In 2006, bee colonies started failing at a rate never seen before. Entire colonies died. Farmers feared a shortage of bees to pollinate their crops. The cause of this phenomenon, known as colony collapse disorder, remains a mystery despite intense effort. HHMI investigator Joe DeRisi is using his expertise on viruses to tackle the problem.
“Attempts to examine the cause of the bee colony collapses were confounded by the fact that very little was known about viruses in bees, period,” says DeRisi.
So DeRisi and his colleagues at the University of California, San Francisco, decided to follow a convoy of semitrailer trucks with 70,000 beehives as it drove around the country during its annual trek to pollinate crops. With the help of experienced commercial beekeepers, bee samples from 20 designated hives were collected each week throughout the year. Using a specially designed microarray that allows rapid screening for viruses and other pathogens of insects, they monitored pathogen incidence at different times of year in different hives.
“We were leveraging a lot of the same skills and technology that we use to look at human medicine and veterinary medicine,” says DeRisi, “and now applying that to insects.”
By the end of the year, the team had tracked all known bee viruses and identified four more, they reported in PLoS One on June 7, 2011. Two in particular stood out. The scientists named them Lake Sinai virus 1 and 2, after a South Dakota lake near where the bees were collected. Surprisingly, Lake Sinai virus 2 was found to be the most abundant pathogen in the bees, reaching levels of greater than 1 billion copies per bee in the winter.
The data collected by the DeRisi lab don’t solve the mystery of why bees are dying. But they offer a baseline for scientists who continue to track bee viruses. “This study provides a foundation from which to work,” says DeRisi. Now the team can continue following bees and begin correlating viruses with colony collapse to better understand current and emerging threats. It’s a step toward keeping bees healthy.