Helina troene
This record describes Helina troene (species). Recorded family: Muscidae. Recorded order: Diptera.
Identification and Appearance
Females of troene and procedens may be difficult to separate. Snyder's (1949) key separates them by the number of AD bristles on the hind tibia (one in procedens, two in troene). I have seen specimens with a single AD on one leg and two AD on the other, so this may not be reliable. Snyder's descriptions say troene females have an unspotted abdomen, while procedens has spots, though weaker than the male. More study is needed. [Brad Barnd, 16.x.2025]
Classification
Habitat and Range
Geographic Range
Widespread. OR/WA to QC/ME, south to NC-IN-NV.
About Flies: the wider group
Order-level background for Diptera, the group containing Helina troene. 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 Helina troene (5)
Photo credits: Contributed by Brad Barnd
Frequently Asked Questions About Helina troene
What is Helina troene?
Helina troene is a species in the family Muscidae, within the order Diptera.
How do you identify Helina troene?
Females of troene and procedens may be difficult to separate. Snyder's (1949) key separates them by the number of AD bristles on the hind tibia (one in procedens, two in troene). I have seen specimens with a single AD on one leg and two AD on the other, so this may not be reliable. Snyder's descriptions say troene females have an unspotted abdomen, while procedens has spots, though weaker than the male. More study is needed. [Brad Barnd, 16.x.2025]
Where is Helina troene found?
Range: Widespread. OR/WA to QC/ME, south to NC-IN-NV.