Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-9-07. © Ron Hemberger

Wedge-shaped Beetle

Rhipiphorus rex

Coleoptera: Rhipiphoridae

These beetles are phoretic parasitoids, like certain meloid beetles.  Females lay eggs into flowers and the hatchlings, called triungulins, then hitch a ride with visiting solitary bees.  Carried to the bees' nest, they become internal parasites of the host larvae. Eggs are laid - here on composite - on buds that will soon bloom. Apparently, the idea is to have the young ready to fly off to their new "families" as soon as the flower is ready for the bees' visits.

The elytra (forewings) are reduced to nubs, exposing the hindwings in these unusual beetles

Text by Hartmut Wisch and Ron Hemberger


Elytrae reduced to scales, leaving membranous hindwings exposed. Thought to ba a bee mimic. Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-9-07. © Ron Hemberger

Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-9-07. © Ron Hemberger

Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-9-07. © Ron Hemberger

Laying eggs on flower. Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-9-07. © Ron Hemberger

Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-16-07. © Ron Hemberger

Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-16-07. © Ron Hemberger

Thomas E. Riley Wilderness Park, Coto de Caza, Orange County, CA. 6-16-07. © Ron Hemberger