the idea of shimmering.

Mexican Wave
New Scientist briefly explains four videos used in study.

Migrating Bird's Strange Sixth Sense
I thought this was especially interesting since it relates to what we have been talking about in class. An article in the October 2008 issue of popular science, found here, discusses a new theory as to how a bird is able to navigate over long distances. Their navigational abilities are in part due to "magnetite" in the bird's beak, which let them detect the Earth's magnetic field. But their ability to detect direction may be in part to a newly discovered compound, called a CPF triad located in the retinas of migratory birds. When a bird's eyes are lit up with a level of light similar to that found at dusk, the compound forms "two unpaired electrons that spin in oppposite directions." The Earth's natural magnetic field forces those unpaired electrons to align north, giving the birds a sort of natural compass. The birds may be able to actually see the planet's magnetic field. Henrik Mouritsen of the University of Oldenburg in Germany compares this system to the head-up display of a fighter pilot

Posted by Corinne Delisle
Week one


Edit 9/23
To answer some of the questions and comments, I searched online for other versions of this article that give a little more information. When the bird's retina absorbs light, a chemical reaction is triggered that produces a substance which is sensitive to the magnitude and direction of the Earth's magnetic field. Apparently this is supported by experiments in which blue light photoreceptors have been found in the retinas of birds. "CPF" stands for "Carotenoid Porphyrin Fullerene". These are the molecules that are linked to form the triad. Each triad unit contains a pair of electrons with a neurtal pair of electrons in the ground state. When the molecule is exposed to light, a reaction occurs and the poryphyrin is promoted to an excited state. This starts a kind of chain reaction, the result of which is the CPF molecule existing in a charge seperated state. The unpaired (charged) electrons are then able to react to a weak magnetic field.

Picture Credit: Zina Deretsky, National Science Foundation

(This information came from this webpage.)

To answer the question about Hund's rule, all electrons in singly occupied orbitals have the same spin. For example, I think there are 5 3D orbitals. If there are five or less electrons among those orbitals, they will spread out and all will have the same spin. But I believe when a pair of electrons share an orbital, then they have opposite spins. For example, there is only one 4s orbital, so the electrons can't spread out. One electron in the orbital will have an "up" spin, and the second will have a "down" spin.

Fruit Flies and Community Influence

Initially, I believed that fruit flies, like any other readily used lab insect, were very simple beings. I thought that their only intentions while they lived were to eat and survive long enough to reproduce and pass on their genes. I never would have thought that fruit flies would have had any social behaviors at all within the species. I actually thought they're whole lives were just fixed, but I was certainly wrong.

Recent studies dealing with fruit flies consisted in the observation of a single fruit fly's behavior isolated from any other fruit flies and then its introduction to a group of fruit flies. Apparently not only the behavior of the fruit fly changed within the first day of group introduction, but also the physiology and, even more interestingly- gene expression. This reminded me of the situation of the House Sparrows that I learned about in my animal behavior class. In the case of the house sparrow, when a male is around other males, that male may be treated differently in accordance to the size of the black chest badge he bears. In being treated differently, the male sparrow may produce more testosterone (if his chest badge is on the 'larger' side of the population's badges) due solely to an environmental cue.

One experiment done with the fruit flies consisted of observing flies similar at the genetic level in a group as opposed to flies variant at the genetic level. The results showed different chemical signals from the fruit flies in the genetically similar group than from the genetically different group. This experiment strongly supports the change in gene expression of a species due to an environmental/social cue.

Further observation of the fruit flies showed that the flies in the more genetically mixed groups mated and reproduced more than the fruit flies in the genetically similar groups. This gives more information about the sexual behavior of the fruit flies and could lead us to believe that the fruit flies may be interested in varying the diversity of their genes by mating with a partner of unalike features. In addition to the discovery of the increased sexual activity, the experiments performed displayed that the response of an individual male to fruit flies similar to himself depends on his neighbors- the other flies also present at the situation. The response, including chemical response (release of pheromones) given by that male fly was dependent on the peer's of the male fly, and therefore we can conclude that behavior is not only dependent on molecular signals, but also an element that contributes to the control of chemical signaling.



-Kiel Boutelle
-Bio 550 Section 1

Wren Duets – For Togetherness or War?

For years, it has been known that wrens sing duets with their mates. Recently, the availability of new technology has allowed researchers to figure out the purposes behind the songs.

Studies were conducted using a series of microphones which were used to listen to the songs and calculate the birds’ positions. This technology eliminates the need to capture and tag birds, or even be able to see them in the dense forests that they inhabit.

