Washington, DC–(ENEWSPF)–November 20, 2015. French scientists say that they have found the “missing link” between laboratory studies and field studies that assess the adverse effects of neonicotinoid (neonic) insecticides on bees. The study, published in Royal Society Journal Proceedings B, evaluates the effects of neonics on honey bees in field trials. After 15 years of research into the effects of neonicotinoids on bees, researchers had identified a gap between the results of toxicity assessments on individual bees in the laboratory and impacts seen at the colony level in the field. The new two-year study made two discoveries: First, they found that field exposure to thiamethoxam combined with imidacloprid contamination is associated with a significant excess mortality in individual free-ranging bees. Second, while colonies appeared to be able to compensate for the excess mortality and preserve population size and honey production, this was done at the expense of a change in brood laying patterns. Thus, this study provides an explanation for the “missing link” in the discrepancies between labs studies and field studies, where the former establishes harmful and fatal effects that had yet to be replicated in real-life conditions. Because the bees responded to the increased mortality with selective population regulation, the proportion of male bees declined significantly, representing an abnormality with potentially widespread impacts for the health of honey bee colonies
