Bug Spotlight!

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U.C. Riverside
Department of Entomology
Photo by: Rick Vetter 
"Carpenter Bees" Order Hymenoptera Family Apidae, genus Xylocopa

Prepared by Doug Yanega, photos Rick Vetter

These bees have a tendency to scare people because of their large size and the territorial behavior of the males (which do not sting), which will investigate virtually any moving object within their field of vision. In reality, about the only way to be stung by one is to grab a female in one's hand and squeeze, as they are totally non-aggressive. Females are solitary, each making her own private tunnel into dry wood, where she carves out one to several branches of the tunnel, dividing them into series of "cells" (small chambers set off by partitions made of wood fragments). Into each cell she places a mass of pollen mixed with nectar, upon which she lays a single large egg, which hatches into a larva after she seals the partition. The larvae feed for a few weeks, and then may or may not enter a resting prepupal stage (depending on the species, the climate, and the time of year) before pupating and emerging as an adult after about two weeks as a pupa. In California, the three common species are Xylocopa varipuncta (above), X tabaniformis, and X californica. The first species is most common in Southern California, and has all-black females with bluish wings (with metallic reflections; above, left), but the males are golden-brown (above, right); the second species has smaller black females, and the males are grayish with light faces; the last species resembles a bumblebee somewhat, though the females have darker yellowish hair on the thorax and the abdomen has definite blue or blue-green metallic tints to it. All carpenter bees can be easily differentiated from bumblebees by the relatively bare and shining dorsal surface of the abdomen, and the way they carry the pollen on the entire hind leg, instead of with the pollen concentrated in a single compact mass in a "pollen basket" as in bumblebees. Generally speaking, the damage they do is only cosmetic; it is very rare for them to remove enough wood to cause structural problems.


2006  ERM-UC Riverside