Apidologie最新文献

Honeybees (Apis mellifera) play a crucial role in agricultural productivity and the sustainability of ecosystems. However, environmental stressors and insufficient nutrition can adversely affect the health and colony resilience of these important insects. This study investigated the effects of different protein substitute patties on honeybees’ physiological and behavioral responses. The research evaluated levels of the HSP70 stress protein in the bees’ brain tissues, HSP70 immunohistochemical staining in hypopharyngeal glands (to assess tissue-specific stress localization), Malpighian tubule diameters, and aggression scores. Statistically significant differences were observed among groups. Patty consumption levels and gut weights also varied significantly. Patties containing spirulina (Patty II) were associated with beneficial effects on Malpighian tubule length and stress protein levels, whereas patties containing active fresh yeast (Patty V) induced elevated HSP70 levels, potentially signifying metabolic stress. Increased aggression levels were observed in groups fed with type II and type III patties. In contrast, the control group, fed natural pollen, displayed low HSP70 levels and balanced aggression scores. These findings highlight that protein substitute patties on honeybee health and colony performance are relatively multifaceted and that patties ought to be optimized considering palatability, bioavailability, and physiological effects. Our study provides valuable insights for the improvement of bee nutrition strategies and the enhancement of their resistance against environmental stressors.

How environmental stressors such as pathogens affect thermoregulatory and thermal tolerance traits in bumble bees is poorly understood. We hypothesized that a challenge to the bumble bee immune system may negatively affect these traits due to the energy investments required for immune responses and maintenance of thermal homeostasis. Bumble bee workers exposed to a 24 h, non-pathogenic immune challenge (i.e., heat-inactivated bacteria) demonstrated significantly reduced thoracic temperature during recovery from chill coma and significantly reduced tolerance to exposure to temperatures ≥ 40 °C compared to bees in control groups. In addition, immune challenged bees were in poorer conditions that control group bees when allowed to recover from heat tolerance assays for 4 h. The 24 h immune challenge did not affect body total lipid content of head, thorax and abdomen available to worker bees prior to the chill coma recovery and heat tolerance assays. We discuss our findings in the contexts of bumble bee colony health and broad extrapolation of laboratory findings to natural systems.

Eusocial insect queens often use pheromones to prevent reproduction in the worker caste, enforcing the reproductive constraint that is central to eusociality. In A. mellifera honeybees, the queen emits several pheromones that affect worker reproduction, the most important being QMP. Although the effects of QMP have been studied in some detail, the mechanisms by which it brings about reproductive constraint in workers are still unclear. Remarkably, QMP is also able to repress reproduction in other insects, including the fruit fly Drosophila melanogaster, in which QMP has been shown to induce a starvation-like response. Here we use caged newly eclosed workers with an ad libitum choice of protein and sugar food sources to investigate whether QMP alters dietary intake in the honeybee. We show that initially, irrespective of QMP exposure, workers only consume protein, before shifting to carbohydrate after 4 days. We also show that QMP exposure results in an increased preference and intake of carbohydrates in worker bees, raising the possibility that QMP also induces a starvation-like response in honeybees.

Agricultural intensification and land-use changes have led to an increase in monocultures, reducing the diversity of polliniferous resources. Honey bees (Apis mellifera) are particularly sensitive to this reduction, which has been associated with large-scale colony losses worldwide. Reduced pollen diversity impairs nutrient intake and leads to nutritional stress. Eucalyptus grandis monocultures offer a suitable context to study this problem, as their pollen is nutritionally poor, with low protein and lipid content, and a deficiency in essential amino acids. In these environments, colonies suffer nutritional stress, become infected with the microsporidium Nosema ceranae, and weaken, which may lead to colony loss. In this study, we evaluated strategies to mitigate the impact of nutritional stress. Five groups of colonies were placed in an E. grandis plantation and received different protein supplements: Apiprot, Feedbee, and a novel nutritional formulation (UFP). Two control groups were included: one without supplementation and the other supplemented with polyfloral pollen patties. Besides that, all colonies had access to the environmental pollen (mainly E. grandis pollen). Protein supplementation increased brood and adult populations, as well as honey production, compared to negative controls. Interestingly, RNA viral levels were higher in supplemented colonies, although no negative effects on colony strength were observed. These findings suggest that protein supplementation is an effective strategy to mitigate nutritional stress in E. grandis plantations. This work contributes to a better understanding of the impacts of land-use intensification on honey bee health and offers tools for mitigation.

Females of all Monoeca species have strong hooked bristles on the mesosomal venter, leg bases, and metasomal sterna (2–4), which suggests that they could be related to pollen collection; however, this has not been proved. These females show a strong association with species of Malpighiaceae that provide sources of oil and pollen. To prevent/reduce spontaneous self-pollination, most Neotropical Malpighiaceae species have a stigmatic cuticle that prevents the germination of self-pollen grains while intact. We performed field observations and offered virgin flowers to Monoeca females. Our results show that the hooked hairs of Monoeca species collaborate in the pollen collection from the anthers and could break the stigmatic cuticles during their stereotyped oil-collecting behavior.

