Hedgehog Gall Wasp
Acraspis erinacei
This record describes Acraspis erinacei (species). Recorded family: Cynipidae. Recorded order: Hymenoptera.
Identification and Appearance
Forms galls on white oak ( Quercus alba ). The sexual generation forms galls on the buds, and the agamic generation forms the distinctive hedgehog galls (ellipsoid, up to 13 mm in diameter, covered with red hairs, with 3-5 larval cells inside) on leaves. Females emerge from the leaf galls in the fall (October-December) and crawl to the buds to oviposit. The resulting gall is a thin-walled blister on the inner face of a bud scale, appearing as the buds start to open in the spring. There is a bi-sexual form, A. bicolens , that forms seed-like, egg-shaped galls in buds on Quercus alba with adults emerging in May.
Classification
- Kingdom
- Animalia
- Phylum
- Arthropoda
- Class
- Insecta
- Order
- Hymenoptera (Ants, Bees, Wasps and Sawflies)
- Superfamily
- Cynipoidea
- Family
- Cynipidae (Gall Wasps)
- Tribe
- Cynipini
- Genus
- Acraspis
Imported taxonomy record. Source availability varies; see the source references and editorial policy below.
About Flies: the wider group
Order-level background for Hymenoptera, the group containing Acraspis erinacei. Species-specific details appear above.
Group overview
Hymenoptera includes over 150,000 described species of ants, bees, wasps, and sawflies. Earth harbors approximately 20 quadrillion (20×10^15) ants, with a combined biomass of ~12 megatons of dry carbon - exceeding the combined biomass of all wild birds and mammals (PNAS, 2022).
Ecological role of the group
About 35% of the world's food crops depend on animal pollinators. The chocolate industry, valued at over $100 billion, depends on pollinating flies and midges. Ants are the dominant soil engineers in most terrestrial ecosystems, turning more soil than earthworms in many habitats.
Economic and practical significance of the group
Pollinators contribute $235-577 billion worth of annual global food production (FAO). In the U.S., bee pollination alone benefits crops valued at $18 billion annually, and honey bees are responsible for $5.4 billion in agricultural productivity. Between April 2023-2024, 55.1% of managed honey bee colonies were lost. The U.S. bee population dropped from 5 million to 2.5 million.
Recorded sources for this group: FAO, USDA, EPA, PNAS (2022), US Fish & Wildlife Service. Imported estimates may describe particular regions or reporting periods.
Photos of Hedgehog Gall Wasp (5)
Photo credits: Contributed by Charley Eiseman; Additional contributions by john and jane balaban , Marci Hess