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

Batesian mimicry enables harmless species to evade predation by resembling defended models. Although mimicry theory predicts that mimics should broadly co-occur with their models, increasing evidence suggests that mimic-model associations may extend beyond individual model species, and it remains unclear whether polymorphic mimics spatially track individual model species or broader communities of defended prey across landscapes. We used species distribution models based on presence and pseudoabsence data to quantify the geographic distributions and spatial overlap of three hoverfly mimics (Volucella bombylans) morphs and three putative bumblebee (Bombus sp.) model groups across Norway and tested whether mimic occurrences were more strongly associated with their putative models than with alternative Bombus species. All three hoverfly morphs showed spatial overlap with Bombus model groups. Occurrence of V. b. "plumata" and V. b. "bombylans" was positively associated with habitat suitability of their putative Bombus models and other Bombus species. However, Bombus lapidarius sensu lato showed the strongest spatial association with both morphs, whereas V. b. "haemorrhoidalis" showed no clear association with any Bombus species. Overall, our results do not support strict pairwise spatial associations between V. bombylans morphs and their Bombus models. Instead, they suggest that polymorphic V. bombylans morphs associate with broad Bombus assemblages rather than individual model species. This pattern is consistent with Batesian mimicry operating at the level of broader mimicry communities, where predator generalization across shared warning signals may reduce selection for strict model-specific spatial associations.