Rain-beetles
Guides
Pleocoma
rain beetles
Pleocoma is the sole extant genus of Pleocomidae, a family endemic to the Pacific states of North America. These beetles are notable for their extreme subterranean lifestyle, with adults emerging only during fall and winter rains to mate. The genus name derives from Greek words for 'abundant hair,' referring to the dense ventral hair covering. Adults are non-feeding, while larvae are root-feeders with exceptionally long development periods of up to 13 years.
Scarabaeoidearain-beetlessubterraneannon-feeding-adultslong-lived-larvaepheromone-mediated-matingendemicNearcticrelictual-distributionCretaceous-originpest-of-Christmas-treeslamellate-antennaeflightless-femalesrain-triggered-emergenceCalifornia-faunaOregon-faunaWashington-faunaroot-feeding-larvaeextreme-seasonalitylight-attracted-malesPleocomidae
Rain Beetles
Pleocomidae, known as rain beetles, is a family of scarabaeoid beetles found in western North America. The family contains a single extant genus, Pleocoma, with two extinct genera known from the fossil record. Adults emerge in response to rain or snow events, giving the group its common name. The family is considered the sister group to all remaining families of Scarabaeoidea. At least one species, Pleocoma dubitabilis dubitabilis, has been documented as a pest of Christmas trees.