Pollenkitt is associated with the collectability of Malvoideae pollen for corbiculate bees

Pollen grains of Malvoideae (Malvaceae) which corbiculate bees cannot collect constitute a floral filter that excludes pollen-collecting bumble and honey from exploiting pollen resources. Although large, spiny are in fact harder to compact for collection by bees, morphology (e.g., grain diameter, spine length) is not itself reliable indicator collectability. In this study, we discovered two species, Anoda cristata Malope trifida, possess can be groomed collected bees. To gain insight into the underlying cause collectability pollen, tested adhesion bee setae found significantly less collectable A. M. trifida adhere bees’ compared uncollectable Hibiscus trionum. As primary mediator pollenkitt, viscous lipid-rich substance covering zoophilous plants, examined surface using cryo-SEM. Fresh were abundantly covered with pollenkitt also coated long spines formed liquid bridges between grains. Washing hexane removed all whereas washing water only on but syriacus. We hypothesise composition differs species pollen. Specific properties might elicit excessive viscidity affects insect visitors prevents