Bee Science Symposium "Current Developments in Bee Research" ABSTRACTED PROCEEDINGS March 12, 1993 Cornwallis Room, Agricultural Centre, Kentville, Nova Scotia,Canada Sponsored by the Nova Scotia Beekeepers' Association and the Nova Scotia Department of Agriculture and Marketing with assistance from the Human Resource Development component of the Canada/Nova Scotia Agri-Food Development Agreement FORWARD On March 12, 1993 a unique symposium on current scientific research related to honeybees and their diseases and pests was held in the Cornwallis Room at the AgriculturalCentre, Kentville, N.S. The speakers at this symposium are recognized worldauthorities from the U.K., U.S., Alberta, Ontario and Nova Scotia. The topics coveredgenetic engineering, selective breeding, viral diseases and their transmission,honeybees as vectors of biological control agents, and pests of bumblebees.The following are abstracts of the presentations except in one case a summarytranscript is included. C O N T E N T S 1. Dr. Brenda V. Ball, Honey Bee Virus Infections Associated with Varroa jacobsoni Infestation. 2. Don Stoltz, Virologist, Development of Diagostic Tools for Virus Infection in the Honeybee. 3. John Phillips, Engineering a Gene for Insecticide Resistance in the Honeybee. 4. Thomas E. Rinderer, Breeding of Resistance to Varroa jacobsoni. 5. Dr. Don Nelson, Tracheal Mites Detection and Control Methods. 6. John C. Sutton, Use of Bees to Deliver Biocontrol Agents for Controlling Flower-Infecting Pathogens. 7. Richard M. Fisher, Bumble Bees: Parasites, Predators, Disease. 8. Summary List of Speakers, Addresses and Fax Numbers. 1. Honey Bee Virus Infections Associated with Varroa jacobsoni InfestationBrenda V. Ball, AFRC Institute of Arable Crops Research, Rothamsted ExperimentalStation, Harpenden, Herts. AL5 2JQ Fax: 0582 760981. ABSTRACT The parasitic mite Varroa jacobsoni causes little apparent damage in colonies of itsnatural host Apis cerana, the eastern hive bee. The transfer of the mite to theEuropean honey bee, Apis mellifera and its spread to every continent except Australasiahas been accompanied by reports of devastating colony losses, although the effects ofinfestation seem variable and are still poorly understood. Differences in thereproductive potential of mites on different species and races of bees and hostbehavioral responses may account for some of this variability. However, recentresearch has shown that the mite affects the type and prevalence of honey bee virusinfections causing mortality. This talk will consider the role of V. jacobsoni as anactivator and vector of honey bee viruses and examine some of the factors affectingdisease outbreaks in infested colonies. 2. Development of Diagostic Tools for Virus Infection in the HoneybeeDon Stoltz, Department of Microbiology & Immunology, Dalhousie University, Halifax,Nova scotia B3H 4H7 Fax: 902-494-5125. ABSTRACT My laboratory has been developing approaches to diagnostics which we think will proveuseful in the not-too-distant future. For example, in preliminary studies we havefound that virus infection in a single bee pupa can be readily detected by Westernblotting. Our primary focus thus far, however, has been directed towards an assessmentof polymerase chain reaction (PCR)-based technology for the detection of black queencell and Kashmir bee viruses. Use of PCR primers specific for conserved humanenterovirus sequences gave rise to several products; one of these, a 450 base pairamplicon from KBV has now been cloned and sequenced. Computer analysis indicate thatthis sequence comes from the viral RNA polymerase gene and shares significant homologywith the same gene found in a variety of known picornaviruses - including humanhepatitis A - and with many plant virus genomes as well. Future work will be directedtowards the development of both universal picornavirus primers and primers specificfor individual bee viruses. 