Are honey bees' foraging preferences affected by pollen amino acid composition?

Abstract.  1. Although pollen is a vital nutritional resource for honey bees, Apis mellifera , the influence of pollen quality on their foraging behaviour is little understood.
2. In choice-test experiments, bees showed no innate pollen-foraging preferences, but preferred oilseed rape Brassica napus pollen over field bean Vicia faba pollen after previous foraging experience of oilseed rape.
3. The free amino acid content of oilseed rape and field bean pollen was compared using high-performance liquid chromatography. Oilseed rape pollen contained a greater proportion of the most essential amino acids required by honey bees (valine, leucine, and isoleucine) than field bean, suggesting that oilseed rape pollen is of greater nutritional quality for honey bees than is field bean pollen.
4. Honey bee foraging preferences appeared to reflect pollen quality. The hypothesis that pollen amino acid composition affects the foraging behaviour of honey bees is discussed.     

Africanized honey bees (Hymenoptera: Apidae) have a greater fidelity to sunflowers than European bees

A study of sunflower, Helianthus annuus L., pollen collection by Africanized and European honey bees, Apis mellifera L., was conducted in a hybrid seed production field in Argentina. Africanized honey bees collected significantly larger proportions of sunflower pollen than did European honey bees. The result suggests that Africanized bees would be more efficient for commercial sunflower seed production.     

Effects of brood pheromone (SuperBoost) on consumption of protein supplement and growth of honey bee (Hymenoptera: Apidae) colonies during fall in a northern temperate climate

Honey bee, Apis mellifera L. (Hymenoptera: Apidae), nutrition is vital for colony growth and maintenance of a robust immune system. Brood rearing in honey bee colonies is highly dependent on protein availability. Beekeepers in general provide protein supplement to colonies during periods of pollen dearth. Honey bee brood pheromone is a blend of methyl and ethyl fatty acid esters extractable from cuticle of honey bee larvae that communicates the presence of larvae in a colony. Honey bee brood pheromone has been shown to increase protein supplement consumption and growth of honey bee colonies in a subtropical winter climate. Here, we tested the hypothesis that synthetic brood pheromone (SuperBoost) has the potential to increase protein supplement consumption during fall in a temperate climate and thus increase colony growth. The experiments were conducted in two locations in Oregon during September and October 2009. In both the experiments, colonies receiving brood pheromone treatment consumed significantly higher protein supplement and had greater brood area and adult bees than controls. Results from this study suggest that synthetic brood pheromone may be used to stimulate honey bee colony growth by stimulating protein supplement consumption during fall in a northern temperate climate, when majority of the beekeepers feed protein supplement to their colonies.     

Detection of Deformed wing virus, a honey bee viral pathogen, in bumble bees (Bombus terrestris and Bombus pascuorum) with wing deformities

Honey bees (Apis mellifera) productively infected with Deformed wing virus (DWV) through Varroa destructor (V. destructor) during pupal stages develop into adults showing wing and other morphological deformities. Here, we report for the first time the occurrence of bumble bees (Bombus terrestris, Bombus pascuorum) exhibiting wing deformities resembling those seen in clinically DWV-infected honey bees. Using specific RT-PCR protocols for the detection of DWV followed by sequencing of the PCR products we could demonstrate that the bumble bees were indeed infected with DWV. Since such deformed bumble bees are not viable DWV infection may pose a serious threat to bumble bee populations.     

Comparative analysis of thermoregulation in the nests of certain species of social insects

Studies have been made on thermal regulation in the nests of families of the honey bee Apis mellifera, wasp Dolihovespula silvestris and bumblebees Bombus terrestris, B. agrorum and B. lapidaris during their maximum development. It was shown that thermoregulation significantly stimulated the brood in the nest. Among the species investigated, the highest thermoregulatory capacities are exhibited by honey bees, this fact being associated with the large number of individuals in their colonies. During cooling, bees group around the brood and their bodies make a cover of thermal insulation. Sheltering of the nests plays the main role in heat preservation of wasps and bumblebees. The latter, using contact method of heating of cells with the brood, provide rather constant temperature for its development. Honey bees, wasps and bumblebees react to overheating in the nests essentially in a similar way, i. e. by active aeration of their nests by vigorous wing beatings. The frequency of beatings increases with the increase in temperature.     

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.     

