Data from: Floral community predicts pollinators' color preference: implications for Batesian floral mimicry

Animals that rely on nectar are expected to display floral trait
preferences correlating to the signals of nectar source flowers. Batesian
mimicry evolves to exploit these pre-existing signal-receiver
relationships, attracting pollinators through an adaptive resemblance to
specific co-occurring rewarding species. The nectar-feeding long-proboscid
flies of South Africa are pollinators for several deceptive orchid species
that are putatively Batesian mimics. We tested whether flies’ measured
color preference varied among communities providing different
nectar-source diets, which would indicate the necessary signal-receiver
conditions for the evolution of advergent Batesian mimicry. We introduced
artificial rewardless flowers into flowering communities that supported
divergent nectar-diets in resident flies and inferred floral trait
preferences of a long-proboscid fly species (Prosoeca ganglbaueri) from
visitation behavior to these artificial flowers. The experiment showed
that the preference of flies for white versus pink was strongly predicted
by the colors of flowers most commonly visited by flies at a site.
Furthermore, generalization in preference was positively correlated with
the variance in nectar-community hue, i.e. flies showed more generalized
preference in more spectrally diverse flower communities. The floral tube
length of local nectar sources also influenced how readily the flies
probed the artificial flowers during attempted foraging. These results
support the hypothesis that nectarless orchids pollinated by P.
ganglbaueri experience selection for traits that exploit site-specific
mutualistic relationships between fly pollinators and their local floral
communities.