Attachment of honeybees and greenbottle flies to petal surfaces

Abstract

Flower surfaces play a key role in the interaction with pollinators acting as signals and landing sites to attach to. To test attachment, Carniolan honeybees and greenbottle flies were used. Both species represent pollinators equipped with smooth or hairy tarsal attachment devices, respectively. A combination of microscopic methods and traction force measurements was applied in order to understand and evaluate the efficiency of pollinator attachment to a variety of petal surfaces. Although the petal surface texture influenced the attachment, coevolutionary relationships or adaptations between flower surfaces and pollinator tarsi could not be confirmed. Since pollinators appear to be opportunistic, they are expected to attach to a variety of flower surfaces. Rougher surfaces, including conical and papillate epidermal cells, significantly increased the foothold of flies and honeybees, while flat, tabular epidermal cells covered with microstructures like cuticular folds and epicuticular wax crystals impaired attachment. Carniolan honeybees generated larger forces than greenbottle flies, but the latter showed higher safety factors. However, tendencies in attachment ability toward sufficient and insufficient substrates are similar in flies and bees.