2011 Annual Report
Controlling the key parasite Varroa destructor through genomics. Novel controls based on genomics will provide for strong control of parasitic mites while reducing the use of chemicals. A genome draft sequence was published for this mite, revealing potential weak points in mite biology (defensive proteins, and proteins used in chemical mitigation) and candidates for novel controls such as RNA interference (RNAi), a method for knocking down specific pest proteins. The description of mite candidate genes allowed the initiation worldwide of RNAi efforts for this parasite, ending in late 2010 with the first successful demonstration of RNAi activity in Varroa. Microbes identified in this screen have also been screened across bees and mites as plausible controls for Varroa. Companies producing products for bee health will use these results to expand the mite control tools available to beekeepers.
Tools development for tracking and understanding CCD. Efforts to improve bee health have suffered from an inability to accurately assess disease caused by viruses and other pathogens. BRL scientists improved current methods to collect field honey bees populations and ship for genetic analyses, stabilize and extract RNA, conduct high-throughput genetic screens for viruses and other pests, collect embryos from established colonies, and carry out controlled experiments on adult bees using sterile cups. These methods are being used in national surveys in the U.S. in order to establish cell lines and other genetic techniques, and to better determine interactive effects.
Nosema ceranae impacts. Controlled experiments documented interactions between Nosema parasites and other pathogens in causing CCD. While multifactorial analyses did not point to Nosema as an integral part of CCD, this parasite was confirmed as being present wherever CCD was found, and at higher levels than in past surveys. In addition, it became clear that Nosema ceranae has recently spread worldwide and is a permanent part of bee populations on all continents with beekeeping.
Insect Immunity. Honey bees combat American foulbrood, viruses, and Nosema with immunity proteins found across the insects. A BRL scientist determined immune gene protein variation across bees and ants, an essential step in determining which proteins are responsive to novel viruses, bacteria, and fungi. This information is being used in programs to test specific immune genes for breeding purposes.
Movement of the small hive beetle worldwide. Genetic analyses revealed the origins of two new populations of the small hive beetle, Aethina tumida, an important parasite of bees. This beetle has left subharan Africa at least twice (and likely three times), and continues to spread even to countries which do no accept bee importations form outside (e.g., Australia). Along with reducing impacts of this pest across the world, these results have immediate impact in trade decisions and regulations.
Causes and treatment for Colony Collapse Disorder. BRL scientists determined likely factors in CCD, including RNA viruses, chemical exposure, and the gut parasite Nosema ceranae. These efforts confirmed the view that CCD is a multifaceted problem, with both biological and abiotic causes, and that hive management offered one possible route for mitigating CCD. Understanding how biological causes like viruses interact with other bee threats will improve the ability of beekeepers to manage their bees.
Viljakainen, L., Evans, J.D., Hasslemann, M., Rueppel, O., Tingek, S., Pamilo, P. 2009. Rapid evolution of immune proteins in social insects. Molecular Biology and Evolution. 26:1791-1801.
Evans, J.D., Chen, Y., Diprisco, G., Pettis, J.S., Williams, V.P. 2009. Bee cups: Single-use cages for honey bee experiments. Journal of Apicultural Research. 48(4):300-302.
Frazier, M., Muli, E., Conklin, T., Schmehl, D., Torto, B., Frazier, J., Tumlinson, J., Evans, J.D., Raina, S. 2010. A Scientific note on Varroa mites found in East Africa; Threat or Opportunity. Apidologie. 41:463-465.
Lounsberry, Z.T., Spiewok, S., Pernal, S., Sonstegard, T.S., Hood, M.W., Pettis, J.S., Neumann, P., Evans, J.D. 2010. Chasing your honey: Worldwide diaspora of the small hive beetle, a parasite of honey bee colonies. Annals of the Entomological Society of America. 104:671-677.
Evans, J.D., Boncristiani Jr., H.F., Chen, Y. 2010. Scientific note on mass collection and hatching of honey bee embryos. Apidologie. 41:654-656.
Cornman, R.S., Schatz, M.C., Johnston, S.J., Chen, Y., Pettis, J.S., Hunt, G., Bourgeois, A.L., Elsik, C., Anderson, D., Grozinger, C.M., Evans, J.D. 2010. Genomic survey of the ectoparasitic mite Varroa destructor, a major pest of the honey bee Apis mellifera. Biomed Central (BMC) Genomics. 11:602.
Dainat, B., Evans, J.D., Chen, Y., Neumann, P. 2011. Sampling and RNA quality for successful diagnostics using quantitative PCR. Journal of Pest Science. 174:150-152.