The Impact of Willow Flowering Time on Species Composition and the Number of Apoidea Pollinators

Pollinators are important to wild and cultivated plants, and the same plants are important to pollinators as well. A very important source of pollen and nectar to pollinators are willows (Salix spp.). The aim of this study was to demonstrate which Apoidea species are attracted by a species-diverse willow plantation (Poznan University of Life Sciences Willow Collection, Poland), the proportion of the number of honeybees to other species from the Apoidea superfamily visiting willow plantations, and whether the flowering date of male and female willow individuals affect the species composition and number of pollinators. Observations of willow phenology were carried out in the second year of willow growth, from March 9 to December 7, 2012. The insects were observed between April 6 and May 11, 2012. The results of this study showed 30 Apoidea species. Among 1591 Apoidea individuals, only 17 honeybee individuals were noted. The results show that the willow pollen production optimum occurred when the minimum air temperatures stopped dropping below zero. This parameter and this period are also related to the intensification of the occurrence of the noted insects. It can also be concluded that the pollen production season precedes the flowering optimum of female flowers and that the optimum flowering of female flowers is correlated with a significant increase in air temperature.