As it turns out, the birds use duets like children play “Marco Polo”. One bird will begin to sing and then, upon hearing its partner’s half of the song, it can figure out its mate's location and move toward it.

The duets also have another purpose. As found by this study, when one pair of wrens hears the duet of a rival pair in their territory, the songs are now used as battle cries. At the arrival of the new pair, the frequency of the duets increases dramatically. If the songs fail to ward off the intruders, physical violence can incur.

This research has proven the value of the new multi-microphone technology. Because of this, scientists hope to use this technology to uncover behaviors of others species that also sing duets.

The full article can be found here.

Listen to the duets.

Posted by Allison Cornell (1).


Updated 9/23/08:

To answer some of your questions, I searched for another article. (The website I found also has more samples of the wrens’ songs.) I discovered that males and females each have a set of songs they sing, specific to their gender. The set of songs among different females are similar in pattern and song structure, but vary slightly between different birds. The same holds true for males. As for the gender roles in these duets, both the males and the females initiate them. Therefore, it is not always the same one calling first every time.

Post Update by Allison Cornell (1).

Socially Learned Behavior; Essential for the Survival of Many Living Species on this Planet

There are various behaviors that different societies and cultures deem appropriate or necessary and these behaviors are essential to understand and know when to apply and use for the survival of many species within that society. For example out culture frowns upon walking down a main road naked, or shooting guns at crows in your backyard with neighbors close. Not following these rules can make for a very difficult life and even in some cases can result in death. learning when and where to apply certain behaviors is typically taught to many organisms by either their parents or by the community that they belong to, but they are always taught these values during ontogeny.

In the case of Black Bears (Ursus americanus) this method for raising offspring applies in the same way. For the black bears of Yosemite and Sequoia National Parks the ability for cubs to learn where and what to forage can be result in much more drastic consequences (death) if the offspring are taught improperly or not taught at all. For many of the park rangers at both Yosemite and Sequoia National Parks the bleak and raw results from improper foraging are a rather common situation.

Rachel Mazur and Victoria Seher along with the help of many park rangers conducted a study of the effects of sow cub foraging behaviors during 1995-2006 at Yosemite National Park and from 2000-2006 at Sequoia National Park. Of the 99 cubs reared during this period 20 were raised by mothers in exclusive wild areas and 18 remained in wild conditions throughout their life. 31 cubs were raised by mothers who themselves had been known to forage in developed areas although they taught their offspring to forage in wild areas. The remaining 48 cubs were raised by mothers who foraged in developed areas. Of the 51 cubs raised by mothers in wild conditions 44 remained foraging in wild conditions as adults and of the 48 raised foraging in developed conditions only 9 foraged as adults exclusively in the wild.

It is obvious that offspring pick up habits and social behavior from their parents (in this case just their mother) although not always can this be a good thing. Of the 48 cubs that were taught to forage in developed areas 22 died before they were 2 years old. The implications of this data are that there needs to be more effort put into the negative reinforcement of black bears when they are found to be in developed areas. Currently there is more efforts to increase the harassment towards black bears in developed areas, but some of this harassment needs to come from citizens , making loud noises or spraying bear spray are both ways that everyday people can help in this tragic situation. So now you know carry bear spray, not only can it save your life but you can help save the lives of bears.


Posted by Joe Alonzo

article can be found at: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4RYXST3-2&_user=10&_coverDate=04%2F30%2F2008&_alid=792761296&_rdoc=2&_fmt=high&_orig=search&_cdi=6693&_sort=d&_docanchor=&view=c&_ct=17&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=166f050f394949a407acfd8e07c039fe


Updated.

in response to Tara Quist:

Many of the cubs forage based on both the environment and from what they are taught by their mothers, for example they are taught to eat out of dumpsters and trash cans which they are comfortable doing for the majority of their upbringing. Then one day they go through some traumatic event which makes them think twice about eating out of those ares, maybe a human almost hitting them with a car, or a gun being shot at them or worse their mother being killed in front of them. In this case they would probably resort to foraging back in the wild. Although the opposite could happen and the cub could go throughout their entire life and never go through an event like the above one and therefore always forage in developed areas.

many comments wanted to know about the cause of death for many of the cubs:
of the 22 who died before the age of 2, 16 died in or around developed areas by the following methods:
8 were hit by cars
1 killed inside of a garbage truck
1 killed by stoning by visitors
1 drowned in a sewage pond
5 were killed by park management for public safety

In response to Cecelia Hunt:

I think that cubs can pick up on stress from their mothers, so if they are being taken into stressful situations that cause a lot of tension (developed areas) the rewards better be worth it. For some of the cubs the rewards aren't great enough for them to risk their safety and so they choose to forage back in the safety and familiarity of the woods, this is the reason that I think some of the cubs raised in developed areas choose to revert back to the wild for their food. That and a combination of what was stated above in response to Tara's question.
No there was no control used for this study, only bears at Yosemite and Sequoia National Parks.

