Honeybee Diets Help Them Resist Deadly Pesticides

Honeybee diets that consist of natural pollen can help make the more resistant to deadly pesticides compared to feeding them an artificial diet, new research says.

While foraging for flowers, honeybees are exposed to hundreds of pesticides every day, like neonicotinoids, and now scientists are fairly certain that they are the leading cause behind a drastic decline in honeybee populations first noticed nearly a decade ago. Now, this new study shows that such harmful chemicals can cause changes in expression of genes involved in combating pesticides.

"Our study demonstrates that exposure to non-lethal doses of at least two of these pesticides causes large changes in the expression of genes involved in detoxification, immunity and nutrition-sensing," researcher Christina Grozinger said in a statement. "This is consistent with results from previous studies that have found that pesticide exposure compromises bees' immune systems."

Now, researchers have found that diet significantly impacts how long bees can survive when given lethal doses of a pesticide.

A team from Penn State decided to feed honeybees a pollen diet or an artificial diet - either a soy protein or no protein diet. While also subjecting them to the pesticide chlorpyrifos, which is frequently used to control pests in agricultural crops, they noticed that bees consuming the pollen diet were less sensitive to chlorpyrifos compared to the control group of bees.

What's more, it turns out pesticide exposure can impact the expression of genes that are sensitive to diet and nutrition. For instance, upon feeding honeybees either the pesticide coumaphos or fluvalinate for a period of seven days, Grozinger and her colleagues noticed significant changes in 1,118 transcripts - or strands of RNA - in the experimental group.

"These transcripts included genes involved in detoxification, immunity and nutrition," said researcher Daniel Schmehl.

With this new information in mind, scientists may be able to better understand the dying honeybee problem. The US Fish and Wildlife Service and the National Park Service have already began to phase out the use of neonics. Some big name garden retailers like BJ's Wholesale have also sworn off the use of these harmful pesticides.

The latest results are described in the Journal of Insect Physiology.