Platypus Electroreception

What do you call a cat-sized, venomous, egg-laying semi-aquatic mammal with the bills of a duck, the tail of a beaver, and the feet of otters? When European naturalists first encountered the platypus, they thought that it was an elaborate conspiracy against science. All oddities aside, platypuses are ones of the only mammals that are able to use electroreception (the only other one is the echidna, or spiny anteater). The platypus has the most sensitive sense of electroreception out of all the mammals, and the receptors are located in their bills. They swim in a characteristic side-to-side motion because they are able to determine the direction of any electrical source (this, of course, works better in water). Electroreceptors in the bill are coupled with mechanoreceptors to perceive both electric signals and tactile ones. Tiny pressure pulses are detected by the bill, which direct the platypus to its prey. To feed, the platypus will dive to the bottom of the stream and dig with its bill. When tiny electrical signals are detected by the muscular contractions of organisms are detected, it will then close in on its prey. Experiments with robot shrimps sending out electrical signals have also triggered this response. These mammals are unique in that it feed by neither sight nor smell. They also possess spurs in their hind legs that inject a venom causing tremendous pain to mammals as big as humans. They also store food in their cheeks while preying, similar to squirrels. These mammals make centaurs and unicorns look normal.

http://www.animalcorner.co.uk/venanimals/ven_mammalsPlat.html

Posted by Michael Shi

Lyre Birds

http://www.cracked.com/article_19483_5-birds-with-abilities-that-put-superheroes-to-shame.html

So I know the link I have above isn't the most scientific reference , but this bird is quite fascinating. The Lyre bird is able to mimic any sound it hears. This is truly remarkable considering we went through examples a couple weeks ago where if a bird does not hear the correct song, the song can get distorted. The lyre bird's main song is a mixture of seven elements of its own song and any number of other mimicked songs and noises. They are able to mimic other animals as well such as koalas and dingos. The lyre bird's have the most complex syrinx compared to other songbirds. This allows for it to have unmatched mimicry. Lyre Birds will hear any noise and incorporate those notes into their songs.

The question then remains , how is it that the lyres are able to process all these notes and still be able to recognize their own species calls. Since each lyre may hear different things, each song must be very unique from each other.

Posted by Jobin

Poison frogs color evolution

Individuals of the same species, poison dart frogs, can vary greatly as far as color patterns go. Color patterns seen in a population depend on where the frog lives.

Researchers from the University of Montreal performed a study in Peru using decoy frogs. They placed 3,600 clay frogs painted three different colors in different spots.

"In the highlands of the Cainarachi Valley there, the frogs are splashed with a green undulating pattern, almost like an abstract snakeskin pattern. In the lowlands only 6 miles (10 kilometers) away, the same species of frog boasts yellow stripes instead."

Frogs that had been painted to look like locals were much less likely to be attacked by predators, because the predators know frogs marked like that are poisonous. Frogs of the same species with different color patterns were twice as likely to become prey. Because the local frogs are known to be poisonous they are not chosen as prey and and much more likely to reproduce, spreading their color pattern.

The fact that color patterns varied so much in populations so close together I found particularly interesting. Also, the rate at which the predators learned that the decoy frogs do not make a good meal was also very surprising, as most of the attacks on the decoys had happened within a day of them being placed.

Source: http://www.livescience.com/17138-poison-frogs-color-evolution.html

Posted by Emily Nobrega

SEX WITH A BEER BOTTLE?

Beetles are dying while trying to get it on with discarded brown beer bottles, according to research conducted by Darryl Gwynne, a University of Toronto Mississauga professor.

It's a case of mistaken attraction, because the beer bottles happen to possess all of the features that drive male Australian "jewel beetles" wild. They're big and orangey brown in color, with a slightly dimpled surface near the bottom (designed to prevent the bottle from slipping out of one's grasp) that reflects light in much the same way as female wing covers. As a result, the beer bottles are irresistible to the male insects, which will die trying to mate with them in the hot Australian sun.

The bottles resemble a "super female" jewel beetle. Male beetles are so captivated by the bottles that they will gird their loins and go through the expected motions, refusing to leave until they fry to death, are consumed by hungry ants, or are physically removed by researchers.

The male beetles are very particular about the bottles. Beer cans or wine bottles do nothing for them. It's all about the shape, color and texture and has nothing to do with booze. As the researchers wrote in their findings, "Not only do western Australians never dispose of a beer bottle with beer still in it, but many of the bottles had sand and detritus accumulated over many months."

While the researchers obviously see the humor in all of this, there's a serious message too. The findings demonstrate how our garbage not only litters landscapes but can also directly affect the populations of other species. This also points out that the research supports a theory of sexual selection: that males of certain species, in their eagerness to mate, are often the ones making mating mistakes.

http://news.yahoo.com/why-beetles-sex-beer-bottles-q-scientists-200203561.html

Posted by Whitney Huynh (8)

Spiders give gifts and fake death for sex!

