Friday, November 16, 2007

Parasites Linked to Odd Breeding Habits in Amphibians

Most people know that frogs lay their eggs in streams and ponds, where they then hatch as tadpoles and develop into the adult form over time. There are many benefits to this type of breeding behavior but the main reason is the large food supply. There is also some disadvantages, one being risk of exposure to parasites. When many amphibians are forced to breed in the same place, the likelihood that they will be exposed to parasites is raised dramatically. One researcher from the University of Georgia believes that these parasites have sparked some very odd evolutionary paths relating to the breeding patterns of certain amphibians.

Brian Todd, the Ecologist behind the idea, notes that there are many strange amphibian breeding habits to be found in nature:
"Take, for instance, the Darwin’s frog, the species that swallows its eggs and, a few weeks later, regurgitates its young. Or the marsupial frog, a species that carries its eggs on its back until they hatch. Several species lay eggs in small puddles on land or high up in trees where they hatch as miniature versions of adults, bypassing the larval stage entirely."
He suggests that such habits could be adaptations that have been naturally selected for due to the threat of parasites in lakes and ponds. With enough parasites present, the cost of being inside the pond outweighs the benefits.

Todd hopes that his hypothesis will be tested in the future and even offered a few ideas to help speed up the process. He believes that parasites have been overlooked by most scientists when it comes to their effect on evolution and hopes that people will begin to realize the effects they can have. Amphibians, he predicts, will play a key role in this realization.

Source: Science News

Posted by Ben Tummino (8)


At 6:06 PM, Blogger PWH said...

That's an interesting article. I've never heard anyone suggest parasites as a way for changing breeding behavior. Did the article say any other examples of species that possibly change breeding behavior because of parasites? It seems to make sense and is a good explanation for the amphibians.

Posted by: Christine McConville

At 7:59 PM, Blogger PWH said...

This was really iteresting. I liked the examples that they gave, especially the one that carries its eggs in its mouth, thats crazy. It will be interesting to see if further research shows more species who's evolution is affected by parasites like this.

Posted by Hollis Martin

At 11:15 PM, Blogger PWH said...

Wow, this is a very interesting article. I have never heard of such odd patterns within frogs. Do you know how different these frogs are, or at anytime did these frogs go back to their "normal" development patten or do these frogs always develop with these different pattern.

posted by:
Balkrishna Gantyala (8)


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