Europe PMC · 2026-06-12
A South African orchid called Satyrium longicolle is exclusively pollinated by long-tongued horseflies, and this specialized relationship keeps it reproductively isolated from neighboring orchid species pollinated by moths — even though the plants grow side by side and bloom at the same time.
Satyrium longicolle is pollinated exclusively by long-proboscid Philoliche horseflies during the day, which ignored strongly scented moth-pollinated orchids growing in the same habitat.
The orchid's cream-colored flowers reflect UV light, distinguishing them from white UV-absorbing hawkmoth-pollinated flowers — a difference visible to insect eyes but not human ones.
Spur length of S. longicolle co-varies geographically with local horsefly proboscis length, and while crosses with a moth-pollinated congener can produce seeds with embryos, pollinator behavior alone maintains near-complete reproductive isolation.