Nosema ceranae is a long-present and wide-spread microsporidian infection of the European honey bee (Apis mellifera) in the United States

Honey bee samples collected between 1995 and 2007 from 12 states were examined for the presence of Nosema infections. Our results showed that Nosema ceranae is a wide-spread infection of the European honey bee, Apis mellifera in the United States. The discovery of N. ceranae in bees collected a decade ago indicates that N. ceranae was transferred from its original host, Apis cerana to A. mellifera earlier than previously recognized. The spread of N. ceranae infection in A. mellifera warrants further epidemiological studies to identify conditions that resulted in such a widespread infection.     

Olfactory conditioning of the proboscis extension in bumble bees

The foraging behaviour of bumble bees is well documented for nectar and/or pollen gathering, but little is known about the learning processes underlying such behaviour. We report olfactory conditioning in worker bumble bees Bombus terrestris L. (Hymenoptera: Apidae) obtained under laboratory conditions on restrained individuals. The protocol was adapted from the proboscis extension conditioning previously described in the honey bee Apis mellifera L. Bumble bees were found to be able to learn a pure odorant when it was presented in paired association with a sugar reward, but not when odour and reward were presented in an explicitly unpaired procedure. This suggests an associative basis for this olfactory learning. Bumble bees showed similar conditioning abilities when stimulated with two different floral odours. An effect of the sugar reward concentration on the learning performances was found.     

Racial Differences in Division of Labor in Colonies of the Honey Bee (Apis mellifera)

We measured the age at onset of foraging in colonies derived from three races of European honey bees, Apis mellifera mellifera, Apis mellifera caucasica and Apis mellifera ligustica , using a cross-fostering design that involved six unrelated colonies of each race. There was a significant effect of the race of the introduced bees on the age at onset of foraging: cohorts of A. m. ligustica bees showed the earliest onset, regardless of the race of the colony they were introduced to. There also was a significant effect of the race of the host colony: cohorts of bees introduced into mellifera colonies showed the earliest onset of foraging, regardless of the race of the bees introduced. Significant inter-trial differences also were detected, primarily because of a later onset of foraging in trials conducted during the autumn (September–October). These results demonstrate differences among European races of honey bees in one important component of colony division of labor. They also provide a starting point for analyses of the evolution of division of labor under different ecological conditions.     

Nectar robbery by bees Xylocopa virginica and Apis mellifera contributes to the pollination of rabbiteye blueberry

Honey bees, Apis mellifera L., probe for nectar from robbery slits previously made by male carpenter bees, Xylocopa virginica (L.), at the flowers of rabbiteye blueberry, Vaccinium ashei Reade. This relationship between primary nectar robbers (carpenter bees) and secondary nectar thieves (honey bees) is poorly understood but seemingly unfavorable for V. ashei pollination. We designed two studies to measure the impact of nectar robbers on V. ashei pollination. First, counting the amount of pollen on stigmas (stigmatic pollen loading) showed that nectar robbers delivered fewer blueberry tetrads per stigma after single floral visits than did our benchmark pollinator, the southeastern blueberry bee, Habropoda laboriosa (F.), a recognized effective pollinator of blueberries. Increasing numbers of floral visits by carpenter bee and honey bee robbers yielded larger stigmatic loads. As few as three robbery visits were equivalent to one legitimate visit by a pollen-collecting H. laboriosa female. More than three robbery visits per flower slightly depressed stigmatic pollen loads. In our second study, a survey of 10 commercial blueberry farms demonstrated that corolla slitting by carpenter bees (i.e., robbery) has no appreciable affect on overall V. ashei fruit set. Our observations demonstrate male carpenter bees are benign or even potentially beneficial floral visitors of V ashei. Their robbery of blueberry flowers in the southeast may attract more honey bee pollinators to the crop.     

