Advantages of Genetic Diversity in Mating Bees
Jennifer Martin, CSREES Staff (202) 720-8188
August 13, 2007
By Stacy Kish, CSREES Staff
Bees, unlike many insects, practice polyandry, when the queen mates with multiple, different males. This process promotes genetic diversity within the colony by decreasing intracolony relatedness. Understanding the advantages of polyandry in honey bee populations may lead to improved management of colonies and higher pollination efficiency for U.S. agriculture.
Heather Mattila and Tom Seeley at Cornell University in Ithaca, NY, conducted a study of honeybee swarms to determine if genetic diversity proved to be an advantage or disadvantage to a colony in establishing a new nest.
Honeybee populations swarm when starting a new colony. During the swarm, the queen and infertile adult females, called workers, relocate to a new area and begin construction of a new nest. Swarming is an energy and resource-depleting activity that stresses the entire honeybee population.
The scientists followed 21 swarms throughout the summer of 2006, of which 12 were genetically diverse and nine were genetically uniform. The development of colonies after swarming was compared by measuring comb construction, brood rearing, foraging activity, food storage, population size and weight gain.
Their work revealed that the productivity of the genetically diverse colonies far exceeded that of the uniform colonies in all categories evaluated. The higher production rates of the genetically diverse colonies early in the study enhanced the growth rates of the swarms later in the study. Production rates were determined by comb construction, food storage and foraging activity, while the growth rate was determined by brood rearing, population size and weight gain. These advantages of the genetically diverse population allowed colonies to more effectively survive the winter and produce swarms the following season.
The founding of a successful colony depends on efficient foragers that can quickly supply the colony with food reserves. The results from this study suggest the evolutionary practice of polyandry in honeybees is intimately linked to colony fitness.
This research is presented in the July 20 issue of the journal Science.
The USDA's Cooperative State Research, Education, and Extension Service (CSREES) funded this research project through the National Research Initiative (NRI) Entomology and Nematology program. The NRI is the largest peer reviewed, competitive grants program in CSREES. It supports research, education and extension grants that address key problems of national, regional and multi-state importance in sustaining all components of agriculture.
CSREES advances knowledge for agriculture, the environment, human health and well-being, and communities by supporting research, education and extension programs in the Land-Grant University System and other partner organizations. For more information, visit http://www.csrees.usda.gov.