Apidologie最新文献

Honey bees (Apis spp.) are important pollinators in many natural and agro-ecosystems across the world. Effective means of surveying wild populations are therefore key to their conservation and management. One available survey method infers honey bee colony density from the genotype of drones (males) sampled from sites known as Drone Congregation Areas (DCAs). While this approach has been commonly used for the Western honey bee (A. mellifera), its feasibility for other Apis species is unknown. Here, we investigate drone congregation behaviour in the Asian honey bee Apis cerana in north-east Australia and its suitability for inferring colony density. As this A. cerana population is invasive, surveys in this case can aid in monitoring the population’s growth and spread. Over 5 years, we identified 30 DCAs, many of which were stable across time. DCAs were sheltered areas beside tree-lines or openings in the forest canopy. A. cerana drones joined DCAs during 1–2-h afternoon intervals and could be sampled at heights of 2–24 m via adhesive lines attached to helium balloons carrying lures coated in queen pheromone. Drones were more likely to be present at a DCA as temperature increased, though abiotic factors did not predict overall drone abundance. Drones could be sampled in low numbers even where colony density was extremely low. Based on the genotyping and inferred sibship of drones sampled at DCAs between 2016 and 2021, we estimate population density in Australia’s A. cerana to be in the range 1.1–8.1 colonies/km². This extrapolates to a total population size in the range 11,000–83,000 colonies, with more refined estimates requiring better knowledge of drone flight distance and the effect of habitat on colony density. We conclude that population surveys based on drones from DCAs are possible for A. cerana and propose that this approach be part of a toolkit of methods used to monitor Asian honey bee populations in both their native and invasive ranges.

An economically sustainable production of royal jelly (RJ) requires the use of genetics specifically improved for this very demanding trait. The French Royal Jelly Association has developed since 2010 a selection plan for that purpose, based on a collective data recording system and the initial seedstock of five French beekeepers. The aim of this study was to evaluate the efficiency of this collective breeding program, a decade after its concrete start. We considered three different genetic models to describe the phenotypes, hereafter named the Colony, Worker, and Queen Models. We showed that when the size and the structure of the dataset are insufficient to fit a Colony Model, fitting a Queen Model gives more understandable results for practical use of the estimated breeding values than the Worker Model. Regarding genetic parameters, we estimated moderate to high heritability values for all traits, regardless of the genetic model. Under a Queen Model, heritability estimates of RJ production were 0.19 ± 0.09 and 0.35 ± 0.13 for first and second harvests, respectively; the estimates were 0.76 ± 0.08, 0.29 ± 0.09, and 0.22 ± 0.08, respectively, for the calmness, gentleness, and spring development of the colony. We also proved that the breeding program is efficient, increasing the production at second harvest of 3.5% per year on average. Attention must, however, be paid to the evolution of inbreeding in this very small breeding population. Few genetic correlations were significantly different from zero between the traits, due to large standard errors of our estimates. It is, however, worth to note that the trends were generally favorable between all traits, which appears encouraging to improve production and behavioral traits jointly in the breeding program.

Urbanization, agriculture, and climate change have known negative impacts on global bee populations, but malnutrition as a result of disrupted or altered floral resources also hinders bee survivorship. Hence, understanding the nutritional content of pollen—the main source of protein, minerals, and lipids required by bees—is paramount to capture the requirements of a balanced diet to support bee health. Here, we characterize the non-esterified fatty acid (NEFA) and amino acid (AA) content of 22 pollen species from 11 families commonly found in eastern North America, to assess their nutritional profile and importance to bee diet. We found that total NEFA content was highly variable across pollen families and genera, but essential fatty acids omega-6 and omega-3 were the most abundant across the majority of pollen species. Total AA content was also diverse across pollen families and genera, and the presence of ten essential amino acids was detected in all pollen species (except for methionine in Rhus glabra). P:L ratios ranged broadly from 2.9 in Trifolium sp. to 74.4 in Prunus sp., but omega-6:3 ratios were generally below one for the majority (73%) of studied pollen species. Phylogenetic comparisons detected a significant negative correlation between essential AA against total NEFA and total omega content, suggesting potential trade-offs with lipid and essential AA in pollen nutrition. Our findings suggest that multiple pollen species have the potential to be considered a valuable source of protein and lipid, and that a diversity of flora is essential to meet diverse bee diet and nutritional needs.

Pollinators navigate a complex and dynamic nutritional landscape while foraging for floral resources. Bees are a group of flower-visiting insects that rely on pollen as their sole protein source, and thus, bees have strong incentives to seek pollen with high protein content. Indeed, research has shown that bees may prefer to visit flowers with high-protein pollen, but the mechanisms by which bees are able to detect plants with this high-protein pollen are unknown. One hypothesis is that plants with high-protein pollen advertise this resource quality through volatile emissions. We established 17 native perennial plant species from three plant families (Fabaceae, Asteraceae, and Lamiaceae) in a large field experiment to explore the relationship between nutritional quality, inflorescence volatile emissions, and pollinator visitation. We sampled twenty garden plots composed of these native plant species for 2 years. Our results showed that floral morphology significantly affected pollinator visitation; floral morphology that restricted the accessibility of floral resources reduced the overall foraging female bee visitation rate. In contrast, the visitation rate of foraging female bumble bees was higher on plants with floral morphology that restricted access. Moreover, we showed that (1) plants with less accessible inflorescences had significantly higher pollen protein content and (2) lower volatile emissions, while (3) there was a significant interaction between accessibility and pollen protein for foraging female honey bee visitation; honey bees preferred accessible flowers with lower pollen protein. We found no evidence in support of the hypothesis that floral volatiles advertise pollen protein content. Overall, floral accessibility related significantly to both floral volatile emissions and pollen protein content, determining both the identity of floral visitors and affecting the frequency with which they visited.

Bee venom (BV) extraction has become a standardized practice, characterized by being safe, simple, and causing no harm to bees. Though it demonstrated significant antimicrobial activity, its potential activity against honey bee pathogens have yet to be investigated. Therefore, we investigated for the first time in a controlled laboratory setting the effectiveness of BV administration in sugar syrup against Vairimorpha (Nosema) ceranae, a globally widespread fungal disease of honey bees. To do this, we first determined the BV lethal concentration (LC₅₀), after which newly emerged bees were inoculated with V. ceranae spores (10⁵) or/and chronically fed sugar syrup containing BV at LC₁₀ (0.24 mg/mL) or LC₂₀ (0.34 mg/mL) ad libitum for 12 days. The effects on bee longevity (time to death) were studied. The intensity of V. ceranae and total hemocyte count (THC) were also studied 6 and 12 days after infection. The expression of four antimicrobial peptides (AMPs) encoding genes (defensin1, apismin, hymenopteacin, and PGRPS2) was also measured after 6 days in midgut tissues. We discovered that BV increased bee survival and significantly reduced Vairimorpha intensity. This effect was associated with an increase in THC as well as the expression of the AMP-encoding genes studied. BV’s effects appeared to be concentration- and time-dependent, with a more profound decrease in Vairimorpha intensity at day 12, especially in bees fed BV at LC₂₀. These findings highlight BV’s potent immunomodulatory role against fungal pathogens in honey bees, and its potential role against other bacterial and viral pathogens should be investigated.