Apidologie最新文献

Heavy metals can naturally accumulate in the environment, but industrialization and the use of certain agrochemicals are associated with metal pollution. Despite the extensive use of pesticides in Brazilian croplands, little is known about heavy metal contamination in native bee species. Such contamination could potentially have negative consequences for both the ecosystem and the economy. In this study, we focused on Xylocopa frontalis, a facultative solitary bee that is an important pollinator of crops, especially yellow passion fruit (Passiflora edulis f. flavicarpa), which is economically significant in several regions of Brazil. We investigated the levels of essential elements and heavy metals in the larval food of X. frontalis nests from three fragments of native Brazilian savanna and three passion fruit crops. Our results indicated that samples from yellow passion fruit crops did not show higher levels of chemical contamination compared to those from Brazilian savanna areas. Our findings reveal that bee bread collected from nests of X. frontalis, a large, generalist, and facultatively social bee, contains elevated levels of Al, Zn, and Sn in both agricultural and preserved areas of the Cerrado. These results highlight the potential risk posed by environmental contamination even in areas considered relatively undisturbed and underscore the importance of monitoring multiple potentially toxic elements in wild bees to support the conservation of pollinator diversity and the continuity of their ecosystem services. Moreover, the analysis of such elements in pollen may serve as an effective bioindicator of heavy metal contamination in terrestrial ecosystems.

The increasing use of pesticides has been identified as a major driver of pollinator decline. Thiamethoxam, a neonicotinoid pesticide, poses a significant threat to neotropical bees by impacting behavior and physiology. Despite the ecological importance of stingless bees, little is known about the effects of pesticides on these species. This study investigated the effects of a sublethal concentration of thiamethoxam on the Malpighian tubules (key organs responsible for excretion and detoxification) in Melipona scutellaris. Using immunolabeling techniques, we analyzed the expression of heat shock proteins (HSP70 and HSP90) and cellular stress biomarkers, and evaluated cell death through the TUNEL method. Results showed an increase in HSP70 expression on day 1 of exposure, followed by a decrease on day 8, while HSP90 exhibited the opposite trend. The observed pattern for HSP70 suggests that the Malpighian tubules initially responded to oxidative stress caused by acute exposure (1 day), while after 8 days, other metabolic responses or pathways may have been activated to counteract cellular stress. In contrast, the pattern for HSP90, which was opposite to that of HSP70, may indicate a compensatory response, with increased HSP90 levels potentially protecting the Malpighian tubules as HSP70 levels declined. Additionally, TUNEL assays revealed minimal DNA fragmentation by the eighth day of exposure. These findings highlight the complex response of M. scutellaris to TMX and underscore the need for further ecotoxicological research on stingless bees to better understand the impacts of pesticides on non-target species.

In South Africa, clinical signs of American foulbrood (AFB) are limited to the province of the Western Cape, infecting Apis mellifera capensis. Currently, colony-level virulence of AFB field strains and overall resistance of A. m. capensis colonies to AFB are unknown. We evaluated hygienic behaviour and colony AFB resistance in 15 full-sized A. m. capensis colonies. Eight colonies originated from a population previously exposed to AFB and seven colonies were from an AFB-unexposed population. Firstly, hygienic behaviour of all colonies was assessed by the freeze-killed brood assay. Twenty percent of all colonies removed more than 95% of frozen brood in 24 h, while a further 26.67% removed more than 95% of dead brood in 48 h. There were no differences between the two populations in the level of hygienic behaviour. Secondly, we infected the same A. m. capensis colonies with the ERIC I subtype Ab field strain of P. larvae with a dose of 90 CFU/larva. We monitored colonies for 6 months, quantifying brood production, brood patchiness, and the number of brood cells infected with AFB. The P. larvae field strain had high virulence for all colonies regardless of previous AFB exposure or level of hygienic behaviour. The disease progressed slower in the AFB-unexposed population than in the AFB-exposed population. Colonies that removed 95% or more dead larvae within 48 h showed lower proportions of AFB infection than colonies expressing poor hygienic behaviour, which suggests that hygienic A. m. capensis colonies are more resistant to AFB.

