Atrusca quercuscentricola

The galls of Atrusca quercuscentricola can be distinguished from other oak galls by their occurrence specifically on post oak (Quercus stellata), their colorful appearance, and the presence of a characteristic adult emergence hole. The galls are leaf galls rather than twig galls, which separates them from species such as Disholcaspis quercusglobulus. The specific epithet 'quercuscentricola' references its association with oak (Quercus) and its centric (central) position on the leaf.

The adult wasp is a small, inconspicuous hymenopteran typical of gall wasps. The galls it produces on post oak leaves are the most visible manifestation of this species—colorful, rounded structures with a distinct adult emergence hole visible upon maturation. The galls are attached to the leaf surface and may show vibrant color patterns that distinguish them from other oak galls.

Occurs in dry post oak woodlands and glade margins where the host plant Quercus stellata is present. The wasp has been documented in Missouri at Valley View Glades Natural Area and similar habitats with post oak-dominated vegetation.

Documented from Missouri, with specific records from Jefferson County (Valley View Glades Natural Area). The distribution is likely broader across the range of post oak in the central United States, though precise records are sparse.

Adult emergence and gall formation occur during the growing season. Based on observations, galls with fresh emergence holes have been noted in fall (October), suggesting late-season adult activity. The species likely has a univoltine life cycle with overwintering occurring within the gall or as pupae.

• Quercus stellata - host plantPost oak; the wasp induces galls on the leaves of this species

The female wasp lays eggs in the leaf tissue of post oak using her ovipositor. The larvae hatch and secrete plant growth-like hormones that induce the formation of a gall. The larva develops inside the gall, feeding on the specialized plant tissue. Upon maturation, the larva pupates within the gall, and the adult emerges by chewing an exit hole through the gall wall. The emerged adults likely reproduce immediately, with females laying eggs in new leaf tissue to begin the next generation.

Adult females use their ovipositor like a hypodermic needle to inject eggs into leaf tissues. The wasp is incapable of stinging humans. The species is parthenogenetic or has an alternating sexual/asexual generation cycle typical of many cynipids, though this has not been explicitly documented for this species.

As a gall-former, this species manipulates host plant growth to create a protected microhabitat for its offspring. The galls may provide food and shelter for other organisms, including inquilines and parasitoids. The wasp contributes to the complex community of gall-forming insects associated with oak ecosystems.

Primarily of interest to entomologists and naturalists studying gall wasp diversity and oak-associated insect communities. The colorful galls are visually striking and may attract attention from hikers and nature observers. No economic or medical significance is known.

• Andricus pattoniAnother cynipid gall wasp that forms galls on post oak (Quercus stellata), but produces galls on the abaxial leaf surface rather than the more centrally positioned galls of A. quercuscentricola
• Andricus dimorphusForms clustered midrib galls on chinquapin oak (Quercus muhlenbergii), a different host species and gall morphology
• Disholcaspis quercusglobulusForms round bullet galls on twigs of white oak (Quercus alba), not leaf galls on post oak

• gall wasp
• cynipid
• oak gall
• leaf gall
• Quercus stellata
• post oak

• BugGuide
• iNaturalist taxon
• NCBI Taxonomy
• Cynipidae | Beetles In The Bush
• nature | Beetles In The Bush | Page 9
• Insecta | Beetles In The Bush | Page 8
• glades | Beetles In The Bush
• landscapes | Beetles In The Bush | Page 5
• entomology | Beetles In The Bush | Page 7