Apidologie最新文献

Yeasts are common symbionts of bumble bees and their nests, sometimes providing health benefits to their bee hosts. The mechanisms underlying these yeast-derived benefits remain unknown, though hypotheses include direct nutrition from ingestion of fungal cells, resource supplementation, or pathogen protection. We tested how adding living yeasts or their metabolic products to Bombus impatiens diets affects microcolony performance, including survival, reproduction, and pathogen presence. We additionally assessed effects of yeast treatments on diet (nectar and pollen) chemical composition using untargeted metabolomics. Yeasts had minimal impacts on colony performance. While yeasts slightly accelerated offspring production, some treatments also interacted with Aspergillus to reduce reproductive output. Yeast treatments slightly altered chemical composition of nectar, but most distinguishing compounds were unidentified. Our results suggest limited effects of yeasts via direct nutrition, resource supplementation, or modification of diets, instead suggesting that the effects of yeast supplementation are context-dependent, and more research is necessary to better understand the mechanisms underlying their impacts on bee hosts.

Pollinators assess their environment and make decisions on which flowers to visit. Several factors can affect flower choices, such as floral availability throughout a season, time of day, and temperature. Biological factors particular to a pollinator, such as the pollinator’s sex, their previous experiences during a foraging trip, and learning, can also play a role in decision-making mediated by color. Orchid bee pollination is intimately linked to foraging behavior. This paper presents the first study of orchid bee color vision use in Euglossa dilemma, and we focused on two aspects of color vision: (individual) color choice and preference (overall bias for a color). Blue and yellow emerged as the most effortless pair of colors to test, with 26.3% of males and 32.3% of females tested on this color completing the protocol. Our results show that humidity and time of day played a role on color choice. Individual male and female orchid bees showed variability in their color preferences in our tested colors. However, no clear patterns emerged for these bees overall. We also found that the preferences of bees are not significantly affected by the abiotic or biotic factors measured. Further, a bee’s preference was not predicted by its initial color choice. Decision-making and preference are complex aspects of pollinator behavior, with fitness consequences for the pollinator and the plants they visit. By testing orchid bees in the field with non-invasive tests, we can better understand how these tropical pollinators interact with their environment and make decisions based on their color vision.

The parasitic mite Varroa destructor is a main cause for honeybee colony losses. While population dynamics of V. destructor have been studied comprehensively within colonies and/or apiaries, little is known about spatio-temporal dynamics at larger geographic scales. In this paper, we demonstrate that surveys using ranked judgements of V. destructor prevalence and reported online by beekeepers can be used for analyses of population dynamics of V. destructor on a geographic scale. Prevalence indices calculated from the surveys’ data correlated significantly with published quantitative estimates of prevalence between 2013 and 2022 and predicted annual loss rates of honeybee winter colonies at regional and national geographic scales. The annual prevalence evolved in a similar manner among German regions but also revealed substantial variance in prevalence levels among regions. Retrospective epidemiological mapping revealed that geographic clusters of prevalence explained the variance within years. Between years, clusters with relatively low prevalence in 1 year tended to experience relatively higher prevalence than other regions in the following year. The pattern of population dynamics resembles spatial synchrony with population fluctuations and implies an auto-correlative response in annual prevalence trends and hence annual colony losses of honeybees. Online surveys using ranked judgements of V. destructor offer a low-cost method for estimating prevalence trends, which can be disseminated rapidly to beekeepers.

Survey and diversity studies carried out in four agro-climatic zones of Himachal Pradesh revealed that Bombus haemorrhoidalis Smith is the native bumble bee species widely spread from low lands to high altitude regions of the Himalayas. Therefore, rearing of bumblebees in captivity to produce mass culture is an important aspect to overcome the pollination services in greenhouse conditions. The efforts are being undertaken to commercialize the rearing of potential indigenous bumblebee species in India by the University of Horticulture and Forestry, Nauni, Solan, for its use in pollination. It was observed that the colony growth and development of this species in captivity were impeded due to their different feeding behavior and nutrition choice. Therefore, feeding behavioral studies of laboratory-reared colonies and natural nests of B. haemorrhoidalis, Smith, 1952 enable us to identify it as long-tongued species, as the average tongue length for the queen, male, and worker was found to be 13.30 ± 0.08, 11.15 ± 0.03, and 10.21 ± 0.03 mm, respectively, and also confirmed it as a pocket maker that forms pollen pockets near the brood clumps from which the larvae feed on the pollen mass itself. Therefore, identification of this feeding behavior makes us to understand its nutritional requirements and also enhances the possibility of rearing this species successfully under captivity by managing its nutritional stress and requirements.

The red dwarf honey bee (Apis florea), an open-nesting Asian species, has recently expanded its range beyond native regions, with populations documented in Egypt. Throughout 2023 and 2024, the public observed A. florea nests in Greater Cairo, despite previous predictions that suggested a likely distribution in the eastern, western, and northern regions, as well as the Nile Delta region. To gain a better understanding of their invasion and urban adaptation, we examined the morphometric characteristics of these populations in Egypt, as well as their preferred nesting sites in the urbanized areas of Greater Cairo. To do that, ten A. florea nests were sampled throughout Greater Cairo from 2023 to 2024, and 19 morphometric traits on worker honey bees were measured. Notably, all the nests investigated were found in highly urbanized areas of Greater Cairo, typically located on building hangings and balconies, metal pipes and railings, and home windows and doors, in contrast to previously reported common nest sites on vegetation (trees and shrubs). Significant morphometric variation was observed in 15 out of 19 traits among workers. Traits such as wing dimensions and body measurements exhibited regional variation, suggesting local adaptations influenced by environmental and genetic factors. Principal Component Analyses revealed clear geographic structuring among A. florea populations from Egypt and other countries, indicative of urban adaptations. These results emphasize the adaptability of A. florea to human-modified landscapes and its potential for further expansion and overall underscore the importance of monitoring A. florea’s spread, evaluating its ecological impacts, and assessing potential competition with native pollinators.

