Sunday, October 03, 2004

Dermestid Beetles 1, Army Ants 0

My dad just e-mailed me about a very neat article of Ant vs. Beetle, and since his summary of it is better than anything I could write, here it is:

"The SF Chronicle had an article today about the loss of part of an exhibit of ants at the Academy of Sciences. They had a 500 square-foot case housing a colony of Eciton burchellii, otherwise known as 'army ants'. They accidentally introduced some hide beetles, Dermestes maculata, into the case. more ants. The fast reproducing beetles wiped out some 1.2 million army ants!

"The beetles were introduced as larvae or pupae hiding among the lots of live crickets purchased as food for the ants. The larvae hatched into adult beetles, which multiplied as follows; a typical female beetle lays about 400 eggs during a 100 day lifespan. Eggs hatch in three days, are adults within a month and are ready to mate and lay eggs five days later. The beetles ate the ants' food, as well as the ants themselves, it seems. And why couldn't the army ants, the scourge of the tropics, simply eat the beetles? The beetle larvae have long hairs on them which prevented the ants from biting them. Besides, they contain chemicals making them indigestible. So in a few months, the beetles had wiped out the ant colony completely. The curators couldn't even find the queen.

"So here we have a native species defeating an exotic. Or do we? How did the beetle vs ant situation become a zero-sum game? Probably because in the artificial ecology of the display case, there were no factors acting to reduce the beetle population. At least none capable of controlling the beetles sufficiently to keep them from overwhelming the ants.

"It doesn't help that Dermestes is the little beetle that museums use to clean bones. According to the article, they eat almost anything organic including leather, feathers, and horn."

Thanks dad!

No comments: