Therion circumflexum
This record describes Therion circumflexum (species). Recorded family: Ichneumonidae. Recorded order: Hymenoptera.
Identification and Appearance
Very large size. Coloration: head black (female with only orbits and central stripe yellow, male with face entirely yellow), thorax black with at most some red spots, wings light brown, coxae black, trochanters red, first 3 abdominal segments strongly red. Anterior of T1 black as opposed to entirely amber as in T. fuscipenne . Hind tibia longer than combined length of hind femur plus trochanters. ♀ ♂
Wikipedia reference for Therion circumflexum: https://en.wikipedia.org/wiki/Therion_circumflexum.
Classification
- Kingdom
- Animalia
- Phylum
- Arthropoda
- Class
- Insecta
- Order
- Hymenoptera (Ants, Bees, Wasps and Sawflies)
- Superfamily
- Ichneumonoidea
- Family
- Ichneumonidae (Ichneumonid Wasps)
- Subfamily
- Anomaloninae
- Tribe
- Gravenhorstiini
- Genus
- Therion
Imported taxonomy record. Source availability varies; see the source references and editorial policy below.
Habitat and Range
Habitat
oak-chaparral, willows ( 5 )
Geographic Range
widespread in some parts of the Palearctic & Nearctic realms ( 3 ) ( 4 )
Seasonal Activity
Adults fly from mid-June to September in Commanster, Luxembourg. ( 6 )
Diet and Behavior
Life History
Adult females search out caterpillar hosts using both tactile and olfactory cues. She uses her antennae to feel the surface to determine that the integument is wrinkled with no patches of setae present, which indicate an appropriate host. A female will only oviposit in hosts that meet these requirements and will reject any other species, even in the prolonged absence of hosts with the proper tactile cues. ( 5 )
Additional species information
Species notes from the sources
Etymology: Therion circumflexum (Linnaeus, 1758)
About Flies: the wider group
Order-level background for Hymenoptera, the group containing Therion circumflexum. 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 Therion circumflexum (3)
Photo credits: Contributed by Bob Biagi; Additional contributions by PaleoJon
Frequently Asked Questions About Therion circumflexum
What is Therion circumflexum?
Therion circumflexum is a species in the family Ichneumonidae, within the order Hymenoptera.
How big is Therion circumflexum?
Body length of over 20 mm, one of our largest species
How do you identify Therion circumflexum?
Very large size. Coloration: head black (female with only orbits and central stripe yellow, male with face entirely yellow), thorax black with at most some red spots, wings light brown, coxae black, trochanters red, first 3 abdominal segments strongly red. Anterior of T1 black as opposed to entirely amber as in T. fuscipenne . Hind tibia longer than combined length of hind femur plus trochanters. ♀ ♂
Where is Therion circumflexum found?
| Feature | Details |
|---|---|
| Habitat | oak-chaparral, willows ( 5 ) |
| Range | widespread in some parts of the Palearctic & Nearctic realms ( 3 ) ( 4 ) |
When is Therion circumflexum active?
Therion circumflexum: seasonal activity - Adults fly from mid-June to September in Commanster, Luxembourg. ( 6 ).
What is the life cycle of a Therion circumflexum?
Adult females search out caterpillar hosts using both tactile and olfactory cues. She uses her antennae to feel the surface to determine that the integument is wrinkled with no patches of setae present, which indicate an appropriate host. A female will only oviposit in hosts that meet these requirements and will reject any other species, even in the prolonged absence of hosts with the proper tactile cues. ( 5 )