Honey Bee Diet Impacts Gene Expression in Insects: You Are What You Eat

During lean times, many beekeepers feed their honey bees with sucrose or high-fructose corn syrup. Yet this particular practice has come under scrutiny lately as bee populations continue to decline. Now, scientists have taken a closer look at the diet of the Western honey bee and have found that significant differences occur depending on what the bees eat.

The researchers examined energy storage tissue in bees called the fat body, which functions like the liver and fat tissues in humans and other vertebrates. They limited their analysis to foraging bees, which are older, have a higher metabolic rate and less energy reserves in the form of lipids stored in the fat body. This makes the bees more dependent on a carbohydrate-rich diet.

"We figured that the fat body might be a particularly revealing tissue to examine, and it did turn out to be the case," said Gene Robinson, who helped perform the new analysis, in a news release.

The scientists examined gene activity in response to feeding with honey, high-fructose corn syrup (HFCS) or sucrose. In the end, they found that the honey-fed bees had a very different profile of gene activity in the fat body than those relying on HFCS or sucrose. In fact, hundreds of genes showed differences in activity in honey bees consuming honey compared with those fed HFCS or sucrose. These differences remained even in an experimental hive that the researchers discovered was infected with deformed wing virus.

"Our results parallel suggestive findings in humans," said Robinson. "It seems that in both bees and humans, sugar is not sugar-different carbohydrate sources can act different in the body."

So what did these different genes do? Some of the genes that were activated differently in the honey-eating bees have been linked to protein metabolism, brain-signaling and immune defense. This could mean that honey may, in fact, be better for bees and could increase the activity in genes that help bees break down potentially toxic substances, such as pesticides.

"Our results further show honey induces gene expression changes on a more global scale, and it now becomes important to investigate whether these changes can affect bee health," said Robinson.

The findings are published in the journal Scientific Reports.