Survival of honey bee (Hymenoptera: Apidae) spermatozoa stored at above-freezing temperatures

The development of practical techniques for the storage of honey bee, Apis mellifera L., semen would significantly improve our ability to breed for desirable genotypes and maintain genetic diversity in populations. Artificial insemination of queens has been possible for some time, but the semen used is usually freshly collected, or held for < 1 wk at room temperature. I examined the limitations of spermatozoal survival at nonfrozen temperatures. Pooled, diluted semen was stored in sealed capillary tubes at room temperature (25 degrees C) or in a refrigerator set to 12 degrees C, for periods up to 1 yr. Survival of spermatozoa was assayed by a dual fluorescent staining technique using SYBR-14 and propidium iodide stains, which readily distinguishes live and dead cells. No significant loss of viable spermatozoa occurred within the first 6 wk. Between weeks 6 and 9, the percent live spermatozoa fell from 80 to 58%, and remained at that level until after 39 wk. By week 52, samples at room temperature, but not at 12 degrees C, fell to 18.9% live spermatozoa. Nonfrozen storage of honey bee semen has potential for short-term preservation of germplasm, however several factors need to be studied further to optimize survival rates.     

Variation in worker response to honey bee (Apis mellifera L.) queen mandibular pheromone (Hymenoptera: Apidae)

Genetic and environmental influences on the worker honey bee retinue response to queen mandibular gland pheromone (QMP) were investigated. Worker progeny were reared from queens originating from four sources: Australia, New Zealand, and two locations in British Columbia, Canada (Simon Fraser University and Vancouver Island). Progeny from New Zealand queens responded significantly higher (P < 0.05) than progeny from Australia in a QMP retinue bioassay. Retinue response was not related to queen production of pheromone or colony environment, and the strain-dependent differences in retinue bioassay responses were maintained over a wide range of dosages. Selected high- and low-responding colonies were bioassayed over the course of 1 year. High-responding colonies contacted QMP lures more frequently than low-responding colonies (P < 0.05) throughout the year except in late summer. We conclude that there is a strong genetic component to QMP response by worker honey bees, as well as a seasonal effect on response.     

Live Varroa jacobsoni (Mesostigmata: Varroidae) fallen from honey bee (Hymenoptera: Apidae) colonies

The proportion of Varroa jacobsoni Oudemans that were alive and mobile when they fell from honey bees, Apis mellifera L., in hives was measured during a 20-wk period to determine the potential use of systems that prevent these mites from returning to the bees. Traps designed to discriminate between the live, fallen mites and those that are dead or immobile were used on hive bottom boards. A large fraction of the fallen mites was alive when acaricide was not in use and also when fluvalinate or coumaphos treatments were in the hives. The live proportion of mitefall increased during very hot weather. The proportion of mitefall that was alive was higher at the rear and sides of the hive compared with that falling from center frames near the hive entrance. More sclerotized than callow mites were alive when they fell. A screen-covered trap that covers the entire hive bottom board requires a sticky barrier to retain all live mites. This trap or another method that prevents fallen, viable mites from returning to the hive is recommended as a part of an integrated control program. It also may slow the development of acaricide resistance in V. jacobsoni and allow the substitution of less hazardous chemicals for the acaricides currently in use.     

Compatibility of an organically based insect control program with honey bee (Hymenoptera: Apidae) pollination in cantaloupes

The application of azadirachtin to foliage of cantaloupes did not significantly reduce successful pollination by commercially managed honey bees, Apis mellifera L., as measured by numbers of foraging honey bees and yield. Similar results were obtained when the synthetic insecticide imidacloprid (used as a standard by cantaloupe growers) was applied to the soil. Fruit yield and quality, as a function of bee pollination, were statistically equal between the two treatments, and equal to that of the untreated control. The standard treatment of imidacloprid gave significantly better control than azadirachtin of one pest (cucumber beetle) early in the season. Fruit maturity was delayed in untreated plots, consistent with light insect pressure observed. These results indicate that an organically based insect control approach will not alter bloom acceptance and bee forager activity in cantaloupes.     

