Does intraspecific behavioural variation of pollinator species influence pollination? a quantitative study with hummingbirds and a neotropical shrub

Abstract

Floral visitors differ in their efficacy as pollinators, and the impact of different pollina-tor species on pollen flow and plant reproduction has been frequently evaluated. Incontrast, the impact of intraspecific behavioural changes on their efficacy as pollina-tors has seldom been quantified.•We studied a self-incompatible shrub Palicourea rigida (Rubiaceae) and its humming-bird pollinators, which adjust their behaviour according to floral resource availability.Fluorescence microscopy was used to access pollen tube growth and incompatibilityreaction in pistils after a single visit of territorial or intruder hummingbirds in twopopulations. To characterise the plant populations and possible differences in resourceavailability between areas we used a three-term quadrat variance method to detectclusters of floral resources.•Within-species variation in foraging behaviour, but not species identity, affected polli-nator efficacy. Effectively, hummingbirds intruding into territories deposited morecompatible pollen grains on P. rigida stigmas than territory holders in both studyareas. Additionally, territory holders deposited more incompatible than compatiblepollen grains.•Our results imply that intraspecific foraging behaviour variation has consequences forpollination success. Quantifying such variation and addressing the implications ofintraspecific variability contribute to a better understanding of the dynamics and con-sequences of plant–pollinator interactions.