Problems for Pollinators, Part 1: Pesticides

In agriculture, pesticides are widely used to control populations of agricultural pests and improve the overall quality and production of crops. Insecticides that contain neonicotinoids cause neurotoxic effects and are therefore effective in controlling pests such as aphids and leafhoppers which digest plant material containing the neurotoxins (Blacquiere, Smagghe, van Gestel, & Mommaerts, 2012). Neonicotinoids are widely expressed in plant tissues - including flowers and their pollen - and this is a threat to the survival of insect pollinators that are affected by the compounds within these pesticides..

Neonicotinoids have been demonstrated to have both lethal and sublethal short-term effects on bees in numerous laboratory studies. In a multi-species analysis by Woodcock et al. (2016), it was observed that areas in which oilseed rape crops were exposed to neonicotinoids had a negative correlation with the population persistence of species who forage on oilseed rape. This suggests that the sublethal effects of neonicotinoids may scale up to have larger, negative impacts on bee biodiversity and may lead to local population extinctions in the long-term (Woodcock et al., 2016).

However, because field studies with realistic doses have been generally limited, neonicotinoids have not been able to conclusively demonstrate their risk to honeybee bee survival in the long-term. Because field-realistic studies are lacking, Blacquiere et al. (2012) suggest that the demonstrated toxicity of neonicotinoids on laboratory studies and the potential for negative impacts on pollinator populations warrants further study and observation in order to develop a risk assessment scheme for the further application of neonicotinoids in pest management.

Click here or on the diagram to see the full infographic series about how pesticides impact bees, plants, soil, honey, and our food supply!

---

Blacquière, T., Smagghe, G., van Gestel, C., & Mommaerts, V. (2012). Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment. Ecotoxicology, 21(4), 973-992. http://dx.doi.org/10.1007/s10646-012-0863-x

Earthjustice. (2017). Infographic: Bees' Toxic Problem. Earthjustice.org. Retrieved from http://earthjustice.org/features/infographic-bees-toxic-problem

Woodcock, B., Isaac, N., Bullock, J., Roy, D., Garthwaite, D., Crowe, A., & Pywell, R. (2016). Impacts of neonicotinoid use on long-term population changes in wild bees in England. Nature Communications, 7, 12459. http://dx.doi.org/10.1038/ncomms12459