Callirhytis serricornis

The bottle- or vase-shaped gall morphology distinguishes this species from other California oak gall wasps. First-generation brown galls and second-generation red-green galls on coast live oak or interior live oak are diagnostic. Differentiation from congeneric Callirhytis species requires examination of gall shape, host association, and generation-specific coloration.

Adult wasps are small, typical cynipids with reduced wing venation. The specific epithet 'serricornis' refers to serrated antennae. Galls induced by this species are distinctive: bottle- or vase-shaped structures attached to oak tissues. First-generation galls are brown in coloration; second-generation galls display red and green coloration.

Restricted to oak woodlands and savannas in California where host oaks (Quercus agrifolia and Quercus wislizeni) occur. Galls develop on above-ground tissues of host trees.

Endemic to California, western United States. Range corresponds to distribution of coast live oak (coastal California) and interior live oak (foothills and interior valleys).

Activity patterns follow the alternating sexual and agamic generations typical of cynipids with heterogony. Specific seasonal timing not documented in available sources.

Larvae feed on nutritive tissue within induced galls on oak hosts. Adults do not feed; larvae are the only feeding stage.

• Quercus agrifolia - hostcoast live oak; oviposition site and gall development
• Quercus wislizeni - hostinterior live oak; oviposition site and gall development

Exhibits heterogonic life cycle with alternating sexual and parthenogenetic (agamic) generations. Two distinct gall morphs correspond to generations: brown galls (first generation) and red-green galls (second generation). Larval development occurs within galls.

Females oviposit into oak tissues, inducing gall formation. The wasp manipulates host plant development to create a protective structure and food source for larvae.

Induces structural galls on oak trees, creating microhabitats that may be used by other organisms. Acts as a specialist herbivore with narrow host range.

No documented economic or medical significance. Of interest to students of gall wasp biology and California oak ecology.

• Callirhytis quercuspunctataAlso induces galls on California oaks; differentiated by gall morphology (gouty oak gall vs. bottle/vase shape) and specific host associations
• Callirhytis clavulaCongeneric oak gall wasp with different gall structure; produces harder, less succulent galls without latex exudate

• gall wasp
• Cynipidae
• California endemic
• oak gall
• heterogony
• Quercus agrifolia
• Quercus wislizeni

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• ID Challenge #3 | Beetles In The Bush