Two studies reported in Science examined the relationship between bee deaths, Colony Collapse Disorder (CCD) and one of the most widely used crop pesticides in the world, neonicotinoids. The articles were summarized at the Eureka Alert web site on March 29, 2012.
Neonicotinoids act on the nervous system of insects but have a very low toxicity to mammals.
Penelope Whitehorn of the University of Stirling in Stirling, U.K led a comparison study between colonies of bumblebees, Bombus terrestri.One colony had been exposed to doses of the neonicotinoid (imidacloprid) that were similar to those they would receive in a farm environment. The exposed bees produced 85 percent fewer queens, were eight to twelve percent smaller, and weighed less. All these conditions could lead to CCD with the low number of queens being a major contributor to a slower and lower rate of colony spread and population growth.
Mickaël Henry of the French National Institute for Agricultural Research (INRA) in Avignon, France and colleagues found that free-ranging honeybees exposed to a a sublethal dose of the pesticide thiamethoxam seemed to have lost their homing instinct as a result of exposure the pesticide and died at a 50 to 66 percent greater rate than unexposed free-ranging honeybees. This study demonstrates a higher similarity to CCD.
The bees in the second study were tracked with tiny Radio-frequency identification (RFID) microchips that were glued to each bee’s thorax.
Both teams of scientists seek to dissuade farmers all over the world from using neonicotinoids on and around flowering trees and plants to prevent further bee loss. Bee pollination is mandatory for the success of fruit, vegetable, and flower farmers.