Apidologie最新文献

Climate-driven shifts in bumblebee emergence and flowering time can disrupt plant reproduction and affect pollinator health. To study such mismatches, accurate phenological data is crucial but challenging to collect, especially for pollinator hibernation emergence. Citizen science is increasingly being used to expand the spatial and temporal scope of data collection in research. Nevertheless, these data can be biased due to different reasons. We found that 33.14% of records in Europe and 32.47% in North America were gathered on weekends – exceeding what would be expected by random chance and showing opposite patterns to bumblebee museum specimen records. Bias also affected queen emergence date and varied by species, suggesting that species-specific traits may mediate the bias extent. We also present a case study showing how adjusting for day-of-the-week effects can change the statistical significance of temporal trends in bumblebee emergence dates. We thus recommend including the day of the week in statistical models to account for temporal biases. Our findings highlight the importance of correcting temporal biases in citizen science data to ensure accurate evaluations of ecological responses to climate change.

Managed honeybees play a crucial role in enhancing agricultural crop production and plant biodiversity conservation and ensuring food security. However, beekeepers, especially those in the Northern Hemisphere, are experiencing high honeybee colony losses, mainly due to the ectoparasitic mite Varroa destructor. This could threaten our future food security. The presence of V. destructor has also been reported in Africa; however, honeybees are less affected by the mite. Moreover, local beekeepers do not consider the mite as a threat to their colonies, and colonies survive without mites’ treatment. Mite-resistant honeybee populations have also been reported in various parts of Europe, but they are limited in number and confined to specific regions. Therefore, understanding why mite-resilient honeybee populations are flourishing in many African countries is crucial for developing effective management strategies to improve honeybee health worldwide. Hence, this review synthesizes existing knowledge about the factors and traits that allow mite-resilient honeybee populations in Africa to flourish and aims to translate the insights gained from Africa into more effective approaches for managing the impact of V. destructor worldwide. The results suggest that African-derived honeybees are resilient to a broad set of threats including V. destructor because they live in harmony with nature. Resilience is attributed to a more bee-friendly environment, to better balanced colony densities, to beekeepers’ management practices, and to the bee’s behavioural adaptation and physiological and genetic traits. Nature-based beekeeping practices that allow natural selection to operate and maintain the genetic diversity of local honeybee subspecies are the key to their resilience against V. destructor.

Honey bees (Apis mellifera L.) can be considered interesting biosamplers for monitoring the contaminants they may accumulate as a function of distance and time since they are exposed to these compounds either directly or indirectly. The aim of this research was to investigate how the levels of essential and non-essential trace elements in honey bees and plants are altered by hive management (organic or conventional), agricultural practices, and seasonal conditions. The levels of iron, zinc, copper, lead, and cadmium were determined in honey bees and wild plants from six different apiaries located in four Italian regions using atomic absorption spectrometry. Iron was the most abundant essential trace element, followed by zinc, while copper was an order of magnitude less abundant. Honey bees from conventional farms had significantly higher copper levels than those from organic farms. Regarding the non-essential elements, only honey bee samples from apiary 6 (conventional) showed cadmium levels of around 0.1 µg/g wet weight, and only some samples from apiary 4 (conventional) showed an average lead level of 0.83 µg/g wet weight. Among the factors tested, the season (spring and summer) and the apiary management were critical factors affecting content of trace elements in honey bees. In particular, the season is the one that has the greatest influence on element content, highlighting the possible adverse effects of climate change on honey bee health.