Honey bee (Hymenoptera: Apidae) distribution and potential for supplementary pollination in commercial tomato greenhouses during winter

This study examined the use of honey bees, Apis mellifera L., to supplement bumble bee, Bombus spp., pollination in commercial tomato, Lycopersicon esculentum Miller, greenhouses in Western Canada. Honey bee colonies were brought into greenhouses already containing bumble bees and left for 1 wk to acclimatize. The following week, counts of honey and bumble bees foraging and flying throughout the greenhouse were conducted three times per day, and tomato flowers open during honey bee pollination were marked for later fruit harvest. The same counts and flower-marking also were done before and after the presence of honey bees to determine the background level of bumble bee pollination. Overall, tomato size was not affected by the addition of honey bees, but in one greenhouse significantly larger tomatoes were produced with honey bees present compared with bumble bees alone. In that greenhouse, honey bee foraging was greater than in the other greenhouses. Honey bees generally foraged within 100 m of their colony in all greenhouses. Our study invites further research to examine the use of honey bees with reduced levels of bumble bees, or as sole pollinators of greenhouse tomatoes. We also make specific recommendations for how honey bees can best be managed in greenhouses.     

Cross-species infection of deformed wing virus poses a new threat to pollinator conservation

The Deformed wing virus (family Iflaviridae, genus Iflavirus, DWV), one of the most prevalent and common viruses in honey bees, Apis mellifera L., is present in both laboratory-reared and wild populations of bumble bees, Bombus huntii Greene. Our studies showed that DWV infection spreads throughout the entire body of B. huntii and that the concentration of DWV is higher in workers than in males both collected in the field and reared in the laboratory, implying a possible association between the virus infection and foraging activities. Further results showed that gut tissue of B. huntii can support the replication of DWV, suggesting that B. huntii is a biological host for DWV, as are honey bees. Bumble bees and honey bees sometimes share nectar and pollen resources in the same field. The geographical proximity of two host species probably plays an important role in host range breadth of the virus.     

Could learning of pollen odours by honey bees (Apis mellifera) play a role in their foraging behaviour?

Abstract. The role of pollen odour cues in the foraging behaviour of honey bees (Apis mellifera L.) is poorly understood. Using classical conditioning of the proboscis extension response, in which bees learn to associate an odour with a sucrose reward, the present study tests whether odours of bee-collected pollen from the hive environment or odours of fresh pollen on the anthers of flowers could be used in pollen foraging. Honey bees efficiently learn odours from field-bean (Vicia faba) bee-collected pollen and oilseed-rape (Brassica napus) bee-collected pollen, hand-collected pollen, anthers and whole flowers, demonstrating that honey bees can learn pollen odours associatively in biologically realistic concentrations. Honey bees learn pollen odours of oilseed rape better than field bean and, although they generalize these two odours, they easily distinguish between them in discrimination tests, suggesting that pollen odours may be used in species recognition/discrimination. There is little evidence that honey bees can recognize whole flowers based on previous experience of bee-collected pollen odour. However, they generalize the odours of oilseed-rape anthers and whole flowers, suggesting that anther pollen in situ may play a more prominent role than bee-collected pollen in foraging behaviour.     

Invasive Africanized honey bee impact on native solitary bees: a pollen resource and trap nest analysis

Little is known of the potential coevolution of flowers and bees in changing, biodiverse environments. Female solitary bees, megachilids and Centris , and their nest pollen provisions were monitored with trap nests over a 17-year period in a tropical Mexican biosphere reserve. Invasion by feral Apis (i.e. Africanized honey bees) occurred after the study began, and major droughts and hurricanes occurred throughout. Honey bee competition, and ostensibly pollination of native plants, caused changes in local pollination ecology. Shifts in floral hosts by native bees were common and driven by plant phylogenetics, whereby plants of the same families or higher taxa were substituted for those dominated by honey bees or lost as a result of natural processes. Two important plant families, Anacardiaceae and Euphorbiaceae, were lost to competing honey bees, but compensated for by greater use of Fabaceae, Rubiaceae, and Sapotaceae among native bees. Natural disasters made a large negative impact on native bee populations, but the sustained presence of Africanized honey bees did not. Over 171 plant species comprised the pollen diets of the honey bees, including those most important to Centris and megachilids (72 and 28 species, respectively). Honey bee pollination of Pouteria (Sapotaceae) plausibly augmented the native bees' primary pollen resource and prevented their decline. Invasive generalist pollinators may, however, cause specialized competitors to fail, especially in less biodiverse environments.  No claim to original US government works. Journal compilation © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 152–160.     

