I am uncertain about the claim to be the first research “to demonstrate the sub-lethal effects of pesticide residue exposure on honey bees” – I believe that there may be a growing body of research that demonstrates this.
Recently published research is the first to demonstrate the sub-lethal effects of pesticide residue exposure on honey bees, which play a critical role in the production of one third of the food that human’s consume.
The pesticides involved in Wu’s study include those used by beekeepers, growers and homeowners. They include miticides, insecticides, fungicides and herbicides. The accumulation occurs because beekeepers reuse combs to save on the expense of replacement.
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.