Influence of honey bee (Hymenoptera: Apidae) density on the production of canola (Crucifera: Brassicacae)

Pollination is an essential step in the seed production of canola, Brassica napus L. It is achieved with the assistance of various pollen vectors, but particularly by the honey bee, Apis mellifera L. Although the importance of pollination has been shown for the production of seed crops, the need to introduce bee hives in canola fields during flowering to increase oil seed yield has not yet been proven. With the purpose of showing this, hives of A. mellifera were grouped and placed in various canola fields in the Chaudière-Appalaches and Capitale-Nationale regions (nine fields; three blocks with three treatments; 0, 1.5, and 3 hives per hectare). A cage was used to exclude pollinators and bee visitations were observed in each field. After the harvest, yield analyses were done in relation to the bee density gradient created, by using pod set, number of seeds per plant, and weight of 1000 seeds. Results showed an improvement in seed yield of 46% in the presence of three honey bee hives per hectare, compared with the absence of hives. The introduction of honey bees contributed to production and consequently, these pollinators represented a beneficial and important pollen vector for the optimal yield of canola.     

Varroa destructor infestation in untreated honey bee (Hymenoptera: Apidae) colonies selected for hygienic behavior

Honey bee (Apis mellifera L.) colonies bred for hygienic behavior were tested in a large field trial to determine if they were able to resist the parasitic mite Varroa destructor better than unselected colonies of"Starline" stock. Colonies bred for hygienic behavior are able to detect, uncap, and remove experimentally infested brood from the nest, although the extent to which the behavior actually reduces the overall mite-load in untreated, naturally infested colonies needed further verification. The results indicate that hygienic colonies with queens mated naturally to unselected drones had significantly fewer mites on adult bees and within worker brood cells than Starline colonies for up to 1 yr without treatment in a commercial, migratory beekeeping operation. Hygienic colonies actively defended themselves against the mites when mite levels were relatively low. At high mite infestations (>15% of worker brood and of adult bees), the majority of hygienic colonies required treatment to prevent collapse. Overall, the hygienic colonies had similar adult populations and brood areas, produced as much honey, and had less brood disease than the Starline colonies. Thus, honey bees bred for hygienic behavior performed as well if not better than other commercial lines of bees and maintained lower mite loads for up to one year without treatment.     

Influence of pollen diet in spring on development of honey bee (Hymenoptera: Apidae) colonies

The effects of changes in spring pollen diet on the development of honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies were examined in a 3-yr study (2002-2004). Pollen-supplemented and pollen-limited conditions were created in colonies every spring, and brood rearing and honey yields were subsequently monitored throughout the summer. In all 3 yr, colonies that were supplemented with pollen or a pollen substitute in the spring started rearing brood earlier than colonies in other treatment groups and produced the most workers by late April or early May. In 2002, these initial differences were reflected by a two-fold increase in annual honey yields by September for colonies that were pollen-supplemented during the spring compared with pollen-limited colonies. In 2003 and 2004, differences between treatment groups in the cumulative number of workers produced by colonies disappeared by midsummer, and all colonies had similar annual honey yields (exception: in one year, productivity was low for colonies supplemented with pollen before wintering). Discrepancies between years coincided with differences in spring weather conditions. Colonies supplemented with pollen or a substitute during the spring performed similarly in all respects. These results indicate that an investment in supplementing the pollen diet of colonies would be returned for situations in which large spring populations are important, but long-term improvement in honey yields may only result when spring foraging is severely reduced by inclement weather. Beekeepers should weigh this information against the nutritional deficiencies that are frequently generated in colonies by the stresses of commercial management.     

Frugivory by a stingless bee (Hymenoptera: Apidae)

Frugivory is not frequent among bees. Although stingless bees visit aged fruits for pulp, the use of fresh fruits is recorded only for Trigona hypogea Silvestri, a species that does not visit flowers. Here we report the occurrence of frugivory in Trigona amazonensis (Ducke), a flower-visiting stingless bee.     

Potential of ozone as a fumigant to control pests in honey bee (Hymenoptera: Apidae) hives

Ozone is a powerful oxidant capable of killing insects and microorganisms, and eliminating odors, taste, and color. Thus, it could be useful as a fumigant to decontaminate honey comb between uses. The experiments here are intended to determine the exposure levels required to kill an insect pest and spore forming bee pathogens. Ozone was effective against greater wax moth, Galleria mellonella (L.) (Lepidoptera: Pyralidae), even on naturally infested comb. Neonates and adults were the easiest life stages to kill, requiring only a few hours of exposure, whereas eggs required a 48-h exposure (at 460-920 mg O3/m3). Two honey bee, Apis mellifera L. (Hymenoptera: Apidae), pathogens, Ascosphaera apis (a fungus that causes chalkbrood) and Paenibacillus larvae (a bacterium that causes American foulbrood), also were killed with ozone. These pathogens required much higher concentrations (3200 and 8560 mg O3/m3, respectively) and longer exposure periods (3 d) than needed to control the insects. P. larvae was effectively sterilized only when these conditions were combined with high temperature (50 degrees C) and humidity (> or =75% RH). Thus, ozone shows potential as a fumigant for bee nesting materials, but further research is needed to evaluate its acceptability and efficacy in the field. The need for a reliable method to decontaminate honey bee nesting materials as part of an overall bee health management system is discussed.     

Russian honey bee (Hymenoptera: Apidae) colonies: Acarapis woodi (Acari: Tarsonemidae) infestations and overwintering survival

Honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies infested by parasitic mites are more prone to suffer from a variety of stresses, including cold temperature. We evaluated the overwintering ability of candidate breeder lines of Russian honey bees, most of which are resistant to both Varroa destructor Anderson & Trueman and Acarapis woodi (Rennie), during 1999-2001. Our results indicate that Russian honey bee colonies (headed by original and supersedure queens) can successfully overwinter in the north, even during adverse weather conditions, owing to their frugal use of food stores and their resistance to tracheal mite infestations. In contrast, colonies of Italian honey bees consumed more food, had more mites, and lost more adult bees than Russian honey bees, even during unusually mild winter conditions.     

The vibration dance behavior of queenless workers of the honey bee,Apis mellifera (Hymenoptera: Apidae)

The vibration dance was investigated in queenless (QL) colonies of honey bees. Workers performing the dance had significantly less-developed ovaries than recipients. Vibrators were more likely to be mauled by nestmates (an aggressive act) and were more strongly associated with foraging than were nonvibrating controls. Recipients responded to the dance by increasing the amount of time spent performing tasks. The vibration dance may therefore be associated with aggression in QL colonies and may give workers with less-developed ovaries a degree of control over the behavior of bees with greater ovarian development.     

American foulbrood and African honey bees (Hymenoptera: Apidae)

We have taken samples of honey from individual beekeepers (N = 64), and of domestic (N = 35) and imported honey (N = 15) retailed in supermarkets in several sub-Saharan countries and cultivated these samples for Paenibacillus larvae subsp. larvae Heyndrickx et al. causing American foulbrood in honey bee colonies. The results are compared with samples of similar backgrounds and treated the same way but collected in Sweden (N = 35). No P. larvae subsp. larvae spores were found in any honey produced in Africa south of the Sahara although honey imported into this region frequently contains the pathogen. Swedish honey frequently contains P. larvae subsp. larvae spores although the general level of visibly infected bee colonies is low (roughly 0.5%). The results suggest that large parts of Africa may be free from American foulbrood. Behavioral studies (hygienic behavior) on Apis mellifera subsp. scutellata Lepeletier in Zimbabwe suggest that hygienic behavior of African bees could influence the apparent low level, or even absence of American foulbrood in large parts of Africa.     

Treatment with synthetic brood pheromone (SuperBoost) enhances honey production and improves overwintering survival of package honey bee (Hymenoptera: Apidae) colonies

We evaluated a year-long treatment regime testing synthetic, 10-component, honey bee, Apis mellifera L. (Hymenoptera: Apidae), brood pheromone (SuperBoost; Contech Enterprises Inc., Delta, BC, Canada) on the productivity and vigor of package bee colonies in the lower Fraser Valley of British Columbia, Canada. Fifty-eight newlyestablished 1.3-kg (3-lb) colonies treated three times with SuperBoost at 5-wk intervals starting 30 April 2009 were compared with 52 untreated control colonies. Treated colonies produced 84.3% more honey than untreated control colonies. By 8 September 2009, SuperBoost-treated colonies had 35.4% more adults than untreated colonies. By 28 September, net survival of treated and control colonies was 72.4 and 67.3%, respectively. On 5 October, treated and control colonies were divided into two additional groups, making up four cohorts: SuperBoost-treated colonies treated again during fall and spring build-up feeding with pollen substitute diet (BeePro, Mann Lake Ltd., Hackensack, MN; TIT); controls that remained untreated throughout the year (CCC); colonies treated with SuperBoost in spring-summer 2009 but not treated thereafter (TCC); and original control colonies treated with SuperBoost during the fall and spring build-up feeding periods (CTT). There was no difference among cohorts in consumption of BeePro during fall feeding, but TTT colonies (including daughter colonies split off from parent colonies) consumed 50.8% more diet than CCC colonies during spring build-up feeding. By 21 April, the normalized percentages of the original number of colonies remaining (dead colonies partially offset by splits) were as follows: CCC, 31.4%; CTT, 43.8%; TCC, 53.59%; and TTT, 80.0%. The net benefit of placing 100 newly established package bee colonies on a year-long six-treatment regime with SuperBoost would be US$6,202 (US$62.02 per colony). We conclude that treatment with SuperBoost enhanced the productivity and survival of package bee colonies and hypothesize that similar results could be achieved with established colonies.     

csd alleles in the red dwarf honey bee (Apis florea,Hymenoptera: Apidae) show exceptionally high nucleotide diversity

Abstract The single locus complementary sex determination (sl‐csd) gene is the primary gene determining the gender of honey bees (Apis spp.). While the csd gene has been well studied in the Western honey bee (Apis mellifera), and comparable data exist in both the Eastern honey bee (Apis cerana) and the giant honey bee (Apis dorsata), no studies have been conducted in the red dwarf honey bee, Apis florea. In this study we cloned the genomic region 3 of the A. florea csd gene from 60 workers, and identified 12 csd alleles. Analysis showed that similar to A. mellifera, region 3 of the csd gene contains a RS domain at the N terminal, a proline‐rich domain at the C terminal, and a hypervariable region in the middle. However, the A. florea csd gene possessed a much higher level of nucleotide diversity, compared to A. mellifera, A. cerana and Apis dorsata. We also show that similar to the other three Apis species, in A. florea, nonsynonymous mutations in the csd gene are selectively favored in young alleles.     

Honey bee (Hymenoptera: Apidae) foraging in response to preconditioning with onion flower scent compounds

Onion (Allium cepa L.) seed production has long been plagued with yield problems because of lack of pollination by the honey bee, Apis mellifera L. To attempt to attract more pollinators to the onion seed production field, honey bees were conditioned to associate onion floral odor components with a reward. Isolated nucleus hives of honey bees were fed 30% sucrose solutions scented with a 0.2% solution of onion floral odor compounds. After feeding on these solutions for 6 wk, bees were not found to prefer onion flowers to two competing food sources, carrot and alfalfa flowers, at the 5% significance level. However, there was an overall trend indicating a change in honey bee behavior, with fewer "trained" bees visiting alfalfa and carrot and more visiting onion. Thus, it may be possible to alter honey bee behavior with preconditioning but probably not to a degree that would be economically significant.     

Managing honey bees (Hymenoptera: Apidae) for greenhouse tomato pollination

Although commercially reared colonies of bumble bees (Bombus sp.) are the primary pollinator world-wide for greenhouse tomatoes (Lycopersicon esculentum Mill.) previous research indicates that honey bees (Apis mellifera L.) might be a feasible alternative or supplement to bumble bee pollination. However, management methods for honey bee greenhouse tomato pollination scarcely have been explored. We 1) tested the effect of initial amounts of brood on colony population size and flight activity in screened greenhouses during the winter, and 2) compared foraging from colonies with brood used within screened and unscreened greenhouses during the summer. Brood rearing was maintained at low levels in both brood and no-brood colonies after 21 d during the winter, and emerging honey bees from both treatments had significantly lower weights than bees from outdoor colonies. Honey bee flight activity throughout the day and over the 21 d in the greenhouse was not influenced by initial brood level. In our summer experiment, brood production in screened greenhouses neared zero after 21 d but higher levels of brood were reared in unscreened greenhouses with access to outside forage. Flower visitation measured throughout the day and over the 21 d the colonies were in the greenhouse was not influenced by screening treatment. An economic analysis indicated that managing honey bees for greenhouse tomato pollination would be financially viable for both beekeepers and growers. We conclude that honey bees can be successfully managed for greenhouse tomato pollination in both screened and unscreened greenhouses if the foraging force is maintained by replacing colonies every 3 wk.     

Microsatellite loci for the stingless bee Melipona rufiventris (Hymenoptera: Apidae)

Eight microsatellite primers were developed from ISSR (intersimple sequence repeats) markers for the stingless bee Melipona rufiventris. These primers were tested in 20 M. rufiventris workers, representing a single population from Minas Gerais state. The number of alleles per locus ranged from 2 to 5 (mean = 2.63) and the observed and expected heterozygosity values ranged from 0.00 to 0.44 (mean = 0.20) and from 0.05 to 0.68 (mean = 0.31), respectively. Several loci were also polymorphic in M. quadrifasciata, M. bicolor, M. mandacaia and Partamona helleri and should prove useful in population studies of other stingless bees.