This new weight loss secret will make your apiarist hate you!

Varroa destructor(ew)

What's a Varroa mite's favorite blood type to drink? Bee-positive! Varroa destructor (public bee enemy #1) are red-brown external parasites of honey bees. These super tiny bugs feed mostly on larvae and pupae. Previously, they were thought to suck the "blood" of bees, known as hemolymph. Scientists believe that these vampires are what cause the malformation and weakening of honey bees along with the transmission of viruses. 

Recently though, experiments with fake bee larvae have revealed that our favorite little bloodsucking vampires might actually be flesh-eating werewolves. 

Entomologist Samuel Ramsey conducted a year-long experiment developing artificial bee larvae that let him test how well mites survived when fed different amounts of fat from an organ called the "bee fat body" versus hemolymph. Mites lived for an average of 1.8 days on pure hemolymph. The few mites able to survive the entire seven-day tests ate 50 percent to 100 percent fat. 

Artificial Bee Larvae

Other experiments also provide evidence for Ramsey's werewolf parasites. Feeding adult bees two stains- a red stain for bee fat and a yellow stain for hemolymph (bee blood)- also shows that mites are targeting adult fats. Microscopic images of the mites’ multipart guts taken after feeding glowed red, the researchers found. When the parasites fed on bees with only their hemolymph stained, the mite guts looked dim.

GUT GLOW Microscope images revealed that mites that fed on bees with only their hemolymph stained had ghostly dim guts (left), similar to starved mites used as a control (middle). But mites that fed on fat-stained bees had glowing guts full of red fat (right).

Paying attention to fat lets us in on how mites damage bees. The bee fat body detoxifies pesticides and helps in the development of the unusually long-lived generation needed to survive winter. Mites eating the organ may reduce bees’ immune response, worsening damage from the viruses they spread. These symptoms of flesh-eating mites match up very closely with what scientists believe happens with bloodsucking mites. 

Microscopic view of  a Varroa destructor (shown in pink) wedged under a bee’s protective plate

Along with his evidence supporting the idea of fat eating Varroa mites, Ramsey believes that there is evidence against the blood drinking kind. Looking at Varroa anatomy, you can see that they don’t have the more flexible body that can swell with a lot of incoming fluid or a gut specialized for elaborate liquid filtering that many other bloodsuckers do. And according to Ramsey, insect hemolymph is a weak, watery choice for exclusive nutrition. 

Although the evidence for the idea of werewolf mites is growing, so are the questions. Some scientists still believe that the tiny little parasites hurting honey bees are vampires. Other scientists have yet to decide between Team Edward and Team Jacob. And the honeybees... probably don't care about what type of parasite it is. But hopefully, this discussion on what's hurting the honeybees will lead us to find out ways to help them. 

                                                                                                                                         -C.J George