AgCenter research examines how viruses affect honey bees’ vision

From left, LSU AgCenter entomologist Daniel Swale, USDA-ARS entomologist Michael Simone-Finstrom and AgCenter entomologist Nathan Lord examine bees at the USDA-ARS Honey Bee Breeding, Genetics and Physiology Research Unit in Baton Rouge on Jan. 24, 2022. Photo by Olivia McClure/LSU AgCenter

BATON ROUGE, La. — Viruses are one of many factors scientists believe are contributing to the collapse of honey bee colonies. Not only do the viruses kill bees; infections also can alter their eyesight and what foods they are attracted to, leaving their colonies with inadequate nutritional content.

Armed with a recently awarded U.S. Department of Agriculture National Institute of Food and Agriculture grant, LSU AgCenter researchers are working to learn more about how viruses affect bees’ vision and whether there are ways to help them recover from infections and return to normal foraging behavior.

AgCenter entomologist Daniel Swale is working on the project with fellow entomologists Nathan Lord, of the AgCenter; Michael Simone-Finstrom, of the USDA Agricultural Research Service Honey Bee Breeding, Genetics and Physiology Research Unit in Baton Rouge; and Troy Anderson, of the University of Nebraska-Lincoln. The $272,717 grant will fund their research through December 2023.

The scientists are focusing on the effects of two viruses: deformed wing virus, which causes bees to grow short, stubby wings unsuitable for flying, and Israeli acute paralysis virus, which causes neurological problems such as twitching and can kill bees within 24 to 48 hours of infection. The viruses are transmitted by mites.

In infected colonies, Swale and his colleagues have noticed bees returning with unusual food choices.

“They’re bringing back different pollens and different fats when they are infected with these viruses,” he said. “It turns out that these viruses migrate to their eyes, and when the bees are infected with deformed wing virus and IAPV, we get different attractions to different colors. It shifts the spectrum of attractiveness.”

They’ve also found evidence of physiological changes in infected bees’ eyes that interfere with vision. They can’t see colors correctly and end up bringing back pollens and fats they wouldn’t normally select.

“The eyes are one of the key components to successful foraging,” Swale said.

In the grant project, he wants to find out how to enhance bees’ immune response to viruses and whether it’s possible to help infected bees maintain their vision, which also could help them continue to forage properly.

Swale has previously studied physiological channels that transport potassium ions through insects’ bodies. He said they may represent an opportunity to help bees cope with the effects of viruses. For example, therapeutic products targeting the channels potentially could be developed after additional research.

“Potassium ion channels do seem to regulate the antiviral response system as well as reduce the amount of virus that reaches the eyes,” Swale said. “It looks like if we’re able to modulate the potassium channels in the correct way, we can restore visual acuity and visual performance in these bees.”

https://www.lsuagcenter.com/articles/page1643645654417