As we’ve started talking about sexual selection in class, I find it fitting that this week’s blog be about that very subject. In class, we mentioned how the male scorpion fly presents ‘gifts’ to the female, usually a dead bug, in order to distract her so the male can copulate for an extended period of time. Well, as it turns out, these flies aren’t the only one paying for sex. Pisaura mirabilis, also known as the nursery web spider, is European species who also present ‘gifts’ to females in order to distract them so they can copulate. While most males present fresh prey wrapped in silk, some just wrap shell husks in silk and present. Scientists believe the stress of finding a mate forces these males to present anything in order to have a longer copulation time. Researchers from Aarhus University in Denmark and the Instituto de Investigaciones Bioloìgicas Clemente Estable in Uruguay took 20 spiders and set them in groups and gave them gifts to wrap: either no gift, a shell husk, a fresh fly, or a protein-enriched fly. They found the males would wrap the present with silk until it was unidentifiable, giving them more time for copulation as the females would inspect the gift. As expected, males who presented gifts had greater success mating, and those with edible gifts got to mate for a longer period of time. What separates these spiders from other gift-giving species is the other trick they use to mate. If they haven’t copulated for a long enough time, some males will pretend to die, with their gift in hand. The females would then drag the male ‘carcass’ along in order to try to take the gift. Once they stop dragging, the males will revive and mate with the females for a second time (talk about desperate). This feigning death is called thanatosis. And we think human men can pull some weird crap when trying to get a girl.

Picture of male spider giving gift:


Information came from the article “8-Legged Sex Trick? Spiders Give Worthless Gifts, Play Dead” written by Jennifer Welsh on Nov. 13, 2011 from livescience.com. Link:
http://www.livescience.com/17010-spider-gifts-play-dead-mating.html

Posted by Austin Gray (8)

RIP Western Black Rhino

The International Union for Conservation of Nature, otherwise known as IUCN, is an organization that is responsible for collecting the data on endangered species throughout the world. IUCN uses a classifying system to rate the status of a species. This system has ratings such as Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct. Using certain criteria, the IUCN is able to assess populations of different species and determine whether they are in need of protection or not.

Unfortunately, while the IUCN does its best to save species that are teetering on the brink of extinction, it is not always possible. This was the case of the Western Black Rhino, which was just recently declared as officially extinct. Two of it's relatives, the black and white rhinos, are also critcally endangered, and it is thought that they could be gone within the next couple of years.

Rhinos are killed at a rate of about one a day in South African game parks. The WWF estimates around 340 have been slaughtered this year alone. One of the reasons that rhinos are so sought after is because of their horns. The horns can be sold as trophies or can be ground up and used as medicine. Chinese medicine takes these powdered horns and adds them to food or tea as an aphrodistiac.

Rhinos are not the only ones experiencing poaching for medicinal purposes. Tigers, bears, elks and sharks are also thought to have special properties, which has led to the killing of many members of these species as well. The IUCN has declared that around 25% of mammals are at risk of extinction. What these animals need are protection from hunters that can only be given if the demand for their products ceases. It is difficult, maybe impossible to change the beliefs of certain cultures, but it may be the only way to protect certain wild species on this planet.

Posted by Janelle Hayes

http://www.livescience.com/16971-iucn-mammals-rhino-extinct-biodiversity.html

http://www.livescience.com/17092-rhino-chinese-medicine.html

The Usefulness of Sea Cucumbers

A lot of humans’ problems have natural solutions. For example, the discovery of penicillin in fungi helped saved millions of lives. Scientists have found use of an organism that may be able to help clean up our oceans - the organism being a sea cucumber. These harmless creatures have a variety of uses, including being a nutritious delicacy in some cultures. Unfortunately, these creatures have been overharvested and sea cucumber populations in the wild are seriously depleted. Luckily, scientists found that sea cucumbers show a great deal of potential in their ability to clean up pollution on the ocean floor. Essentially, scientists plan to use sea cucumbers to clean up the waste created by fish farms.

Humans have left a huge eco-footprint on Earth the past few centuries and we are reaching our limit on how much more damage we can do to the environment. Thus, the discovery of the sea cucumber’s ability to convert the wastes created by fish farms to nutrients for its own survival is a great one. This is a win-win situation, where fish farms are going to be more sustainable with the use of these sea cucumbers and then sea cucumbers would also be saved from extinction. This discovery exemplifies the importance of preserving and studying organisms. We are discovering new species every day and by all of studying them, perhaps we will find solutions to other problems in the world.

Source: http://www.sciencedaily.com/releases/2011/02/110202202952.htm

Posted by James Lin (8)