Zapatella quercusmedullae
(Ashmead)
Oak Rough Bulletgall Wasp
Zapatella quercusmedullae is a gall wasp in the Cynipidae that induces galls on oak trees (Quercus). The was transferred from Andricus to Zapatella based on phylogenetic studies. It produces distinctive bullet-shaped galls on twigs and branches of oaks. The has an alternating sexual and typical of many Cynipini.
Pronunciation
How to pronounce Zapatella quercusmedullae: /zəpəˈtɛlə kwɜrkəsˈmɛdʊlaɪ/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Galls are woody, bullet-shaped, approximately 5–10 mm in diameter, with a rough, pitted surface. They are attached directly to twigs and small branches, not to leaves or petioles. Galls are single-chambered and contain one larva. Distinguished from other bullet galls on oaks by the rough texture and twig placement; Andricus confertus produces similar but smoother galls.
Habitat
Deciduous oak forests and woodlands; associated with Quercus in temperate eastern North America.
Distribution
Eastern North America, from the northeastern United States through the Midwest and into the southeastern states. Records concentrated in the oak-hickory forest region.
Seasonality
Galls are present year-round on twigs. emerge in spring (sexual ) and late summer to fall ( generation).
Diet
Larvae feed on nutritive tissue within the gall induced on oak tissue. do not feed; sexual adults may ingest plant fluids.
Host Associations
- Quercus - induces galls on twigs and branches
- Quercus rubra - confirmed
- Quercus alba - confirmed
Life Cycle
Alternating : females produce galls that overwinter and yield sexual males and females in spring. Sexual generation produces a second gall type on leaves or buds that yields asexual females. The twig galls described here represent the asexual generation.
Ecological Role
Gall formation creates microhabitats for and . The contributes to oak-associated diversity. Galls may cause minor twig dieback but do not significantly harm healthy trees.
Human Relevance
Occasional curiosity for naturalists studying plant-animal interactions. No economic importance; not a pest of commercial oak plantings.
Similar Taxa
- Andricus confertusProduces smooth bullet galls on oak twigs; distinguished by gall surface texture and microscopic examination of
- Zapatella quercusclavulaSimilar bullet gall ; distinguished by oak preference and gall size
- Zapatella quercuspyriformisProduces pear-shaped rather than bullet-shaped galls on oaks