http://video.nytimes.com/video/2008/11/17/science/1194833211431/americas-disappearing-forests.html?
scp=1&sq=america's%20disappearing%20forests&st=cse
Reports of animal behavior research and personal observations by the brilliant students in Biology 550.
I’m sure you’ve seen the movie Gremlins, and if you haven’t, I know you must be familiar with what Furby is. It has just been released that creatures called pygmy tarsiers were found on an Indonesian island. These little guys haven’t been seen alive by scientists since 1921, and were thought to have been extinct. The cool thing about the pygmies-they are primates!
Is it the end of the Tasmanian devil?
Bumblebee colonies which are fast learners are also better able to fight off infection, according to scientists from Queen Mary, University of London and the University of Leicester.
these scientists tested the learning performance and immune responses of bumblebees from twelve colonies.
The team tested the ability of 180 bees to learn that yellow flowers provided the biggest nectar rewards, and to ignore blue flowers. To test the evolutionary relationship between learning and immunity, they also took workers from the same colonies and tested their immune response against bacterial infection.
Like humans, bees’ ability to learn appears reduced when they are ill. The prediction was that good learners would be worse at fighting infections – but surprisingly, this was not the case.
the team reported a positive relationship between a bumblebee colony’s learning performance and their immune response. Bees from fast learning colonies are not only the best nectar collectors, but also better able to fight infections. These colonies are probably much better equipped to thrive under difficult conditions.
The team expected that immunity is likely to be a really important trait in social species (like bumblebees, honeybees and ants) that have high-contact rates with closely related individuals leading to a greater chance of infection.
The team found a positive correlation between the ability of a colony’s workers to learn and the strength of their immune response, so there was no evidence for an evolutionary trade-off between these traits. These essential pollinators learn many things in their short life and fight off a range of infections to survive.
Hessom Minaei (10)
update
As nectar levels in flowers change from minute-to-minute, faster learning bees are more likely to keep track of which blooms are most rewarding, and thrive as a result. Dr Nigel Raine and Professor Lars Chittka from Queen Mary’s School of Biological and Chemical Sciences presented these bumblebee colonies with flight arenas containing blue and yellow artificial flowers, which were stocked with different amounts of nectar reward. The bees were challenged to overcome their natural preference for ‘blue’ flowers, and to learn that the ‘yellow’ flowers were more rewarding. The team found that the colonies which learned colours quickly, were more successful foragers. Rather like us, some bees learn from their mistakes more quickly than others. These faster learning bees also collect more nectar from flowers, which ultimately means their colony will be more successful.
Turtles Change Nesting Dates Due to Change in Temperature
Crabs That Have To Act Tough
Male fiddler crabs can be recognized by their huge claw that is used to defend and intimidate other crabs. These crabs live in burrows and their enormous claw has a large role in the defending of their territory. Often, crabs will lose their claw in a battle over a burrow with another crab. These claws do grow back looking identical to their original claw but are not as strong. The crabs recognize that the new claw does not function as well as it’s previous claw had.
Even with this disadvantage, a crab with a new, weaker claw will act as nothing is wrong when faced with a new opponent. The fiddler crab will show it’s claw in a threatening manner as a bluff in order to defend or steal a burrow. A group of researchers collected a sample of these fiddler crabs, Uca mjoebergi, with new claws near
Crabs that were released with the second claw and unable to find an uninhabited burrow generally tried to intimidate smaller crabs out of their burrows. The small crabs fell for the bluff most of the time, vacating the burrow. On the other hand, crabs that had the new claw that were invaded by crabs with an original claw were forced to bluff and if necessary defend the burrow. Since the new claw is much weaker than an original claw these crabs generally would lose if a fight broke out. This shows that the crabs with a new claw were much more successful at bluffing and invading a burrow rather than trying to defend one.
Click here for the original article “Crabs That Fib,” by Kelly Whitlock Burton.
Rob Lubenow (9)
Rightys and leftys can’t mate??
Imagine being told that just because you were left handed you couldn’t mate with a right handed person. This is apparently true in pond snails, which not only are believed to have brain ‘handedness’ but they are physically unable to mate with another snail whose handedness differs from their own.
Hayley Frend, a student studying the sex life of pond snails has shown through her research that invertebrates too have behavioral handedness. One of the behaviors which is mating is thought to be pre-programmed from the mother’s genes. The pond snail starts mating by moving in small circles and depending on handedness depends on which way you move. Two snails of opposite handedness will usually make mirror images of each other and be unable to mate. Like humans left handedness if much less common and unfortunately for the lefties of the snail world they have a much smaller pool of mates to choose from.
