Batesian mimicry – where harmless species (mimics) imitate dangerous ones (models) – is widespread in nature. Yet hoverflies exhibit puzzling diversity: some perfectly replicate wasp patterns, while others show only vague yellow-black stripes or mismatched body shapes. If precise mimicry maximizes survival, why do imperfect versions persist?
The team designed 4 insect model types:
1️⃣ True wasp: Toxic model (Vespula vulgaris)
2️⃣ Perfect hoverfly mimic: Volucella zonaria (95% visual match)
3️⃣ Imperfect mimic: Syrphus ribesii (60% similarity)
4️⃣ Non-mimic: Housefly (Musca domestica)
These were deployed across UK woodlands with motion-activated cameras recording predator interactions over 6 months.
| Predator Type | Behavior | Survival Impact |
|---|---|---|
| Birds (Tits, Robins) | Avoided true wasps (0 attacks), attacked 73% of imperfect mimics | Strong selective pressure for precision |
| Invertebrates (Crab spiders, Mantis) | Avoided ALL striped models (attack rate: wasp 8%, perfect mimic 11%, imperfect mimic 13%) | Crude mimicry suffices |
"A crab spider won't risk eating anything that even whispers 'wasp'." – Dr. Henry Palmer, lead author
The 30% Rule: Imperfect mimics survive if ≥30% of local predators (e.g., invertebrates) are gullible
Mimicry Saturation: High density of mimics increases predator caution – imperfect mimics benefit from "collective protection"
Failed Strategy: Multi-model mimics (e.g., wasp+bee patterns) showed no survival advantage over single-model imitators
"Perfection is optional; adequacy is evolutionary gold," states co-author Dr. Chen Li. This explains why:
Hoverfly larvae develop mimicry in 3 days (energy-cheap) vs 14 days for precision patterns
68% of known mimics are "low-fidelity" – saving resources for reproduction
Robotics: Developing low-cost threat-displaying drones for crop protection
Conservation: Using imperfect decoys to deter poachers from endangered species