Amphibians' Outlook Just Got Worse - Fungus May Now Be Endemic, Reproducing Sexually, Lasts 10 Years

[hatrack]

The deadly fungal disease that is killing amphibians worldwide can likely be spread by sexual reproduction reports a new study published in the early online edition of the journal Proceedings of the National Academy of Sciences. The findings suggest that protecting frogs and other amphibians from the pathogen will be more complicated than previously believed.

Analyzing the DNA of the Batrachochytrium dendrobatidis among mountain yellow-legged frogs in the California Sierra Nevadas, researchers led by Jess Morgan found that when the fungus reproduces sexually, it creates spores that can last more than a decade.

"That could make this pathogen a harder problem to defeat. As a resistant spore, the fungus could be transported by animals, including humans or birds, or lay dormant in an infected area until a new host comes along," said John Taylor, a University of California at Berkeley professor of plant and microbial biology who was the principal investigator of the study.

To better understand how the fungus spreads and reproduces, the researchers sought to determine which of two competing hypotheses on the origin of the disease. "If the fungus was recently introduced to an area, the researchers would expect to find a single genotype that had spread by clonal reproduction. If, however, the fungus is endemic to a region, they would expect to find diverse genotypes resulting from a long history of association that provides enough time for isolates to diverge through mutation and genetic recombination," explained a statement from UC Berkeley. "If the fungus is endemic to a region, the animals in the area would normally be resistant to its destructive effects because they would have co-evolved together. However, biologists theorize that changes to the environment - from global warming to pollution from agricultural chemicals - could make native frog populations susceptible to a pathogen with which they've previously co-existed."

EDIT

http://news.mongabay.com/2007/0806-frogs.html

[kestrel91316]

1. I watched a Snowy Egret catch and eat a frog this weekend at

a local pond. What will the egrets eat when the frogs are gone?

The answer, of course, is that their numbers will decline and they will eat more fish. And the fishes numbers will decline. Etc.