Queen honeybees fed syrup laced with the pesticide imidacloprid laid significantly fewer eggs—between a third and two-thirds as many—than unexposed bees, according to a new study by University of Nebraska researchers published in the journal Science Reports.
“The queens are of particular importance because they’re the only reproductive individual laying eggs in the colony,” said lead author Judy Wu-Smart, assistant professor of entomology a the University of Nebraska. “One queen can lay up to 1,000 eggs a day. If her ability to lay eggs is reduced, that is a subtle effect that isn’t (immediately) noticeable but translates to really dramatic consequences for the colony.”
Imidacloprid is a neonicotinoid, a class of pesticides that many scientists think has contributed to the decline of bee populations in recent years.
The study also found that colonies that consumed the imidacloprid had “larger proportions of empty cells, the signature hexagonal hollows that serve as cribs for honey bee broods.” Tainted colonies also “stored far less pollen, which they convert into a “bee bread” that provides crucial protein for recently hatched larvae.”
“And the honey bee equivalent of biohazard containment — the removal of mite-infested or diseased pupae before they can infect the hive — also suffered.” This made the colonies more susceptible to pests and pathogens.