Colony

The mysterious drop in honey bee populations—often calledA colony collapse disorderA for lack of a more specific name—has generated a long list of suspects that includes mites, viruses, malnutrition, and even cell phone radiation. Two new studies published in Science suggest that neonicotinoids, a class of widely used insecticides, may belong at the top of the list.

That an insecticide kills insects like bees is not particularly surprising. Neonicotoinoids have already been partially banned in Italy, Germany, and FranceA for their possible role in colony collapse disorder. Still, it remains one of the most common pesticides: one neonicotoinid alone, imidacloprid, is authorized for use on over 140 crops in 120 countries. Results from the two new studies suggest that even doses that do not kill the bee immediatelyA can have enough ill effect to eventually cause colony collapse.

The first study in the UK compared 75 bumble bee colonies that researchers had exposed to varying levels of neonicotoinoids over 14 days. (Colony collapse disorder refers specifically to honey bees, but bumble bee numbers have beenA dropping off too.) After six weeks of foraging in the field, the colonies exposed to …