INSIGHTS ON POLLEN DIVERSITY OF HONEY BEE (APIS MELLIFERA L.) COLONIES LOCATED IN VARIOUS AGRICULTURAL LANDSCAPES

摘要

In an effort to identify landscapes that provide honey bee (Apis mellifera L.) colonies with the most sustainable pollen sources, we conducted an extensive palynological analysis on trapped pollen collected from honey bee hives located in various agricultural landscapes. Collected pollen, honey bee preferences, and potential exposure to pesticides through collected crop pollen were investigated. We collected 128 trapped pollen samples throughout the 2015 season from 16 honey bee colonies distributed in four different agricultural landscapes: a high agricultural (High-AG) area, a moderate agricultural (Mod-AG) area, a low agricultural (Low-AG) area with high levels of urban activity, and a nonagricultural (Non-AG) area. We carried out comprehensive pesticide residue analyses on representative sets of pollen samples. Our results indicate that the Low-AG area with high levels of urban activity had significantly greater pollen diversity than other locations and had the least fluctuation in pollen types across the season. We recorded the lowest pollen diversity in both the High-AG and Non AG areas with only 23 pollen types, suggesting that both settings lack a diversity of plant species attractive to honey bees. Noncrop pollen collected by honey bees largely exceeded the crop pollen in number and amount, indicating that bees' pollen-diet relies on a large spectrum of noncrop flowers. None of the pesticide residues identified in the pollen samples approached the honey bee 50% lethal dose concentrations.