Two-horned Gall Wasp
Dryocosmus dubiosus
This record describes Dryocosmus dubiosus (species). Recorded family: Cynipidae. Recorded order: Hymenoptera.
Identification and Appearance
Classification
- Kingdom
- Animalia
- Phylum
- Arthropoda
- Class
- Insecta
- Order
- Hymenoptera (Ants, Bees, Wasps and Sawflies)
- Superfamily
- Cynipoidea
- Family
- Cynipidae (Gall Wasps)
- Tribe
- Cynipini
- Genus
- Dryocosmus
Imported taxonomy record. Source availability varies; see the source references and editorial policy below.
Diet and Behavior
Life History
Larvae of this wasp develop in galls on Quercus agrifolia (coast live oak) and Quercus wislizeni (interior live oak). The galls are easier to see and identify than the adult wasps. There are two generations per year, a bisexual generation and a unisexual generation. Galls from the bisexual generation are on catkins or along edges of new leaves. Galls from the unisexual generation occur on midrib and lateral veins on the underside of the leaves and have "horns" or points at each end.
About Flies: the wider group
Order-level background for Hymenoptera, the group containing Dryocosmus dubiosus. 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 Two-horned Gall Wasp (5)
Photo credits: Contributed by Joyce Gross; Additional contributions by ceiseman