Reloading the revolver – male fitness as a simple explanation for complex reward partitioning in Nasa macrothyrsa (Loasaceae, Cornales)

摘要: Reward partitioning and replenishment specific mechanisms for pollen presentation are all geared towards the maximization of number effective pollinator visits to individual flowers. An extreme case an apparently highly specialized plant‐pollinator interaction with thigmonastic has been described morphologically complex tilt-revolver flowers Caiophora arechavaletae (Loasaceae) pollinated by oligolectic Bicolletes pampeana (Colletidae, Hymenoptera). We studied floral biology Nasa macrothyrsa in field glasshouse, which very similar morphology, but is polylectic Neoxylocopa bees (Apidae, investigated presence anther presentation, visitor behaviour (pollinators nectar robbers), co-ordination flower replenishment. The aim this study was understand whether morphology can be explained a pollination syndrome, or alternative explanations offered. results showed that i.e. new rapidly (<< 10 min) presented after visit. Nectar secretion independent removal averages 7‐14 m Lh ‐1 . flowers, however, fail exclude either native (hummingbirds) introduced (honeybees) robbers, nor does actively collect presented. findings do not support causal link between functionality Loasaceae pollination. Rapid best theory: large proportion pollinators coming shortly previous visit find little more likely move on different plant. rapid ensures these valuable ‘hungry pollinators’ dusted small loads, thus increasing male fitness plant likelihood siring outcrossed offspring. © 2010 Linnean Society London, Biological Journal Society, 2010, 100, 124‐131.