Parasitic Fly Implicated in Honey Bee Colony Collapse Disorder - CCD

Phorid Fly on Honey Bee

The parasitic Phorid fly may hold the key to understanding the sudden loss of honey bees around the world. Colony Collapse Disorder (CCD) is the name given to the mysterious cause of bees disappearing from their hive. Part of the difficulty in pinning it down is the wide variety of conditions that affect bees. Fungus, mites, stomach bacteria have been killing bees for decades. Many of these have been misdiagnosed as CCD.

One of the key symptoms is the disappearance of entire colonies of bees, leaving few if any workers, empty hives with combs filled with honey and young larvae still encapsulated, and yet no significant signs of dead bees in or around the hive.

As CCD has spread around the world, so has research to find a cause for this perplexing phenomenon. Suspected causes range from viruses, fungus, pesticides, and bee management techniques to queen breeding and many more possible CCD causes.

New research describing how Apocephalus borealis, a phorid fly, affects honey bees in a manner that may explain their sudden disappearance. Published in PLoS ONE, January 3, 2012

This particular species is native to North America where it usually targets bumble bees, yellowjacket wasps, and a even black widow spiders as its hosts. But since honey bees are not native to North America, it seems to have adapted to these new hosts.

One of the primary symptoms of bees attacked by the parasite is a change of behavior which cause them to leave the hive at night and subsequently die. The phorid fly larvae were found in bees attracted to lights at night in the San Francisco area where the study was performed. Unlike other insects attracted to the light, the bees were disoriented; walking in circles or unable to stand and eventually died. Whether the parasite changes the behavior of the bee to cause it to fly out at night or whether the parasitized bee leaves in an attempt to protect the hive is unknown and further study is needed to understand the process.

A serious concern is that with the honey bee host, the phorid fly has a new vector that may enable it to spread throughout the world. Nevertheless, understanding the life cycle and exactly how the phorid fly affects the bee, and how to prevent the attack is the goal of this research.

Image Credit: Image provided with original paper.
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Further reading

Dr. Andrew Core’s fly blog

Agricultural Research Service. Questions and Answers: Colony Collapse Disorder. Retrieved 12 January 2012, from https://www.ars.usda.gov/News/docs.htm?docid=15572