Melipona beecheii is the primary species used for meliponiculture in the Yucatan Peninsula. However, both the bees and meliponiculture are at risk due to deforestation and habitat disturbance. Although some studies have explored the food resources utilized by M. beecheii in the region, the relationship between these resources and the characteristics of the vegetation surrounding the meliponaries has not been examined. Consequently, we conducted a palynological study of pot-pollen from 29 colonies located across the three primary vegetation types of the Yucatan Peninsula. We analyzed our findings using existing descriptions of the meliponaries’ vegetation. Approximately 1500 pollen grains were counted per sample, comprising 69 pollen morphotypes. We identified 40 species, 45 genera, and 27 plant families, with Fabaceae and tree plants predominating. Meliponaries located in semi-evergreen forests exhibited the highest pollen richness, although similarities in richness and in the number of effective and dominant species were noted among the meliponaries in different vegetation types. We also observed varied pollen composition among vegetation types and a significant positive correlation between plant richness and pot-pollen richness. However, this relationship did not extend to the number of effective or dominant species. No relationship was found between the relative abundance of plant pollen on meliponaries and the absolute density or cover of these plants in the vegetation surrounding the meliponaries. Our results indicate that M. beecheii selectively favors pollen from a small group of tree species while maintaining a diverse diet, probably to ensure that the colony obtains all essential nutrients.

Honey bees (Apis mellifera L.) play a crucial role in pollination, and their olfactory system is essential for food collection and source selection. This study evaluates how the deformed wing virus (DWV), particularly its variant A, affects the olfactory sensitivity and behavioral responses of bees (10 to 20 days old) to volatile compounds from different pollen sources. We collected and analyzed the volatile fractions of three types of pollen (polyfloral and two monofloral) using dynamic HeadSpace and gas chromatography–mass spectrometry (GC–MS). The chemical analysis revealed differences in volatile compound profiles among the pollen types, including the presence of benzaldehyde, lilac alcohol, and 1–4 cineole, which are known to impact honey bee olfaction. Behavioral assays using a Y-olfactometer showed that while non-inoculated bees (N-DWV) responded to the aromas of all pollens in higher proportions, DWV-inoculated bees (I-DWV) exhibited significant reductions in behavioral responses. Specifically, I-DWV bees showed lower response rates, and a higher proportion of non-responding individuals compared to N-DWV bees. Notably, I-DWV bees were more attracted to the aroma of Eucryphia cordifolia when exposed simultaneously to the aroma of Rubus ulmifolius. This preference may be related to specific volatiles emitted by E. cordifolia that signal higher nutritional or medicinal value. Future analyses focused on the antiviral activity of this pollen could help clarify whether such attraction is associated with adaptive mechanisms against viral infection. Additionally, electrophysiological recordings indicated that DWV-A infection decreases olfactory sensitivity, particularly in response to complex odors. This decline in olfactory function and behavioral preferences could compromise foraging efficiency and overall colony health. These findings highlight the impact of DWV-A on honey bee sensory and behavioral processes, raising concerns about broader implications for colony survival and pollination services.

Honeybees are essential global pollinators and key model organisms for studying insect social behavior. Genetic manipulation is crucial for understanding honeybee biology, but current methods rely on microinjecting early-stage embryos, which is technically challenging, inefficient, and often results in high embryo mortality. In this study, we identified AcQP, an ovary-targeting peptide from the Asian honeybee (Apis cerana), capable of delivering DNA specifically to ovarian cells and transmitting it to progeny via the laying queen. Notably, AcQP also targets the ovaries of Apis mellifera and other non-Apis species, including silkworms and mosquitoes. By integrating AcQP with the Gal4- upstream activation sequences system, we successfully introduced exogenous DNA into queen bee ovarian cells via abdominal spiracle injection. This study established an efficient ovary–targeted DNA delivery method, representing a significant advancement in honeybee genetic engineering.

Bumblebees (Bombus spp.) are essential pollinators in a wide range of ecosystems, including agricultural systems. Addressing the critical knowledge gap in species-specific nutritional requirements, which leads to inconsistent colony development in native bumblebees like Bombus eximius, this study investigated the effects of pollen diet on microcolony development and reproduction. We examined the effects of three monofloral pollen diets, namely, Brassica napus, Camellia sinensis, and Zea mays, on worker egg-laying, drone larval development, lifespan, and gene expression. Our findings revealed that pollen nutritional quality significantly affected reproductive output, including the preoviposition period (time to first egg) and oviposition periods (duration of egg-laying), as well as offspring development in bumblebees. Worker bees fed C. sinensis and B. napus pollen exhibited significantly higher expression of the vitellogenin (encoding a yolk protein precursor crucial for oocyte development and egg production) and hexamerin (encoding a major storage protein vital for development and amino acid reserves) genes in their abdomens than did those fed Z. mays pollen. Microcolonies fed C. sinensis pollen demonstrated the highest reproductive success, the shortest mean semi-generation time, and the longest lifespan, indicating its superior nutritional quality for B. eximius. These results highlight the critical role of pollen nutrition in bumblebee health and suggest that C. sinensis pollen could enhance the performance of managed bumblebee colonies.

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.