Penn State researchers have found that native pollinators, such as wild bees and wasps, are infected by the same viral diseases as honey bees and that these viruses are transmitted via pollen. Their research was published on December 22nd in PLoS ONE, an online open-access journal for the communication of all peer-reviewed scientific and medical research.

This multi-institutional study provides new insights into viral infections in native pollinators, suggesting that viral diseases may be key factors impacting pollinator populations.

According to Diana Cox-Foster, co-author and professor of entomology at Penn State, pollinator populations have declined for various reasons, including ribonucleic acid (RNA) viruses, which are emerging as a serious threat. “RNA viruses are suspected as major contributors to Colony Collapse Disorder (CCD), where honey bee colonies die with few or no bees left in the hives.  Recent detection of these viral species in bumble bees and other native pollinators indicates a possible wider environmental spread of these viruses with potential broader impact,” explains Cox-Foster.

The researchers studied viral distributions from pollen pellets of honey bees and other pollinators collected from flowering plants in Pennsylvania, New York, and Illinois in the United States. “For the first time, RNA viruses such as deformed wing virus, sacbrood virus and black queen cell virus were detected in pollen pellets collected directly from forager bees,” said Cox-Foster. “Pollen pellets from several uninfected forager bees were detected with virus, indicating that pollen itself may harbor viruses. The viruses in the pollen and honey stored in the hive were demonstrated to be infective, with the queen becoming infected and laying infected eggs after these virus-contaminated foods were given to virus-free colonies.”

The detection of RNA viruses in other pollinators, including bumble bees, solitary bees and wasps, suggests that viruses might have a deeper impact on ecosystem health, given that these pollinators are essential to most plants for seed set and production of fruits, nuts, berries, and vegetables. The findings are important to the public and scientific community worldwide, given pollinators’ role in agriculture and the environment and recent declines in native pollinators. The findings also raise biosecurity issues because pollen is currently being imported into many countries to feed honey bees used in agricultural pollination.

For more information on pollinator research, visit The Penn State Center for Pollinator Research web site at http://ento.psu.edu/pollinators. The center, which is devoted to the study of pollination, pollinators and pollinator management and protection, comprises 26 independent faculty, including researchers, educators, Extension specialists and outreach coordinators, spanning multiple departments and colleges at Penn State.