Response to James Sullivan:

Yes, if you see bears in developed ares use negative association tactics to make the bear leave. Scare them, yell, scream, make a lot of noise, throw things at them whatever it takes get them to leave and try to install a sense of danger and fear so that they associate development with danger and fear rather then with food and gluttony.


-Updated by Joe Alonzo

No prints left by early foal training sessions

Lots of horse trainers and breeders stand behind the idea of imprint training their foals. Imprint training is a desensitization process that begins shortly after the birth of a new foal. There are many was to go about this training but most methods include rubbing a foal all over, lifting its feet and exposing it to sprays and plastic bags. The idea is that early exposure and desensitization will help the foal cope with these in the future and make them more manageable and calmer when further training begins.

This study takes all the foals on a farm from a given breeding season and about half are put through imprint training methods form the time they stand and nurse. Training sessions are given at this time as well as after 12, 24, and 48 hours after birth. Foals in the control group are not handled. After this initial training al the foals are tested at 1, 2 and 3 months of age. Their acceptance and tolerance are measured on a given scale to see how the early training has helped. In all the tests, including haltering, attaching a heart-rate monitor, and introducing novel and previously shows stimuli, the imprinted foals showed no more acceptance of the tests. In the tests where the behavior (lack of rejection) was rated there was no notable difference between the control foals and the imprinted ones.

While imprint training has long been a staple in large breeding farms this study has found no real advantages to the method used (which was one of the widely accepted procedures). Some variations of the training can be more successful, but the reasons might not be because of the early start but more of the repetitive nature of the training. While the affects of imprinting may be obvious in other animals, such as birds, this early life training in foals doesn’t seem to be as important as steady, reinforced training over time.

Posted by: Erica Damon (1)

Ever think of a fruit fly hanging out at the bar trying to “pick up” another fly?

Sure some people change their behaviors around certain people, but surely that only occurs in humans. Think again. According to neurogeneticist Joel Levine, of the University of Toronto, “insects alter their behavior depending on who they hang out with, even mating more frequently in the company of strangers.” This new research is providing more clues on the evolution of social behavior.

Fruit flies obviously do not talk, but they emit 23 identified varieties of pheromones, which the flies can blend into various combinations to “say” or mean something different. They also change their behavior patterns and sleep patterns depending on the “number and relatedness of the other flies they are with,” leading Levine to experiment with these insects to further understand what is influencing this reaction. In their first experiment they divided the flies into vials of forty males, with some vials containing nearly genetically identical flies, and others containing a mixture of genetically identical flies and non-genetically identical flies. The outcome of this experiment led them to believe that the “pheromones important for courtship and mating were affected most by the social context…how a fly reacts [pheromone-wise] to another fly depends on who he has been hanging out with.” Sounds like a very familiar situation that occurs almost regularly in the human population. Others’ behaviors effect how one reacts.

In his other experiment, he tested whether males in mixed groups would behave different in the presence of females. In some vials he had six genetically identical males with six virgin females, while the other vials had four genetically identical males, two different males and six females. What Levine found was that the flies that were in with males unlike themselves sent them into “sex overdrive: they mated 33% more often” than the other set of flies. This is showing that fruit flies are sensitive to their environment, and that mating behavior may not be as hard-wired as once thought; indicating the discovery of plasticity in this behavior. So after all maybe we are just like fruit flies in the aspect of social behavior.

Posted by: Katie Cole (1)

Those Pesky Flies

Most people would have to agree, trying to hit and kill a fly can be a challenging business. Michael Dickinson, a professor who researches the biomechanics of insect flight at the California Institute of Technology, has recently discovered why flies are so hard to swat. Dickinson used high-resolution, high-speed digital imaging to record the flies reaction to being swatted at by a 14-centimeter-diameter black disk. What he and his graduate student, Gwyneth Card, found was that in about 100 milliseconds time the fly is able to not only calculate the direction and angle that the threat is coming from, but also to orient its body in the optimal direction for takeoff before it flies off unscathed. "This illustrates how rapidly the fly's brain can process sensory information into an appropriate motor response," Dickinson says. The fly was also found to be able to make “planning movements prior to take-off” and adjust It's movements according to the position it was in. Once again, in only 100 milliseconds,

“The fly must integrate visual information from its eyes, which tell it where the threat is approaching from, with mechanosensory information from its legs, which tells it how to move to reach the proper preflight pose. This means that the fly must integrate visual information from its eyes, which tell it where the threat is approaching from, with mechanosensory information from its legs, which tells it how to move to reach the proper preflight pose."

