9. Pesticides and pollinators
Negative consequences of pesticide interactions with bees pollinating crops are a serious concern. Methods to assess risk to individual bees and colonies from toxic effects of chemicals are established, and methods are expanding to include sublethal behavioural effects such as disorientation of foragers (see Medrzycki et al., 2013). Obviously any environmental toxins which affect the health of a colony may impact the effectiveness of the colony as a pollinating unit by altering (especially diminishing) foraging activity.
Other effects can come from purposeful use of chemical attractants and repellents on a blooming crop. The effects of such chemicals can be measured using techniques to determine bee densities in whole fields or orchards (sections 5.1. or 5.2.) or, more commonly, in small plots. Similar small-plot techniques can be used to gauge any pollination-related effects from GMO crops that potentially arise from altered secretion of nectar and shedding of pollen.