Callirhytis favosa

Distinguished from other Callirhytis species by the honeycomb-patterned galls on oak leaves. The galls differ from the bullet galls of C. quercuspunctata, the woolly galls of C. seminator, and the horned twig galls of C. cornigera. The sexual generation galls on leaves are structurally distinct from the asexual generation galls produced by the same species.

Associated with oak trees (Quercus species), particularly white oaks. The species requires oak woodland or forest environments where host trees are present.

Eastern North America. Documented observations span from the northeastern United States through the Midwest, with records from Missouri and surrounding regions.

Activity follows the phenology of oak trees. Sexual generation adults emerge in spring shortly after oak bud burst. Asexual generation development occurs through summer and fall, with emergence timing varying by generation.

Larvae feed on nutritive plant cells induced within the gall tissue. Adults have been observed feeding on sweet secretions produced by cynipid galls.

• Quercus - gall hostSpecific oak species not confirmed; likely white oak group based on genus-level patterns in Callirhytis

Alternating generations with different gall forms: sexual generation produces leaf galls, asexual generation produces distinct galls elsewhere on the plant. Development from egg to adult occurs within the gall. Larvae transform to pupae within a protective larval chamber inside the gall, emerging as adults by chewing exit holes.

Females induce gall formation through egg-laying and subsequent chemical secretions that alter plant development. Larval movement within galls has been observed in related species but not specifically documented for C. favosa.

Gall formation creates microhabitats that support arthropod communities. Galls produce secretions that attract predatory wasps and other insects. Serves as host for parasitoid wasps and inquilines that inhabit cynipid galls.

• Callirhytis quercuspunctataProduces bullet galls on oak twigs rather than honeycomb leaf galls; galls are hard, woody, and spherical with distinct exit holes
• Callirhytis seminatorProduces woolly or spongy galls; gall texture and structure differ markedly from honeycomb pattern
• Callirhytis cornigeraProduces horned oak galls on twigs with distinctive woody horns; gall location and morphology differ
• Antistrophus speciesGall wasps in different genus that form stem galls on Silphium rather than leaf galls on oak

• cynipidae
• gall wasp
• oak gall
• hymenoptera
• leaf gall
• alternating generations
• parthenogenesis

• BugGuide
• iNaturalist taxon
• ID Challenge #3 | Beetles In The Bush
• What’s that on an oak leaf? Animal? Plant? Fungus? Nah, gall insect – Galls wasps, Cynipidae — Bug of the Week