3. Engineering a Gene f or Insecticide Resistance in the HoneybeeJohn Phillips, University of Guelph, Department of Molecular Biology and Genetics,Guelph, Ontario, Canada Fax: 519-837-2075. ABSTRACT We are applying current techniques of insect molecular biology to the design andintroduction of useful genes in beneficial insects. Such genes would include thoseencoding resistance to conventional insecticides. A potentially useful insecticideresistance gene, the `opd' gene, has been identified and cloned from bacteria. Thisgene specifies a unique phosphotriesterase which efficiently cleaves and detoxifiesa broad spectrum of organophosphorus insecticides. We have redesigned this gene tofunction in insects and have transferred it into the genome of the model insect,Drosophila melanogaster, where it functions to confer significant resistance toorganophosphate toxicity. This demonstrates the feasibility of conferring usefultraits on strains of insects through the design and introduction of carefully designedgenes. We are now refining the structure of the gene to target expression in specifictissues and developmental stages in order to enhance the efficacy of insecticideresistance. In addition, we have begun to develop techniques for transferring thisand/or other useful genes into the honeybee genome to confer useful and novel traitson the beneficial insect species. 4. Breeding for Resistance to Varroa jacobsoniThomas E. Rindere r, United States Department of Agriculture, Agricultural ResearchServices, Honey-Bee Breeding Genetics & Physiology research, Baton Rouge, Louisiana Fax: 504-389-0383. ABSTRACT A stock of honey bees was bred in Yugoslavia for resistance to the parasitic mite,Varroa jacobsoni. This stock was imported by the USDA to the US and extensively testedin field trials in Florida. These tests showed that the stock has some degree ofresistance to Varroa jacobsoni, a strong resistance to a second parasitic mite,Acarapis woodi, which is also a relatively new and economically troubling pest of honeybees in the US, and excellent general beekeeping characteristics. Based on theseresults, the Yugoslavian honey bee stock is scheduled to be released to industry nextspring. This release will be the first honey bee stock released from the USDA toindustry in decades. The general potential for developing honey bee stocks resistantto parasitic mites will be examined. Editor's Note:An excellent article by Rinderer, et al, in the March '93 issue of American BeeJournal, covers this subject in detail. 5. Tracheal Mites Detection and Control MethodsDr. Don Nelson, Agriculture Canada, Research Station, Beaverlodge, Alberta Fax: 403-354-8171 ABSTRACT Tracheal mites are becoming a common pest of honey bee colonies in most of Canada. Therefore, it is important to know when colonies are infested and at what levels. Atthe same time it is important to know at what levels tracheal mites are detrimentalto colonies, and how to control their buildup.The only method of detection at present is the dissection (and microscopic examination)of the thorax of individual bees. This method is time consuming and costly. TheBeaverlodge Research Station has developed a monoclonal antibody specific to thetracheal mite and is currently using and evaluating an ELISA (Enzyme-LinkedImmunosorbent Assay) method for detection of tracheal mites in bulk bee samples. Withfurther evaluation this method may become a preferred alternative to individual beeanalysis.Several approaches to reducing or minimizing the effect of tracheal mites are beingstudied; a) chemical control, b) management practices and c) selecting stock forresistance. The emphasis in the short term has certainly been to have one or moreregistered chemical controls available. Chemicals currently approved for use in Canadafor the control of tracheal mites are menthol and formic acid (by spring of 1993). For the short and mid-term, several management practices along with chemical controlsseem promising and for the long term selecting bees more resistant to the tracheal miteholds great promise. Ultimately, all three methods will be used in variouscombinations to provide the best results. 6. Use of Bees to Deliver Bioc ontrol Agents for Controlling Flower-Infecting PathogensJohn C. Sutton, Department of Environmental Biology, University of Guelph, Guelph,Ontario, Canada N1G 2W1 Fax: 519-837-0442 Honey bees (Apis mellifera) were found in recent studies to efficiently vector inoculumof microbial biocontrol agents to flowers of strawberry (Peng et al. 1992), raspberry(J.C. Sutton 1991, unpublished observations), apple and pear (Thompson et al. 1992). These observations were made a century after Waite (1891) reported for the first timethat honey bees vectored a pathogen, Erwinia amylovora, to flowers of pear trees. Foreffective biocontrol of flower-infecting pathogens, it is likely that intensivevectoring of biocontrol agents is required. To achieve adequate vectoring of agentsto flowers of crop plants, inoculum of the organisms