Effects of Exposure to Multiple Agrochemicals in Honeybees (Apis mellifera)

Abstract

The Honeybee (Apis mellifera) is one of the most economically and environmentally valuable pollinators today. Beekeepers have often been threatened by periodic high colony losses, but the ability to attribute them to specific practices or pathogens and parasites has allowed for the mitigation of such losses fairly efficiently and quickly. However, this has not been the case with the more recent losses that have decimated North American and European apiaries since 2006. The phenomenon has been named Colony Collapse Disorder and it differs from previously described losses in that it is characterized by the unexplained disappearance of large numbers of individuals from seemingly healthy hives. In this study it was hypothesized that an increased mortality is expected as the number of agrochemicals to which individuals are exposed increases. Data on colony losses and pesticide use was gathered for 49 Californian counties, and a correlation analysis performed. A significance of 0.086 suggested that a moderate relationship could be demonstrated, meaning that the threat posed by pesticides to honeybees is expected to rise as the variety of these pesticides is increased, possibly due to synergism. In light of such results, further investigation of the problem is recommended, and the development of a better understanding of the impacts of sublethal doses of pesticides on honeybees, as well as of the ways these interact to possibly increase their toxicity to beneficial species is necessary.