Pseudo-Honey Diet to Blame for Dying Honeybees?

Beekeepers who feed their bees pseudo-honey, meaning high-fructose corn syrup or sucrose in times of honey shortage, may be contributing to the annual honeybee die-off, researchers explain.

This practice has recently come under close scrutiny with honeybee populations currently declining in the United States and Europe, and rightfully so. A new study described in the journal Scientific Reports noticed changes in gene activity in response to diet in the Western honeybee (Apis mellifera), and found significant differences occur depending on what the bees eat.

Some believe pesticides are to blame for the dying honeybees, but this research takes a look at an energy storage tissue in bees called the fat body, which functions like the liver and fat tissues in humans and other vertebrates.

"We figured that the fat body might be a particularly revealing tissue to examine, and it did turn out to be the case," study lead author Gene Robinson, an entomology professor at the University of Illinois, said in a statement.

Researchers focused on foraging bees, which are older have a higher metabolic rate and less energy reserves, making them more dependent on carbohydrates for their diet compared to their younger nest-mates.

"We reasoned that the foragers might be more sensitive to the effects of different carbohydrate sources," Robinson explained.

When analyzing gene activity in response to feeding with honey, high-fructose corn syrup (HFCS), or sucrose, researchers found that those bees fed honey had a very different profile of gene activity in the fat body than those relying on "pseudo" or "blended" honey.

Hundreds of genes showed differences in activity in honeybees consuming honey compared with those fed HFCS or sucrose.

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

Some of the affected genes were also related to protein metabolism, brain-signaling and immune defense. With respect to the latter, a 2013 study conducted by the University of Illinois reported that some substances in honey increase the activity of genes that help the bees break down potentially toxic substances such as pesticides.

This most recent research suggests that pesticides indirectly may be causing honeybee decline, but the root of the cause could, in reality, be their diet.