Article found here
Amanda Joyce (week 9)
"chew up rattlesnake skin and smear it on their fur to mask their scent form predator,.."It seems that mostly female and their young ones, just like the use of heated tail, use this behavior of chewing chewing rattlesnake skin. The squirrels don't just use rattlesnake skins, they also use anything that has a snake's odor. She believes that by chewing and spreading the rattle snake skin on their own fur, the squirrels are about to hind their own scent with the rattlesnake scent. By doing so the squirrels are about to sleep a little bit more peaceful at night.
For decades, homosexual behavior observed in male flour beetles has perplexed animal behaviorists. The beetles, 3-millimeter long Tribolium castaneum, found in temperate areas, have been the focus of several studies in an attempt to solve the mystery of their homosexual tendencies. From an evolutionary perspective, homosexuality is counter-productive to the species’ fitness, though it has been observed in many animals, including insects, penguins and primates. There are several theories to explain the phenomenon. Some scientists believe the males copulate with other males as practice before attempting to mate with females. Others suggest that the males need to get rid of old, less effective sperm before mating with females. Other scientists have even suggested that homosexual behavior is a way of exerting social dominance over other males. A new study threw a wrench in these hypotheses.
The study, headed by evolutionary ecologist Sara Lewis, of Tufts University, began by marking male and female flour beetles. The team tracked their individual sexual exploits, while monitoring the paternity of any offspring born in the group. Their results showed that homosexual encounters did not improve the male’s sexual success with females, and found no connection between homosexuality and social dominance. What they did find came as a shock: the sperm leaked by one male onto another during homosexual encounters could actually inseminate a female who later copulated with the second beetle. In other words, a beetle could inseminate a female without directly breeding with her. This proves the beetles’ homosexuality a reproductive benefit, as the males can inseminate females without spending the energy necessary for finding and mating with them. The results were so surprising to the researchers, that the experiment was repeated several times, with the same results. This research is a triumph for evolutionary biology, as homosexuality in animals is often written off as confusion, and is rarely explored objectively.
Update: (11/11/2008)
Though zoologists often avoid the topic for fear of crossing into political debate, the fact is that homosexuality has been observed all across the animal kingdom, in captivity and in the wild. It has been observed in insects, birds, sheep, fruit bats, dolphins, apes and monkeys. At the New York Central Park Zoo, two male penguins named Ray and Silo have been displaying classic pair bonding behavior for 6 years. This behavior includes entwining of necks, mutual preening, flipper flapping, and mating, while ignoring females. In the wild, some male ostriches only court their own sex, and pairs of male flamingos have been known to build nests and raise foster chicks. Homosexuality in females has been observed in Japanese macaques, though scientists are still unclear on the reason. It is possible that these relationships have an unknown adaptive pay off, or they could just enjoy it. In bonobo apes, a close relative of humans, 75% of all sex is non-reproductive, and almost all bonobos are bisexual. Scientists believe that the bonobos use sex to resolve conflicts in the group. Temporary homosexual partnering in immature dolphins is believed to be a way to form lifelong bonds. Explaining he mystery of homosexuality in animals has only begun. Robin Dunbar, a professor of evolutionary psychology, argues that homosexuality may be a by-product of something else and hold no evolutionary function at all.
-Jane de Verges (8)
Calculating diabetes risk by observing environmental behaviors
Diabetes type II is a disease inherited from parents and passed on through genes to their offspring. Genes can be influenced by an organism's relationship to its environment. In an article from Science Daily scientists are considering the effects of mice interactions within their environment when trying to determine the risk of catching a disease like diabetes. The authors of this study looked at glucose tolerance in order to determine diabetes risk in two different species of mice that are closely related but behave and live very differently. One of the things observed by these researchers was that just handling the mice to perform the experiment resulted in significant blood sugar level changes. The study indicates that calmer male mice have higher levels of stress hormones and maintain their blood sugar levels a lot better than less calm male mice and females of both species. The scientists were also able to show that genetic variation of the Y chromosome was responsible for a specific response to stress of the observed male mice. How well mice are able to handle stress and regulate blood sugar levels could also help determine whether a mouse will be monogamous or not. This conclusion was reached by the UC Irvine scientists.
This study helps to illustrate the importance of considering an organism’s relationship to its environment as well as its behaviors when attempting to understand disease risk.
Allan Eldridge (8)
Blood Sucking Vampire Bats Sing Duets