must be suitably formulated toallow effective acquisition, transport, and deposition by bees.Bees successfully vectored spores of various biocontrol agents (eg. Gliocladium roseum,Epicoccum purpurascens, and Alternaria alternata) when formulated as powders with talc,pulverized corn meal, wheat flour, soya flour or corn starch (Peng et al. 1992, Israeland Boland 1992). The bacterial antagonists Pseudomonas fluorescens and Erwiniaherbicola were vectored to apple and pear flowers when absorbed to pollen of apple orcattail (Thomson et al. 1992). The bees were contaminated with the formulations inspecial inoculum dispensers or pollen inserts inside hives. Bees acquired inoculumon their legs and bodies and especially on the setae.In a biocontrol study of fruit rot of strawberry caused by Botrytis cinerea, bees eachacquired 88,000 - 1,800,000 (mean 570,000) cfu G. roseum in a talc formulation (5 x108 cfu/g) and maintained an inoculum density of 1,600 - 27,000 cfu of the antagoniston each flower (Peng et al. 1992). By comparison inoculum density in plots sprayedweekly with spore suspensions (107 conidia/mL) of G. roseum ranged from 300 to 15,000cfu/flower. Propagule density was more stable and often higher on flowers of the bee-vectored treatment than in spray-treated flowers, but the treatments were about equallyeffective in suppressing incidence of the pathogen on stamens and petals, and incontrolling fruit rot.Efficiency of inoculum deposition on flowers by bees probably depends on subtletiesin physical contact between the bee and the flower as well as the load and distributionof inoculum on the bee. Size and morphology of the flowers and of the bees, and theactivity and posturing of bees while on the flowers undoubtedly affect the amount ofinoculum deposited and where it is deposited on the flower. In studies at theUniversity of Guelph, bees delivered about 10 to 18 times more conidia of G. roseumper flower to strawberry than to raspberry. The formulation and concentration ofinoculum used was the same in all studies. While strawberry flowers are much largerthan raspberry flowers, and foraging frequencies by bees on the two types of lower mayhave differed, the bees also behaved differently on strawberry than on raspberry (J.C.Sutton, unpublished observations). In strawberry, bees tended to move actively overthe face of the flower, often in a rotational pattern, and their legs and bodiesfrequently contacted the stamens and other flower parts. In raspberry however, thebees moved only slightly and tended to cling to the elongate stamens by means of distalportions of their legs, and achieved only minor body contact with the flower. Whiledensity of vectored inoculum on raspberry was low, the antagonist nonethelesseffectively suppressed Botrytis fruit rot.Many variables influence the frequency of visits by bees to flowers and may thusinfluence vectoring of biocontrol agents and the effectiveness of biocontrol. Cooltemperature, wind and rain generally discourage foraging by bees (Free 1968 a,b),however in our studies in strawberry, bees vectored high densities of G. roseum to theflowers under a wide range of weather conditions (Peng et al. 1992). Foraging in testplots or in commercial crops can be affected by the proximity and attractiveness tobees of other kinds of flowers in the area that compete as sources of nectar and pollen(Levin 1978). For example, biocontrol of B. cinerea in strawberry by means of bee-vectored G. roseum soon became ineffective when the bees preferentially visited freshlyblooming rapeseed in nearby field plots (Peng et al. 1992). Chemical attractants canbe used in some instances to maintain foraging in the target crop.The mobility and foraging patterns of bees present special problems in field studies. Screens generally are needed to separate treatments with bees from those without bees,but may modify microclimate and exclude important pollinators. Bees confined in screencages may forage and vector differently from freely-ranging bees. Screening of alltreatments equalizes microclimatic modification but is impractical when plots or hostplants are large, and can be costly. Vectoring of biocontrol agents will requirespecial studies in commercial crops to determine the numbers, size and distributionof bee colonies needed for effective vectoring of microbial antagonists and forbiocontrol. In bee-vectoring studies in Utah, the antagonist Pseudomonas fluorescenswas detected on only 556% of apple