Trigona comprises 35 species, of which 25 occur in Brazil. Of these, 12 species have been cytogenetically investigated and most showed the chromosome number 2n = 34, except for Trigona braueri, which showed 2n = 32, due to a probable numerical reduction by chromosome fusion. In this study, Trigona pellucida was cytogenetically analyzed by classical and molecular techniques (Giemsa staining, CMA₃/DAPI fluorochrome staining and FISH using 18S rDNA, telomeric and microsatellite probes). New chromosome numbers, n = 10 and 2n = 20 and the diploid karyotypic formula 2 k = 14 M + 4SM + 2A were described. These new chromosome numbers were quite divergent from the other Trigona and such intrageneric variation was unexpected in the tribe Meliponini. CMA₃/DAPI fluorochromes staining showed CMA₃ positive segments in all chromosomes of T. pellucida, which was also divergent from other Trigona species. In situ hybridization with 18S rDNA probes occurred on the short arm of both chromosomes of the ninth pair, which also coincided with CMA₃⁺ regions. Microsatellite probes showed markings on all chromosomes, and in seven pairs these markings occurred in the terminal regions of both arms. FISH with telomeric probes showed regular markings in the terminal regions of the chromosomes. The present result with Trigona pellucida was surprising, and pose more challenges for understanding the karyotypic evolution of stingless bees than previously assumed.

Understanding which ant species interacting with honeybees can transmit or acquire viruses is crucial for managing honeybee health. Our objective was to develop a new methodology using two indices, based on a per-hive approach, to identify ant-virus combinations with high transmission potential (Matching Index) and to assess the relative risk posed to honeybees (Risk-to-Bee Index). Our survey in apiaries in Buenos Aires Province, Argentina, revealed that honeybee hives more infested by ants had smaller colonies. The Argentine ant, Linepithema humile, was among the top three ant species infesting hives. Ant brood and queens showed higher virus detection rates compared to workers, increasing virus prevalence in ants. Four viruses were detected in L. humile, but only deformed wing virus (DWV) was more prevalent in honeybees in hives with L. humile. Argentine ants tested negative for chronic bee paralysis virus, which was common in Camponotus species. In our study, per-hive indices suggest that Argentine ants would transmit DWV and black queen cell virus to honeybees, while honeybees would transmit DWV and acute bee paralysis virus to Argentine ants and Camponotus mus. Importantly, although our indices are simpler than previous tools to evaluate interspecific virus transmission, they do not provide definitive conclusions. However, the suggestions they offered align with all existing empirical data, highlighting their robustness. Thus, this approach provides a novel tool for prioritizing research on high-risk virus transmission between honeybees and ants, emphasizing its potential impact on honeybee management.

Previous work from our group identified distinct microbiome profiles in thriving versus non-thriving honeybee colonies in southwest Ireland, and highlighted seasonality, rather than location, as a significant factor in microbiome dynamics. Ireland harbours a relatively pure population of Apis mellifera mellifera, a subspecies in decline across mainland Europe, that is threatened by introgression from imported honeybee types such as the Buckfast hybrid and C-lineage honeybees. In this pilot study, we identified mitotypes of 30 honeybee colonies across southern Ireland and sequenced the nuclear genome of 9 colonies to assess hybridization levels. We profiled the microbiome of these colonies to investigate if mitotype interacted with the microbiome. Of the 30 colonies tested, 18 were M-mitotypes, but 9 C- and 3 A-mitotypes were also detected. Nuclear genome SNP analysis revealed that M-mitotype colonies were relatively pure, displaying little to no introgression, whereas A-mitotypes displayed a hybridised genome predominantly composed of M-lineage SNPs. C-mitotype colonies also displayed varying levels of M-lineage SNPs. Microbiome composition did not differ significantly across mitotypes, with individual colony being the most significant determinant of microbiome diversity. These findings provide further evidence that the Irish honeybee population is predominantly composed of native M-lineage honeybees, though its genetic integrity is threatened by the presence of imported lineages. While this native population does not possess a unique microbiome compared to that of other lineages, these results further our understanding of factors which determine the microbiome composition of honeybee colonies in Ireland.

