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Fire-colored Beetles

Fire-colored Beetle Larvae

11-19-18 fire-colored beetle _U1A1193 (1)

Peek under the loose bark of rotting logs, both deciduous and coniferous, and you’re bound to find the larva of a beetle known as a Fire-colored Beetle (family Pyrochroidae).  Its common name is derived from the Greek word pyros (“fire”) + chroma (“’color”), a reference to the bright color, often red, of the adults of some species.   From one to several years are spent in the larval stage. Adults of the Pyrochroinae emerge from late spring to midsummer and are primarily nocturnal.

Many adult Fire-colored Beetles are attracted to cantharidin, a toxic compound produced by Blister Beetles.  Males locate a Blister Beetle, climb onto it and lick off the cantharidin that Blister Beetles exude and use the blistering agent to impress a female of their own species. When mating takes place, most of the cantharidin is transferred to the female in the form of a sperm packet.  The eggs the female subsequently lays are coated with cantharidin to protect them from being eaten before they hatch. (

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