By Walter S. Sheppard, Thurber Professor of Apiculture
Recent declines in honey bee populations and increasing challenges to maintain colony health are of concern to both beekeepers and growers of crops needing pollination services. Amid widespread research on honey bee health issues, there remains a notable lack of research directed toward the genetic improvement of honey bees.
There is a strong queen production industry in the US, but queen producers rely primarily on populations of bees established during a major period of importation between 1860 and 1922 (when the Honey Bee Act restricted importation of bees). While importation of honey bee germplasm effectively ceased after 1922, feral European honey bee populations in some southern states served as supplementary sources of genetic variation for breeding operations. However, the arrival of parasitic Varroa mites in the US in 1987 led to a major decline in US feral honey bee populations. The genetic effect of “bottlenecks” associated with importation and parasite-driven population losses includes a reduction in the amount of honey bee genetic diversity available to queen breeders.
In 2012 we (BKH, SWC, WSS) traveled to Italy and made significant collections of A. m. ligustica semen from a number of apiaries in the central Piedmont and the Reggio-Emilia (Bologna) area. Honey bees of this subspecies constitute the basis of current US “Italian” honey bees, the most widely used honey bee strain for managed pollination and honey production in the US. Interestingly, the Bologna region represents the original Italian source location for the initial US importations of honey bees from Italy made in 1860.
Semen from all sample locations was collected for both fresh use and cryopreservation and returned to the US under a USDA-APHIS hand carry permit. Collaborating California queen producers had pre-shipped virgin queens from US domestic stocks to Pullman, WA and these were inseminated with imported fresh honey bee semen. Some of this semen was concurrently supplied to Dr. Judy Chen of the USDA-ARS Bee Research Laboratory in Beltsville MD for virus determination.
The objectives of our ongoing program to assist beekeepers to develop improved honey bees include:
- Continue collection of germplasm from endemic populations of European honey bees
- Cryopreservation of representative samples of all collected honey bee germplasm for long term breeding use.
- A selective breeding program to evaluate and improve introduced stocks and hybrids under US conditions, screening for resistance to pests and diseases
- Develop a Industry/University partnership to disseminate imported honey bee germplasm and assist in the evaluation and maintenance of desirable breeding stocks
The collection and re-introduction of genetic material from source populations of honey bee subspecies provides significant additional genetic resources for US bee breeders. Maintaining adequate genetic diversity in breeding stocks of bees is highly important as queen breeders strive to select for disease and parasite resistance in bee stocks and to reduce reliance on chemotherapeutic agents.