Preference of cabbage white butterflies and honey bees for nectar that contains amino acids

Summary Amino acids occur in most floral nectars but their role in pollinator attraction is relatively unstudied. Nectars of butterfly-pollinated flower tend to have higher concentrations of amino acids than do flowers pollinated by bees and many other animals, suggesting that amino acids are important attractants of butterflies to flowers. In order to determine whether amino acids are important in attracting butterflies and bees, we tested the preference of cabbage white butterflies (Pieris rapae) and honey bees (Apis mellifera) by allowing them to feed from artificial flowers containing sugar-only or sugar-amino acid mimics ofLantana camara nectar. Honey bees and female cabbage white butterflies consumed more sugar-amino acid nectar than sugar-only nectar. In addition, female cabbage white butterflies visited artificial flowers containing sugar-amino acid nectars more frequently than flowers containing sugar-only nectars; honey bees spent more time consuming the sugar-amino acid nectar. Male cabbage white butterflies did not discriminate between the two nectars. These results support the hypothesis that the amino acids of nectar contribute to pollinator attraction and/or feeding.     

Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae

The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.     

Zinc nutrition increases the antioxidant defenses of honey bees

Is the typical zinc (Zn) content of honey and pollen sufficient to meet the nutritional requirements of honey bees? To answer this question, and find the optimal dietary Zn levels for honey bees, we investigated the effects of varying dietary Zn levels on both captive worker bees and free‐flying honey bees, Apis mellifera ligustica Spinola (Hymenoptera: Apidae). We fed captive workers and free‐flying honey bees with 50% (wt/wt) sucrose solutions with Zn levels of either 0, 15, 30, 45, 60, or 75 mg kg^?1 diet and measured their Cu/Zn‐SOD activity, the mean survival time of captive bees, the Cu/Zn‐SOD activity of larvae, and the Zn concentration of royal jelly. Captive workers provided with 30 mg kg^?1 dietary Zn had higher Cu/Zn‐SOD activity and mean survival time than the control. Dietary Zn levels from 60 to 75 mg kg^?1 significantly increased the Zn content of royal jelly provided by colonies and the Cu/Zn‐SOD activity of larvae. Honey or pollen with a Zn content of <30 mg kg^?1 was insufficient to satisfy the maintenance nutritional requirements of bees that were not raising larvae. It therefore seems advisable to supply supplementary Zn to non‐brooding colonies when the Zn content of honey or pollen is <30 mg kg^?1. Honey or pollen with a Zn content of 60 mg kg^?1 was sufficient to satisfy the nutritional requirements for royal jelly production and to improve the health of larvae. It may therefore also be advisable to provide supplementary Zn to colonies with larvae when the Zn content of honey or pollen is <60 mg kg^?1.     

Seasonality of salt foraging in honey bees (Apis mellifera)

1. Honey bees (Apis mellifera) prefer foraging at compound‐rich, ‘dirty’, water sources over clean water sources. As a honey bee's main floral diet only contains trace amounts of micronutrients – likely not enough to sustain an entire colony – it was hypothesised that honey bees forage in dirty water for physiologically essential minerals that their floral diet, and thus the colony, may lack. 2. While there are many studies regarding macronutrient requirements of honey bees, few investigate micronutrient needs. For this study, from 2013 to 2015, a series of preference assays were conducted in both summer and autumn. 3. During all field seasons, honey bees exhibited a strong preference for sodium in comparison to deionised water. There was, however, a notable switch in preferences for other minerals between seasons. 4. Calcium, magnesium, and potassium – three minerals most commonly found in pollen – were preferred in autumn when pollen was scarce, but were avoided in summer when pollen was abundant. Thus, as floral resources change in distribution and abundance, honey bees similarly change their water‐foraging preferences. 5. Our data suggest that, although they are generalists with relatively few gustatory receptor genes, honey bee foragers are fine‐tuned to search for micronutrients. This ability likely helps the foragers in their search for a balanced diet for the colony as a whole.     

常见疾病、抗生素及农药对意大利蜜蜂(Apis mellifera ligustica)肠道微生物多样性的影响研究进展

蜜蜂是对农业生产十分重要的授粉昆虫。蜜蜂肠道微生物与蜜蜂健康有密切关系,但肠道微生物也会受多种外界因素的影响。本文就蜜蜂疾病、抗生素等蜂病治疗药物、农药,以及益生菌的应用等对意大利蜜蜂工蜂肠道微生物影响的研究进行了归纳总结,并对蜜蜂与其肠道菌关系研究进行了展望。     

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.