Royal tell-all: Queen’s affairs dictate hive health
By Scott Elliott, National Institute of Food and Agriculture
For years investigators have been trying to discover the cause of the massive honey bee die-off known as Colony Collapse Disorder (CCD). While there are several potential environmental culprits, communication between queen and worker bees may be one possible answer to this serious problem.
An international team of researchers led by Penn State University has found that a queen bee’s effectiveness at communicating “availability” to potential mates could be a key factor in the future well-being of the colony. Queens use chemicals called pheromones to provide detailed information to potential mates on their reproductive status. That information is important because queen bees that mate with several males provide their colonies greater genetic diversity and a higher chance of survival. On the other hand, these pheromones also signal when a queen has not mated well—and worker bees tend to remove poorly-mated queens.
The U.S. Department of Agriculture’s (USDA) National Institute of Food and Agriculture provided nearly $400,000 to fund the project. The team, comprised of researchers from Penn State, North Carolina State University, and Tel Aviv University, investigated the effects of four naturally-occurring stressors—mating number, nutrition, virus infection, and environmental toxins—on queen and worker physiology, behavior, and social interactions.
“We found little impact of nutrition, pesticides and viruses on queen pheromone production and worker responses to the pheromone, which suggests that queens are really adapted to signaling their mating status,” said Dr. Christina Grozinger, director of Penn State’s Center for Pollinator Research.
If worker bees feel the need to oust poorly-performing queens, it’s bad business for beekeepers. It can take three weeks for a new queen to become mature enough to lay eggs and another three weeks for worker bee larvae to mature to adulthood and contribute to the hive.
Honey bees are the primary pollinators to 100 key agricultural crops and are responsible for about $15 billion in added crop value each year. CCD became a matter of concern in the winter of 2006-2007 when beekeepers in the United States reported huge losses of adult bees from their hives. Although losses were less severe through the winter of 2013-14, annual losses through 2011 were reported at about 33 percent.
“Queen pheromone regulates a lot of other aspects of worker behavior and physiology, including how fast workers mature and transition from taking care of developing larvae to foraging outside the hive,” Grozinger said. “It is possible that changing the quality of the pheromone could have large-scale effects on colony organization and survival.”
Together with researchers at MIT, the Penn State team is now examining whether and how low population sizes (which result from poor queen mating), in combination with other stressors, can lead to poor colony performance and colony collapse.
Tune in to the USDA’s “Bee Cam” to watch honeybee activity at the People’s Garden Apiary in Washington, DC. Bee Cam provides live coverage 24-7.