Wednesday, April 20, 2011

Eleodes gigantea

Eleodes gigantea is a big black darkling beetle common throughout California in dry areas. It gets to be about an inch long and is really the epitome of the so-called "stink beetle". There are several species of Eleodes throughout the Western US and Mexico but E. gigantea is certainly one of the biggest. It is also one of the most - how should I describe it - expressive. Once it gets bothered, it sticks its rear end into the air, threatening to give off a foul odor, if anybody gets too close.

Last November, Michael decided he wanted to do a science fair project on these insects. He wanted to see if they had evolved their defense response as a protection more from aerial predators than from terrestrial ones. He made silhouettes of a predatory bird and another one the same size of a fox. Then Michael, Jon and I took a trip out past Coalinga (southwest of Fresno) to find the creatures. We spent 2 days driving around mountain roads and ended up finding several individuals that Michael exposed to the two silhouettes.

Michael thought that the beetles would go into defensive mode quicker when exposed to the fox. After all there are a lot of terestrial predators around - including a lot of non-native cats and dogs. But the beetles were much quicker to respond to the bird. It was a fun project and leaves open a lot of questions that somebody doing more than a high school science fair project might want to tackle.

In any event, the canyon was nice. Not too many insects were out (it was November) but the cool weather didn't seem to bother the beetles.

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