Fauna
Insect · GBIF taxon 4294480

Black-shouldered Drone Fly

Eristalis dimidiata

Black-shouldered drone flies are convincing honey bee mimics that emerge as early as late March, making them vital early-season pollinators in northern forests. Adults spend sunny mornings warming themselves on tree bark or hovering motionlessly before darting toward blossoming spring ephemerals. Their larvae, known as rat-tailed maggots, develop in stagnant, nutrient-rich water where a long breathing tube allows them to feed on decomposing organic debris.

PollinatorDiurnalMimic
Black-shouldered Drone Fly reference1 / 7
Licensed reference(c) Gilles Gonthier, some rights reserved (CC BY) · cc-by
—observations
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Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & prey
  • Flower nectar
  • Pollen
Predators
  • Songbirds
  • Crab spiders
  • Dragonflies
ThreatsBroad-spectrum pesticide application, wetland drainage, and loss of early-blooming native forest flora
HabitatsDeciduous and mixed forests, woodland edges, wetlands, and wet meadows
Life spanSeveral months (overwinters as an adult)
Classification
  1. FamilySyrphidae
  2. SpeciesEristalis dimidiata
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Harmless bee mimic without a sting; safe to observe closely.
Responsible observation
  • Spotting Eyes: Look closely at the head; males have large eyes that touch at the top, while females have separated eyes.
  • Wing Count: Check the wings to confirm identity; true flies possess only one pair of wings, while bees have two.
  • Early Season Searching: Scan sunny patches of tree trunks and early woodland blooms in late March and April.
Related species
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