It is suggested in the article that there could be “some sort of map in which the position of the looming threat is transformed into an appropriate pattern of leg and body motion prior to take off”. These findings remind me of the owl and its kidney shaped optic tectum. It seems to me that because the fly is able to accurately adjust to the angle and location it is being swatted from, that there could be some part of it's brain where neurons are laid out as some sort of spatial map that will rapidly fire neurons connecting the visual input from the flies many eyes to its legs and body. Also, the fly is able to respond so quickly, and in the appropriate direction that it seems strikingly similar to the crayfish's ability to move it's tail in response to an attack. This makes me wonder if the neurons involved are large in size to allow for such a fast reaction time. Dickinson said, "This is a rather sophisticated sensory-to-motor transformation, and the search is on to find the place in the brain where this happens."

This press release was found on the Caltech Media Relations website. Dickinson's paper, “Visually Mediated Motor Planning in the Escape Response of Drosophila," will be published August 28 in the journal of Current Biology.

Posted by: Rachel Carboni (1)

The Nocturnal Robins

When scientists first noticed that robins in some urban areas were singing at night rather than singing during the day, they concluded that pollution and bright city lights were to blame. “It was thought that street lights tricked the birds into thinking it was still daytime,” says BBC News Science and Nature reporter, Mark Kinver. One thing is certainly for sure. Something is occurring in our cities that are making these birds sing at night. Richard Fuller, a co-author of the published findings that inspired Kinver’s article states, “You generally only seem to hear nocturnal singing in cities.”

Eventually further research revealed that perhaps a high level of noise was to blame for the late night singing. Scientists discovered that “Noise levels were 10 times higher in places where birds were singing at night” (Fuller). But, why? According to Fuller and his fellow researchers, the birds now sing at night because the day time city noise is just too much competition for the small robins.

It seems unclear if this switch to nocturnal singing has or will have any effect on the overall fitness and well being of these urban robins. Time will tell! To read the entire article from BBC News, click here.

For those of you who are interested in finding out more about this phenomenon and the possible effects on these birds, here are a few more sites to check out!

http://www.guardian.co.uk/environment/2008/jun/29/wildlife.animalbehaviour
http://www.nytimes.com/2007/05/08/science/08observ.html

Posted by: Ericka Adey (1)

Those Clever Crows

An article published in National Geographic about a study done by Nathan Emery and Nicola Clayton reveals that crows and some other birds from the corvid family may be as intelligent as primates. Although they hold a different brain structure than primates, they are able to use similar cognitive skills to solve problems. It is hard to visualize, but some of these skills include using their imagination and the ability to anticipate the future. It is also thought they may be able to use memory to help them in certain situations. Scientists also noted that brain size in crows and other corvids is comparable to that in primates, relative to their body size.

Because crows are very social, and live in large groups, scientists say that the use for these skills comes out of social necessity. They also compare this kind of social interaction to dolphins, chimps and humans.

As an example of the crow’s intelligence-
First of all, crows have figured out how to crack nuts by dropping them from a high distance onto the pavement. Because this some times takes quite a while, they figured out that they can drop the nuts from the sky into speeding traffic, allowing the passing cars to crack the nuts. The cleverness doesn’t stop there. They have also learned that by dropping them in a pedestrian crosswalk, the passing cars can still crack the nuts, but there is also a safe manner for the crow to retrieve the goods. When the traffic light changes and the crosswalk light comes on, the crow swoops down and gets the cracked nut. Now that’s a clever crow!

See this video from YouTube of crows using the traffic light.

Crows have learned to use tools. They have been known to make hooks from twigs and branches to retrieve insects from their holes. However, this has also been documented inside a laboratory where a crow used a metal wire to retrieve food.

See this video from YouTube of a crow using tools.

There has been some other research from Emery and Clayton that may reveal that the tool making in crows may differ among cultures. For more reading on this subject, please see:

Cultural Tool Use in Crows

See the entire article here:

http://news.nationalgeographic.com/news/2004/12/1209_041209_crows_apes.html

Posted by: Michele Copeland (1)