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Inflated Beetle

Cysteodemus armatus

Inflated Spider Beetle, Cysteodemus armatus, photo by Michael Plagens

Photo taken April 30, 2010 at Joshua Tree National Monument, California, USA..

The odd appearance of these spring-time beetles is sure to attract the attention of desert observers in the American Southwest. They bumble along seemingly encumbered by an over-sized, highly inflated abdomen. They might be seen crawling on the soil or up into plants to nip at flower petals or tender leaves.

Their peculiar appearance is only exceeded by the oddness of their life style. A bird or lizard might find Inflated Beetles an easy catch only to be poisoned by toxic chemicals smeared on their shell (yellow or white material) and leaking from a broken body. Somehow, even na´ve insectivores know not to eat these beetles.

The eggs of this beetle hatch into minute, mobile critters called triungulin that eventually find their way into the underground chambers of soil-nesting bees. There they latch onto developing bee grubs as ectoparasites.

Meloidae -- Blister Beetle Family

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Copyright Michael J. Plagens, 1999-2011