Brown-headed Ash Sawfly
Tomostethus multicinctus
This record describes Tomostethus multicinctus (species). Recorded family: Tenthredinidae. Recorded order: Hymenoptera.
Identification and Appearance
sporadic but important early-season defoliator in e. US & CO
Classification
- Kingdom
- Animalia
- Phylum
- Arthropoda
- Class
- Insecta
- Order
- Hymenoptera (Ants, Bees, Wasps and Sawflies)
- Family
- Tenthredinidae (Common Sawflies)
- Subfamily
- Blennocampinae
- Tribe
- Tomostethini
- Genus
- Tomostethus
Imported taxonomy record. Source availability varies; see the source references and editorial policy below.
Habitat and Range
Geographic Range
e. NA (MA-NC to ND-TX) + OR-CA
Diet and Behavior
Diet: hosts: Fraxinus ; green ash particularly susceptible
Life History
Overwinters as full grown larva inside a cocoon near the base of infested ash trees. Pupation occurs in early spring and adult wasps swarm ash trees. Eggs are laid in slits cut along the outer margin of young leaflets, several eggs per leaflet. Full-grown larvae move to and enter the ground by late May in the south, later dates in the north. Pupation occurs in the spring. ( 3 ) One generation per year. ( 3 )
Additional species information
Species notes from the sources
Etymology: Tomostethus multicinctus (Rohwer 1909)
About Flies: the wider group
Order-level background for Hymenoptera, the group containing Tomostethus multicinctus. 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 Brown-headed Ash Sawfly (4)
Photo credits: Contributed by Ken Schneider; Additional contributions by Beatriz Moisset , John S. Ascher , v belov , Marci Hess
Frequently Asked Questions About Brown-headed Ash Sawfly
What is Brown-headed Ash Sawfly?
Brown-headed Ash Sawfly (Tomostethus multicinctus) is a species in the family Tenthredinidae, within the order Hymenoptera.
Where is Brown-headed Ash Sawfly found?
Range: e. NA (MA-NC to ND-TX) + OR-CA
What does Brown-headed Ash Sawfly eat?
The diet of the Brown-headed Ash Sawfly includes hosts: Fraxinus ; green ash particularly susceptible.
What is the life cycle of a Brown-headed Ash Sawfly?
Overwinters as full grown larva inside a cocoon near the base of infested ash trees. Pupation occurs in early spring and adult wasps swarm ash trees. Eggs are laid in slits cut along the outer margin of young leaflets, several eggs per leaflet. Full-grown larvae move to and enter the ground by late May in the south, later dates in the north. Pupation occurs in the spring. ( 3 ) One generation per year. ( 3 )