Do Mimic Hoverflies Spatially Match Their Bumblebee Models? Evidence From a Polymorphic Mimicry System

Area of Science:

• Ecology
• Evolutionary Biology
• Behavioral Ecology

Background:

• Batesian mimicry involves harmless species mimicking defended ones to avoid predators.
• Mimicry theory predicts spatial overlap between mimics and models, but evidence for broader associations is growing.
• It's unclear if polymorphic mimics track individual models or entire communities of defended species.

Purpose of the Study:

• To investigate spatial associations between polymorphic hoverfly mimics (Volucella bombylans) and their putative bumblebee (Bombus sp.) models in Norway.
• To determine if mimic occurrences are more strongly linked to specific models or broader Bombus assemblages.
• To test whether mimic-model relationships operate at the individual species or community level.

Main Methods:

• Utilized species distribution models based on presence and pseudoabsence data.
• Quantified geographic distributions and spatial overlap of three V. bombylans morphs and three Bombus sp. model groups.
• Tested associations between mimic occurrences and habitat suitability of putative models versus alternative Bombus species.

Main Results:

• All three hoverfly morphs exhibited spatial overlap with Bombus model groups.
• Two morphs (V. b. "plumata" and V. b. "bombylans") showed positive associations with their putative models and other Bombus species.
• Bombus lapidarius showed the strongest association with two morphs, while V. b. "haemorrhoidalis" had no clear association with any single Bombus species.

Conclusions:

• Results do not support strict pairwise spatial mimic-model associations for V. bombylans morphs.
• Polymorphic V. bombylans morphs associate with broad Bombus assemblages, not individual model species.
• This suggests Batesian mimicry operates at the community level, driven by predator generalization across shared warning signals.