''Andricus opertus'', the fimbriate gall wasp, is a species of wasp in the family

Cynipidae Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this genera ...

whose bisexual generation induces elongate, spiky

galls Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

on the leaves of various species of

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

s in

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, including

valley oak ''Quercus lobata'', commonly called the valley oak or roble, grows into the largest of California oaks. It is endemic to California, growing in interior valleys and foothills from Siskiyou County to San Diego County. Mature specimens may attain a ...

and

scrub oak Scrub oak is a common name for several species of small, shrubby oaks. It may refer to: *the Chaparral plant community in California, or to one of the following species. In California *California scrub oak (''Quercus berberidifolia''), a widespr ...

. The galls of the bisexual generation form in spring, adults emerge in late spring, and galls persist on trees until the fall. The unisexual generation of this species forms aborted bud galls in the summer and fall.

References

Cynipidae Gall-inducing insects Insects described in 1926 {{wasp-stub