Origin and Diversification of Honey Bees: Conservation Status and the Consequences of Colonization
Apis mellifera is a species within a genus that contains perhaps a dozen recognized species. Most of the species comprising Apis are endemic to eastern Asia, whereas the “western” honey bee, Apis mellifera, has a range that includes Europe, Africa and much of western/central Asia. Within this vast range, over two dozen “subspecies” are recognized. Human movement of bees and the recent effects of parasitic mites and pathogens have resulted in severe population losses within some of these Old World subspecies leading, in some cases, to concerted efforts to conserve honey bee germplasm and habitat.
A number of subspecies were introduced into North America during European expansion and form the basis for the honey bee populations currently maintained by US beekeepers. However, only about a third of the described subspecies of A. mellifera, were introduced into North America. Of these, only three subspecies found “favor” with US beekeepers and were maintained in some manner to be subsequently sold as strains or varieties (Italian, Carniolan, and Caucasian). Furthermore, the concept of “grafting” daughters from selected colonies (introduced in the late 1880’s) led to the development of our modern queen production industry, where hundreds of thousands of daughter queens are produced from a relatively small pool of queen mothers. In 1922, the passage of the US Honey Bee Act restricted further importation of honey bees and this restriction continues today
The manner in which bees were initially sampled and introduced to North America, the methods by which production queens are produced annually from a small pool of mothers and increased annual colony losses that resulted from parasitic mites and diseases all represent “genetic bottlenecks” that have impinged on US honey bee populations. The importation and distribution of Old World honey bee germplasm to US beekeepers serves to provide additional “raw material” for bee breeding purposes. The use of cryopreservation of honey bee germplasm is in its infancy, but already has had an impact on both bee breeding and honey bee conservation programs.
Banquet Presentation: Ongoing WSU Projects in Colony Health Research and Honey Bee Breeding
At present, the WSU honey bee program personnel includes 2.5 faculty members with research, extension, and teaching responsibilities, 2 PhD postdoctoral researchers, and 6 graduate students (5 MSc and 1 PhD). There are a number of research and outreach projects underway within the program, in addition to an ongoing long-term honey bee breeding effort. These projects include:
1) Efforts to address honey bee colony health concerns (mites and viruses) with mycologically based approaches. This includes biological control of mites using a strain of Metaryzium selected for virulence (against mites) and for improved thermotolerance. We are also involved in research and development to reduce the impacts of viruses in bees through improved immune function by feeding polypore mushroom extracts. In addition, the team is evaluating potential effects of these mushroom extracts on Nosema and foulbrood.
2) Indoor storage of colonies and manipulation of metabolic gases in controlled atmosphere storage to address colony health. Research on best practices to improve both overwintering and support of summer bee populations using indoor storage are underway.
3) Importation, cryopreservation, and distribution of Old World honey bee genetic diversity. The rationale for this work is two-fold: WSU is assisting bee breeding efforts of queen producers in the US by providing producers with i.i. breeder queens of novel stocks (such as Caucasian honey bees). The WSU honey bee germplasm repository contains genetic material (frozen sperm) from a number of Old World subspecies, including those for which there are conservation concerns.
4) WSU also maintains a line of honey bees (WSU Program Bees) that has been under continual selection for apicultural traits in the Pacific Northwest for 19 years. These bees are maintained without antibiotics and have been used for commercial almond pollination in California for the past 5 years.
5) Use of RFID technology to evaluate foraging and mating behavior in honey bees. Two ongoing MSc projects are using this technology.
6) Honey bee reproductive biology, including discovery research to improve our current methods of cryopreservation and cooperative establishment of an international network of germplasm repositories.
7) In addition to annual queen rearing and beekeeping workshops, we are also developing an updated video about instrumental insemination and bee breeding, with the goal to make these techniques more assessable to beekeepers interested in queen breeding and production.
Steve Sheppard is the Thurber Professor of Apiculture in the Department of Entomology at Washington State University, Pullman, Washington. His graduate research at the University of Illinois centered on population genetics and evolution in honey bees. Prior to joining the faculty at WSU, Steve worked as a research scientist for the US Department of Agriculture, conducting research on Africanized honey bees and the genetic processes that accompany insect range expansions.
In addition to ongoing research on genetics and evolution, the WSU Bee Program conducts research on insect introductions, basic mechanisms of genetic differentiation and on honey bee colony health. Steve, his graduate students, postdoctoral researchers and colleagues select and breed honey bees for Pacific Northwest conditions. The Program also provides inseminated breeder queens to queen producers, an effort that has increased genetic variability within these commercial sources of queens. Since 2008, the bee research program at WSU has actively imported germplasm of several honey bee subspecies of apicultural interest. By developing practical cryopreservation methods, WSU was able to establish the world’s first honey bee germplasm repository for the conservation of Old World honey bee germplasm and for the preservation of current top-tier selected bee stocks from US queen producers. The laboratory has a number of projects on honey bee colony health, including the sub-lethal effects of pesticide exposure and the effects of metabolic gases on indoor storage of colonies
In collaboration with mycologists at Fungi Perfecti, the WSU Bee Program is involved in a major research effort to use fungi as a biological control agent for parasitic mites and to use polypore mushroom extracts to improve the health of honey bees. We have partnered with interested commercial beekeepers to conduct large-scale field experiments involving hundreds of honey bee colonies. A recent publication by the Bee team demonstrated that bees fed with mycelial extracts of several polypore mushroom species exhibited a significant reduction in virus titers, compared to control bees fed sugar syrup alone.