The choice of honey bee genetic stock represents an important management decision for beekeepers to improve resilience against biotic and abiotic stressors impacting their operations. Three different genetic stocks of honey bees (Pol-line, Russian and Italian) were monitored in southern Arizona field experiments for two successive 9-month periods (June to February). Continuous monitoring techniques and detailed hive assessments were used to measure differences in colony performance and behavior. On average, Italian colonies produced significantly more brood compared to both Pol-line and Russian bees and had significantly more foragers and adult bees on average than Pol-line colonies. However, both Pol-line and Russian colonies exhibited a faster rate of weight gain during the primary nectar and pollen flow season (June–September) and slower weight loss during the dearth season (October–February) compared to Italian colonies, which corresponded to results from published cage studies. Pol-line colonies started flight activity 10 min later on average than Italian colonies and ended daily flight activity about 30 min later on average than Russian colonies. There were no internal hive temperature differences among bee stocks, but Pol-line colonies maintained the highest carbon dioxide (CO₂) concentrations. Finally, Varroa mite levels in Pol-line and Russian colonies were significantly lower than Italian colonies and were correlated with brood area. Our findings highlight the potential advantages of Russian and Pol-line bees for use in commercial beekeeping operations. These observed stock differences could translate to improved crop pollination efficiency and reduced reliance on chemical mite controls.

From 1984 to 2015, the Bee Disease Diagnostic Lab at the USDA-ARS Beltsville Bee Research Laboratory (MD, USA) analyzed 66,056 samples submitted for disease diagnosis, comprising 35,883 adult bees and 30,173 brood samples collected from symptomatic colonies nationwide. This dataset provided valuable insights into honey bee disease dynamics over three decades. Adult bee samples were screened for Nosema spp. and tracheal mite (Acarapis woodi). Brood samples were microscopically analyzed for the presence of both Paenibacillus larvae and Melissococcus plutonius, the causative agents of American foulbrood (AFB) and European foulbrood (EFB) diseases, respectively. Antibiotic resistance was tested in AFB-positive samples (n = 6,785) for tetracycline and tylosin. Longitudinal analysis revealed significant (p < 0.001) inter-state and seasonal differences in disease prevalence. AFB was significantly more prevalent nationwide (44.71%) compared to EFB (10.01%), with a negative correlation between the two diseases (R = -0.4, p < 0.01). P. larvae resistance to tetracycline and tylosin declined significantly (p < 0.001) in later years, with national resistance averages of 42.52% and 27.78%, respectively. Additionally, positive correlations were recorded between AFB prevalence and P. larvae resistance to both antibiotics. Nosema spp. prevalence ranged from 0% to 77.9% across states, with a national average of 24.09% and significant seasonal variations (p < 0.001). From 2008 to 2015, Nosema infection rates increased significantly, contrasting with a marked decline in tracheal mite prevalence since 2007 (national average of 12.48%), which was negatively correlated with Nosema infection (R = -0.3, p < 0.05). This study provides unprecedented longitudinal insights into honey bee disease dynamics in the United States, highlighting the significant emergence of EFB and Nosema as threats from 2008 to 2015 and a drastic reduction in tracheal mite prevalence. These findings underscore the need for continued monitoring and adaptive management strategies to protect honey bee health and ensure sustainable pollination services.

Female (diploid) honeybee (Apis mellifera) larvae are developmentally plastic and may become either queens or workers, depending on the nutritional stimuli received during the larval stages. Caste-specific diets activate distinct regulatory networks, leading to differential expression of coding and non-protein-coding genes, splicing variants, differences in the chromatin structures, and DNA methylation patterns, as well as variations in proteomic landscapes and the activity of key signaling pathways. Previous studies have reported the involvement of RNA epigenetics in honeybee caste fate. To further explore this and gain new insights on RNA modifications in caste diphenism, we predicted m⁶A and m⁵C RNA methylation sites in differentially expressed transcriptomes of the fourth instar larvae (L4) of queens and workers. We showed enriched functions among upregulated transcripts in L4 workers with predicted m⁶A and m⁵C sites, such as the metabolism of macromolecules and juvenile hormone synthesis. In L4 queens, these sites were predicted in upregulated transcripts that participate in mitochondrial energy metabolism, cytoskeletal organization, transport, and localization of molecules. Our findings add relevant information and novel perspectives on the potential role of the epitranscriptomic layer in the complex molecular interactions that guide the process of caste differentiation.