Bees and Pesticides

Honey bees (Apis mellifera L.) are the main pollinating agents for numerous plants and fruit trees and hence, play a key role in agriculture and more generally in the maintenance of ecological biodiversity. They are mostly affected farm animals by pesticides. Indeed, pesticides work in two ways to reduce bee populations. First, many pesticides used in crop production are highly toxic to these social insects. Second, the use of herbicides can reduce the acreages of useful plants for the bee activity. Pesticides damages to honey bee colonies take different forms. Honey bees may be poisoned when they feed on nectar or pollen contaminated by pesticides. Bees may also be poisoned when they fly through a cloud of pesticide dust or spray or walk on treated parts of plant. Sometimes, colonies in the hives can be directly affected, but most commonly only field bees are killed or have their physiological functions altered. Toxicity and hazards of 158 pesticides to Apis and non-Apis bees are well reviewed in a study of Devillers et al. (2003).