Achaius oratorius

This record describes Achaius oratorius (species). Recorded family: Ichneumonidae. Recorded order: Hymenoptera.

Identification and Appearance

This is a medium-sized species (11–15mm) and has a black body with white spots. The precise pattern of white around the inner margin of the eyes, the white bands on each pair of legs together with the white band on the first abdominal segment are distinctive. The second, larger pale band on the abdomen is often absent. Can be confused with other black Ichneumoninae with white spots. The larvae feed on butterfly and moth larvae. Thought to be a fairly common species in Britain but little recorded.

Classification

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Ichneumonidae
Genus: Achaius

Imported taxonomy record. Source availability varies; see the source references and editorial policy below.

Habitat and Range

Habitat

Hedgerows and copses.

Seasonal Activity

June to September

Diet and Behavior

Life History

The larvae feed on butterfly and moth larvae.

Additional species information

Recorded status

Thought to be a fairly common species in Britain but little recorded.

About Flies: the wider group

Order-level background for Hymenoptera, the group containing Achaius oratorius. 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.

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