Violet Black-legged Robber Fly
Dioctria atricapilla
This record describes Dioctria atricapilla (species). Recorded family: Asilidae. Recorded order: Diptera.
Identification and Appearance
Length: 10-12mm. This is an all blue-black robberfly with bright yellow halteres. It is the only Doctria species with all black legs. Males have prussian blue eyes. The wings are darkened towards the base, particularly in the male. The female has a golden face whereas in the male it is dark brown. Unless identified by a recognised expert, a photo is required. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed. Around grassland where it usually rests on grass stems and sometimes in woodland rides. Predatory on small insects, particularly other flies and parasitic hymenopterans. Widespread in the southern half of Britain.
Classification
Habitat and Range
Habitat
Around grassland where it usually rests on grass stems and sometimes in woodland rides.
Seasonal Activity
May to July.
Diet and Behavior
Life History
Predatory on small insects, particularly other flies and parasitic hymenopterans.
Additional species information
Recorded status
Widespread in the southern half of Britain.
About Flies: the wider group
Order-level background for Diptera, the group containing Dioctria atricapilla. Species-specific details appear above.
Group overview
Diptera includes over 150,000 described species of flies, mosquitoes, and midges. Mosquitoes are the deadliest animal on Earth (CDC). Malaria alone causes ~249 million cases and over 608,000 deaths annually, mostly children under 5 (WHO). Vector-borne diseases account for over 17% of all infectious diseases, causing 700,000+ deaths per year.
Ecological role of the group
Despite their disease impact, flies are critical decomposers and pollinators. Hoverflies alone pollinate hundreds of crop and wildflower species. Flies are also the primary food source for many birds, bats, and fish. Forensic entomology relies heavily on fly species for crime scene analysis.
Economic and practical significance of the group
In the U.S., vector-borne disease cases tripled between 2004-2016, with over 640,000 cases reported in that period (CDC). Tickborne diseases doubled from 22,000 to 48,000 annual reports. Globally, mosquito-borne diseases cost billions in healthcare and lost productivity.
Recorded sources for this group: WHO, CDC, PNAS. Imported estimates may describe particular regions or reporting periods.
Photos of Violet Black-legged Robber Fly (10)
Frequently Asked Questions About Violet Black-legged Robber Fly
What is Violet Black-legged Robber Fly?
Violet Black-legged Robber Fly (Dioctria atricapilla) is a species in the family Asilidae, within the order Diptera.
How big is Violet Black-legged Robber Fly?
10-12mm. This is an all blue-black robberfly with bright yellow halteres. It is the only
Where is Violet Black-legged Robber Fly found?
Habitat: Around grassland where it usually rests on grass stems and sometimes in woodland rides.
When is Violet Black-legged Robber Fly active?
Violet Black-legged Robber Fly: seasonal activity - May to July..
What is the life cycle of a Violet Black-legged Robber Fly?
Predatory on small insects, particularly other flies and parasitic hymenopterans.