Bumblebee Queens Travel Far And Away Before Starting New Homes
Brett Smith for redOrbit.com – Your Universe Online
The study was based on observations of five different species, including four common and one rare species, in nearly 7.7 square miles of farmland in southern England. The researchers found that queens nesting near one another were barely related or completely unrelated for all five species.
The study team noted that their work provides essential information on the biodiversity of bumblebees, which are expected to be impacted by changing climates around the world.
“Queens, not workers, are the ones that pass on their genes to the next generation,” explained study author Stephanie Dreier, a researcher from the Zoological Society of London. “Knowing how far a queen flies from her birthplace to set up her own colony is therefore crucial for understanding how bumblebees use the landscape.”
Bumblebee colonies exist in short cycles and at the end of the cycle, before winter, new queens are produced. These young queens mate, hibernate and set up new colonies the following spring.
Because bumblebee nests are difficult to find, even for expert researchers, the study team sampled DNA from daughter workers caught foraging in the study area. After noting where the daughter bees were captured, the team was able to develop a map that modeled where each nest was based on a DNA analysis.
The study team found that queens originating from the same nest fly long distances to set up a nest of their own.
“We knew that bumblebee queens could fly long distances, but these results show that new queens frequently disperse widely, perhaps several kilometers away from their birthplace, before starting their own nest,” said study author Claire Carvell, an ecologist at the Centre for Ecology & Hydrology. “This suggests that populations of both common and rare species can be genetically well mixed through queen dispersal, and that managing landscapes with flower-rich habitats that are well connected at these scales remains a priority for bumblebee conservation.”
The research did produce one unique result – the rare species studied, Bombus ruderatus, had lower genetic diversity than the other species and nested at lower density. However, the research didn’t turn up evidence that reduced numbers had led to inbreeding in the rare species.
“Very little is known about how genetic factors may be affecting rare and declining bumblebees,” Dreier said. “The rare bumblebee species at our study site currently has a small population size. However, management actions in place seem to be preserving its remaining genetic diversity.”
The UK researchers noted that their country’s 24 indigenous bumblebee species are widespread, yet many populations of bees have declined over the past 50 years – the result of habitat loss and degradation. For most species, falling population numbers often lead to lower levels of genetic diversity, which raises their ability to cope with change and risk of extinction.
The research study was funded by the UK Insect Pollinators Initiative.