Honey bee-collected pollen in agro-ecosystems reveals diet diversity, diet quality, and pesticide exposure.

Megan J Colwell,Geoffrey R Williams,Dave Shutler,Rodger C Evans

doi:10.1002/ece3.3178

Megan J Colwell, Geoffrey R Williams + Show 2 more

Open Access

https://doi.org/10.1002/ece3.3178

Copy DOI

Abstract

European honey bees Apis mellifera are important commercial pollinators that have suffered greater than normal overwintering losses since 2007 in North America and Europe. Contributing factors likely include a combination of parasites, pesticides, and poor nutrition. We examined diet diversity, diet nutritional quality, and pesticides in honey bee‐collected pollen from commercial colonies in the Canadian Maritime Provinces in spring and summer 2011. We sampled pollen collected by honey bees at colonies in four site types: apple orchards, blueberry fields, cranberry bogs, and fallow fields. Proportion of honey bee‐collected pollen from crop versus noncrop flowers was high in apple, very low in blueberry, and low in cranberry sites. Pollen nutritional value tended to be relatively good from apple and cranberry sites and poor from blueberry and fallow sites. Floral surveys ranked, from highest to lowest in diversity, fallow, cranberry, apple, and blueberry sites. Pesticide diversity in honey bee‐collected pollen was high from apple and blueberry sites and low from cranberry and fallow sites. Four different neonicotinoid pesticides were detected, but neither these nor any other pesticides were at or above LD50 levels. Pollen hazard quotients were highest in apple and blueberry sites and lowest in fallow sites. Pollen hazard quotients were also negatively correlated with the number of flower taxa detected in surveys. Results reveal differences among site types in diet diversity, diet quality, and pesticide exposure that are informative for improving honey bee and land agro‐ecosystem management.

Highlights

Insect pollination contributed an estimated €153 billion to agriculture worldwide in 2005 (Gallai, Salles, Settele, & Vaissièrre, 2009)
Pollination services are how industrial apiculture generates the majority of its profits; industrialization of apiculture means that honey bees spend extended intervals in a single crop, and are transported successively from monoculture to monoculture, each of which contains a new suite of flowers and often a new suite of agricultural pesticides
When challenged with the microsporidian parasite Nosema ceranae, bees fed polyfloral diets lived longer than those on monofloral diets (Di Pasquale et al, 2013). These results suggest that when bees are stressed, pollen diversity may be more important than pollen quality

Summary

| INTRODUCTION

Insect pollination contributed an estimated €153 billion to agriculture worldwide in 2005 (Gallai, Salles, Settele, & Vaissièrre, 2009). When challenged with the microsporidian parasite Nosema ceranae, bees fed polyfloral diets lived longer than those on monofloral diets (Di Pasquale et al, 2013) These results suggest that when bees are stressed, pollen diversity may be more important than pollen quality. Our objectives were to quantify nutritional quality and pesticide residues of pollen to gain insights into real-world colony exposure. To our knowledge, this is the first study to simultaneously assess diversity, quality, and pesticide contamination of pollen

| MATERIALS AND METHODS

21–22 Aug 2011 in the three Maritime provinces of Canada

Findings

| DISCUSSION