In light of the significant threat posed by declining honey bee populations to global ecosystems and agriculture, this study explores an innovative approach to face emerging pathogen threats. The present study investigates the efficacy of ground inflorescences from two Cannabis sativa genotypes as potential natural treatments for Nosema (= Vairimorpha) ceranae infection in honey bees. The plant genotypes analysed included a chemotype III selection, V1, with high cannabidiolic acid, and a chemotype I selection, V2, with a prevalence of tetrahydrocannabinolic acid. The inflorescences were incorporated into sugar candy at three concentrations w/w (1%, 2%, and 4%) and fed to bees that had been artificially infected with N. ceranae. Results showed significant differences in the survival of honey bees across treatments. All cannabis treatments reduced longevity compared to the control group. Notably, N. ceranae spore counts decreased in all treatment groups. Statistical analyses indicated that the control group experienced the highest increase in pathogen copies, while the fumagillin treatment maintained the lowest infection. Water and food consumption varied among treatment groups, with V1-2, V2-2, and V2-4 formulations leading to increased intake. The median lethal time for untreated bees was significantly longer than that for those treated with cannabis, while the survival of bees treated with V1-1 and V1-2 was longer than that of bees treated with fumagillin. These preliminary findings highlight the antimicrobial properties of cannabis inflorescences, highlighting cannabis as a potential natural intervention.

Plastic and microplastic (MP) pollution have emerged as a global environmental and health concern. Among these contaminants, textile microfibers (MF) constitute a major proportion of MP pollution. This study examines the presence of synthetic and natural MF in Apis mellifera bees and honey across Argentina, analyzing forager and nurse bees in three provinces and honey from multiple sources. Additionally, we investigated grooming behavior upon plastic microspheres and MF exposure as the transfer of these microplastics between exposed and cleaned bees. We detected similar levels of MF contamination in forager (206 MF) and nurse bees (186 MF). Honey samples were also contaminated (12.3 ± 8.67 MF in 500 g) and no correlation between population density and number of MF was found. Raman spectroscopy identified the origin of these MF as including both natural (cotton and wool) and synthetic (polyethylene terephthalate and polyacrylonitrile) MF. We also identified several dyes in the MF: anthraquinone-based pigments, copper-based phthalocyanines, and Indigo blue, which are commonly used to color synthetic polymers and natural fibers. Grooming frequency was significantly higher for bees exposed to plastic microspheres than for those exposed to MF. Additionally, our findings confirmed the transfer of both MF and microspheres from contaminated to clean bees, highlighting a potential pathway for MP dispersion inside hives. This work underscores the urgency of comprehensively addressing synthetic microplastics and natural textile fibers in ecosystems, and their long-term ecological implications given their risks to honeybee health, pollination efficiency, and food safety.

To better understand the genetic diversity, population differentiation, and maternal origin of eastern honey bees (Apis cerana) in Sichuan Province, China, we analyzed mitochondrial DNA cox1 sequences from 10 geographical populations. A total of 308 cox1 gene sequences were obtained, forming 41 distinct haplotypes. The average haplotype diversity (Hd) was 0.833, and the average nucleotide diversity (Pi) was 0.00188, indicating a high level of genetic diversity in A. cerana populations in Sichuan. Notably, Hap3 was identified as the most frequent and widely distributed haplotype, suggesting it may represent the ancestral haplotype of A. cerana in this region. Analysis of molecular variance (AMOVA) revealed that the majority of genetic variation was concentrated within populations. Pairwise fixation index (Fst) and gene flow (Nm) results showed that a significant genetic differentiation was observed in population from Aba (AB), Batang (BT), and Derong (DR) compared to other regions, with mountain barriers potentially driving this spatial genetic structuring. The haplotype phylogenetic tree and haplotype network analysis further revealed that haplotypes from DR and BT clustered into two independent groups, suggesting unique genetic characteristics in these areas. Neutrality tests suggested potential historical demographic expansion in A. cerana populations from Sichuan. These findings demonstrate that Sichuan’s A. cerana populations maintain rich genetic diversity with significant geographic differentiation, providing critical insights for formulating regional conservation strategies and sustainable utilization of this ecologically important pollinator.

Megachile rotundata, the alfalfa leafcutting bee, is a managed solitary bee used to pollinate alfalfa for seed production in North America. These bees exhibit a unique life cycle where an individual either completes development to adulthood in summer without a diapause period or enters diapause as a prepupa, which is the overwintering life stage. Although various external factors are shown to influence diapause outcomes, the underlying mechanisms that determine these two developmental pathways are unclear. To better study when and how diapause outcomes are determined in immature bees, we investigated the likelihood that siblings occupying adjacent cells in their nest would experience the same diapause fate. We collected nests from commercial bee aggregations in alfalfa fields. The first two cells were excised from hundreds of nests collected on the same day, and only cells containing eggs or first instars were retained and then monitored over time. We recorded whether an offspring developed directly to the adult stage or remained in the prepupal stage through the fall for overwintering. Our findings revealed that across the nesting season, 91% of cell-adjacent siblings had the same diapause fate. However, time of year was a factor in how likely these siblings were to have the same fate. Near the summer solstice, only 76% of adjacent siblings had a matched diapause fate, whereas several weeks before or after this period, siblings’ fates were nearly 100% matched. Additionally, egg to prepupa development for non-diapausing offspring was about five days faster than for diapausing offspring.