Insect · GBIF taxon 5090593
Prairie Lion Fly
Promachus fitchiiAlso known as Fitch's Robber Fly, Prairie Robber Fly
Prairie lion flies are formidable aerial predators of open grasslands, intercepting prey mid-air with extraordinary speed and precision. They perch on elevated grass stems or exposed twigs, scanning the skies for flying insects like bees, beetles, and grasshoppers before launching explosive ambush strikes. Once captured, prey is injected with neurotoxic saliva that quickly immobilizes it and liquefies its internal tissues for easy feeding.
PredatoryDiurnalGrassland
1 / 2—observations
—countries
—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Diet & prey
- Honeybees
- Grasshoppers
- Wasps
Predators
- Insectivorous birds
- Spiders
- Lizards
ThreatsHabitat loss, pesticide exposure, and grassland conversion
HabitatsPrairies, open grasslands, meadows, and agricultural field margins
Life span1–2 years
Size / weightNot available
Classification
- FamilyAsilidae
- SpeciesPromachus fitchii
Range data is not available yet.
Interaction riskLow
- Low
- Moderate
- High
- Very high
- Why interaction risk is low
- Can deliver a painful bite if caught or pinched; observe safely from a short distance.
- Why it is dangerous
- Delivers a painful bite using a stout, stabbing proboscis loaded with digestive enzymes.
- How to recognize a risky encounter
- Recognized by its large size, dense mustache of bristles, and prominent piercing beak.
- What to do
- Do not attempt to catch or hold by hand; view perched flies from a respectful distance.
Responsible observation
- Approach Slowly: Move calmly through sunny meadows to avoid startling perched individuals.
- Scan Stem Tips: Look at elevated grass heads and twigs where flies wait in ambush.
- Observe Without Touching: Avoid handling or trapping flies by hand to prevent defensive bites.
Grassland Competitor (c) Dan MacNeal, some rights reserved (CC BY), uploaded by Dan MacNeal · cc-by
Common Prey Andreas Trepte / CC BY-SA 2.5 · cc-by-sa
Genus Relative (c) Judy Gallagher, some rights reserved (CC BY-SA), uploaded by Judy Gallagher · cc-by-sa
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