The tactic and floral constancy of foraging bumblebees: pure legitimate foragers, pure nectar-robbers, and mixed tactic individuals visiting one or more host species
PublisherThe University of Arizona.
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AbstractFloral visitors in a Colorado bumblebee community engage in two main foraging tactics: nectar-robbing and legitimate foraging. An individual may employ one tactic consistently throughout a foraging bout or switch and may visit one consant host species or multiple. In order to understand foraging strategies, tactic and floral constancy must jointly be investigated with pollen and nectar foraging. I do so in this second ever study to compare floral visit observations with pollen load compositions. I found that nectar-robbers carried pollen less or as often as legitimate foragers, depending on robber and host species. This suggests that pollen-carrying robbers are mixed tactic individuals that could, in one foraging bout, cheat and cooperate with its plant partner. Visitors were observed switching tactic within a host species and switching tactic between host species. Both robbers and legitimate foragers carried pollen from the same host species they visited for nectar when that host species could be both robbed for nectar and legitimately foraged for pollen. These results suggest that tactic switching is more common than previously thought and that floral constancy is frequently maintained across tactic switches, unless host floral morphology constrains behavior and forces a host switch.
Degree ProgramHonors College
Ecology & Evolutionary Biology