flowers at 61 m from a hive, and on only 72% of pearflowers at 7 m from a hive, with an average population of 102 cfu per flower (Thomsonet al. 1992) - A stain of E. herbicola was detected on 92 - 96% of apple flowers ina 2.6 ha orchard (10-5700 cfu per flower). To encourage bees to establish foragingpatterns in a crop as opposed to other plants in the area, it is important to introducebee colonies shortly after the crop begins to flower.Various bees potentially could be used to vector microbial antagonists to many kindsof plant for biocontrol of various flower-infecting pathogens. Several kinds ofdomesticated bees, including bumble bees (Bombus spp.) and leaf cutting bees (Megachilespp., Osmia spp.) as well as honey bees, may have potential as vectors. Wild speciesof halictid bees and andrenid bees also possibly could be used, and contaminated withbiocontrol agents at bait stations. Various berry crops, orchard fruits, crucifercrops, beans, clovers, and cucurbits possibly could be protected by bee-vectoredantagonists. Imaginative research could lead to effective, efficient, andenvironmentally safe biocontrol of many crop diseases by means of bee-vectoredantagonists. Literature cited FREE, J.B., 1968. The pollination of strawberries by honey bees. J. Hortic. Sci. 43:107-111. FREE, J.B., 1968. The foraging behaviour of honey bees (Apis mellifera) and bumblebees(Bombus spp.) on blackcurrant (Rubus nigrum), raspberry (Rubus idaeus) and strawberry(Fragaria x ananassa) flowers. J. Appl. Ecol. 5: 157-168. ISRAEL, M., & BOLAND, G.J., 1992. Influence of formulation on efficacy of honey beesto transmit biological control for management of Sclerotinia sclerotiorum. Can. J.Plant Pathol. (Abstr.) (In press). LEVIN, D.A., 1978. Pollination behaviour and the breeding structure of plantpopulations. Pages 133 - 150 in A.J. Richards, ed., The pollination of Flowers byInsects. Academic Press, London. 213 pp. PENG. G., SUTTON, J.C. & KEVAN, P.G., 1992. Effectiveness of honey bees for applyingthe biocontrol agent Gliocladium roseum to strawberry flowers to suppress Botrytiscinerea. Can. J. Plant Pathol. 14: 117-129. THOMSON, S.V., hansen, D.R., FLINT, K.M. & VANDENBERG, J.D., 1992. The disseminationof bacteria antagonistic to Erwinia amylovora by honey bees. Plant Dis. 76: 1052-1056. WAITE, M.B., 1891. Results from recent investigations in pear blight. Am. Assoc. Adv.Sci. Proc. 40:315. 7. Bumble Bees: Parasites, Predator s, DiseaseRichard M. Fisher, Department of Biology, Acadia University, Wolfville, Nova Scotia,Canada Fax: 902-542-3466 ABSTRACT During the 1980's, advances in bumble bee domestication technology permitted the cost-effective use of these bees for greenhouse tomato pollination. At present, threespecies are used for this purpose (Europe and New Zealand: B. terrestris; eastern NorthAmerica: B. impatiens (Cr.); western North America; B. occidentalls (Grne). Threeprimary concerns have been associated with the intensive laboratory culture of thesespecies: 1) depopulation of bees in areas where queens are captured; 2) the impactof species introductions into new area; 3) the possible spread of disease,either amongBombus populations, or interspecifically between bumblebees and other bees, notablyApis mellifera. Data are presented which demonstrate the genus specificity of a numberof bumble bee pests and pathogens, including mites, the microsporidian Nosema bombi,and a number of social parasites. The possible propagation of diseases among culturedBombus species can be eliminated (or at least minimized) through proper managementpractices. 8. SPEAKERS Brenda V. BallAFRC Institue of Arable Crops ResearchRothamsted Experimental StationHarpenden, Herts AL5 2JQFax: 0582 760981 Don StoltzDepartment of Microbiology & ImmunologyDalhousie UniversityHalifax, Nova ScotiaB3H 4H7Fax: (902) 494-5125 John PhillipsUniversity of GuelphDepartment of Molecular Biology & GeneticsGuelph, OntarioN1G 2W1Fax: (519) 837-2075 Thomas E. RindererUnited States Department of AgricultureAgricultural Research Services, Mid South AreaHoney-Bee Breeding, Genetics & Physiology Research1157 Ben Hur RoadBaton Rouge, Louisiana 70820Fax: (504) 389-0383 Don NelsonAgriculture CanadaResearch StationBeaverlodge, AlbertaT0H 0C0Fax: (403) 354-8171 John C. SuttonDepartment of Environmental BiologyUniversity of GuelphGuelph, OntarioN1G 2W1Fax: (519) 837-0442 Richard M. FisherDepartment of BiologyAcadia UniversityWolfville, Nova scotiaB0P 1X0Fax: (902) 542-3466