Some of the consequences to honey bees that Wu found were delayed larval development and a shortened adult lifespan, which can result indirectly in premature shifts in hive roles and foraging activity.

Shortened bee lifespans dramatically change the dynamic of a hive. According to Sheppard, foragers are the bees that provide pollination and bring food back to a hive.

“A bee’s life span as a forager is on average only the last eight days of its life,” he said. “This research shows that, if raised with pesticide residues in the brood comb, an individual’s foraging life span is shortened by four days, a 50 percent cut.”

If there are not sufficient foragers, the colony makes up the deficit by using younger bees that are not physiologically ready. The result is a negative cascade through the hive all the way down to the larval bees because individual nurse bees must prematurely move toward foraging behavior and stop feeding larvae, Sheppard said.

In addition, according to Wu’s study, longer development time for bees may provide a reproductive advantage for Varroa destructor mites. Varroa mites are parasites that live in hives and prey on honey bees. The extended bee developmental period enables these mites to produce more offspring that devastate hives.

Wu’s research recently was published in the peer-reviewed online journal PLoS One. Find it at Learn more about entomology research at WSU by visiting