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Eleodes - Calosoma simplex

Eleodes - Calosoma simplex
Peters Canyon Park, Orange County, California, USA
May 4, 2008
Size: ~3-5cm
Eleodes armatus?

Moved from Calosoma.

These Calasoma's have been ex
These Calasoma's have been extremely common this year in Orange County. I initially saw them along the coast, but today I observed large numbers of them either flying or running along the ground while hiking in the Santa Ana mountains. They are also in my backyard of my house in Trabuco Canyon. They are feeding on the Tussock moth caterpillars in my backyard.

Its a ground beetle (Carabidae), genus Calosoma

OK. What features tell you th
OK. What features tell you this is a ground beetle instead of a darkling beetle? and more specifically calosoma?

The Eleodes move much slower,
The Eleodes move much slower, do not fly, their abdomen is much harder, and they lack the large eyes and mandibles that the Calasoma have. Also, when touched, the Eleodes may walk faster or raise their abdomen and stop; Calasomas run faster and do not stop when touched.

I saw both beetles today while hiking and the Calasomas always appear to be in a mad rush to get somewhere, while Eleodes are more deliberate and slow. Also, Calasomas are predators and Eleodes primarily eat vegetation or dead matter. I hope that this helps.

Um, wrong family:-)
Actually, there 'might' be some mimicry involved...they both stink if you pester them:-) This is a ground beetle in the genus Calosoma.

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