Honey bees are possibly unique amongst managed animals in that a significant part of their global population is wild. More data regarding wild colony density and survival are needed to assess the size and status of wild populations in the honey bee’s native range. Previous studies from parts of central Europe have reported low densities (<0.5 colonies/km²) and annual survival rates (<0.15) of wild colonies, indicating that they might just be swarms that have escaped from apiaries in some places. Here, we report the results of a 3.5-year monitoring study of wild colonies living in wood pasture, parkland and deer parks (“landed estates”) in southeast England. Sixty-three honey bee nest sites were found across six landed estates and checked three times a year to determine colony survival rates. Wild colonies occupied cavities in trees (89%) and buildings (11%) at an average density of 2.5 colonies/km². We found no evidence of spatial aggregation amongst active nest sites, although there was a significant positive association between wild colony occurrence and veteran tree distributions. Wild colonies had an annual survival rate of 0.41, meaning that colonies active in late spring and early summer would need to produce an average of 1.4 swarms each year for the population to be self-sustaining, which is within the range of swarming rates reported for unmanaged colonies. Our results suggest that wild honey bee colonies on landed estates in southeast England are not just swarms that have escaped from apiaries and potentially represent additional genetic variation that can be used in beekeeping.

Honey bees are frequently exposed to multiple stressors in natural habitats, such as pesticides and parasites, which may potentially interact and lead to synergistic effects. Tropilaelaps mercedesae is an ectoparasitic mite that severely affects Apis mellifera, feeding on hemolymph and fat bodies of honey bee larvae and pupae, and carrying honey bee viruses. Chlorantraniliprole, a diamide insecticide widely used in agricultural production, poses potential long-term risks to bee health. In this study, we investigated the combined impacts of T. mercedesae and chlorantraniliprole on Apis mellifera. Co-exposure to T. mercedesae and chlorantraniliprole resulted in a synergistic effect, significantly reducing the survival of honey bees, while increasing the activities of oxidative stress-related enzymes, including catalase, peroxidase, and superoxide dismutase. In addition, the expression levels of abaecin and defensin 1 were suppressed, whereas vitellogenin was significantly upregulated. These findings deepen our understanding of how biotic and abiotic stressors interact to affect honey bees and provide valuable insights for developing more effective strategies for their conservation.

In most landscapes, male honey bees (Apis mellifera L.) aggregate on their mating flights in perennial aerial sites known as “drone congregation areas” (DCAs). It is widely believed that DCAs are the locations where mating occurs. Surprisingly however, that role has never been objectively evaluated. What is the role of DCAs and where do honey bees mate? Several people have observed queens and drones mating in DCAs; however those sightings are biased because observers spend most of their time at DCAs. Contradictory evidence comes from (i) matings occasionally observed outside of DCAs and (ii) the absence of DCAs in featureless landscapes. Nearly all studies have relied on the aerial presentation of a queen or her sex pheromone to attract drones and locate congregations, thereby potentially interfering with drone behavior. An alternative view from radar tracking suggests that DCAs may be reorientation points as drones travel along flyways. We currently have no objective information on where matings occur because we have been unable to track queens on their mating flights. However, a review of the literature indicates that most authors now accept that DCAs are the primary (or only) mating sites despite the lack of direct supporting evidence. Collectively, research indicates that the distribution of drones across landscapes is influenced by landmarks, topography, drone abundance, weather, and possibly pheromones from drones and magnetic anomalies. Experiments to test the importance of these factors should be conducted in a variety of landscapes. Ultimately, long-range tracking of queens and drones in various landscapes will reveal mating locations and hopefully improve our ability to influence natural matings of queens with desired drones.

Understanding the impact of environmental stressors on reproductive health in insect pollinators is critical to addressing global biodiversity and food security challenges. Although artificial intelligence (AI) methods are increasingly applied to biological data, their use in modeling insect reproductive impairments remains limited. Here, we show that machine learning can reveal biologically meaningful fertility patterns in male (drone) honey bees (Apis mellifera) and enable interpretable predictions of pesticide-induced reproductive impairments. Using an integrated machine learning framework, we characterized spermatozoa quality in A. mellifera drones exposed to neonicotinoid pesticides. K-means clustering identified three distinct spermatozoa quality profiles (low, mid, high), which were validated against reproductive benchmarks and predicted with 96% accuracy using the Extreme Gradient Boosting (XGBoost) algorithm. SHapley Additive exPlanations (SHAP) analysis revealed live spermatozoa count as the most decisive predictor, underscoring the interpretability and biological relevance of the model. Our findings demonstrate that explainable AI can model pesticide-induced changes in male insect fertility, providing a scalable tool for ecotoxicological risk assessments as well as applications in honey bee queen breeding programs.

Foragers at a resource patch can use information provided by visual and olfactory cues from other individuals to identify a high-quality resource. These cues can elicit either local enhancement or local inhibition behaviors. Both of these foraging behaviors are commonly observed among social insects, and particularly bees who frequently encounter other con- or heterospecific bees on flowers while foraging. The conditions that lead foragers to show these behaviors are contextual, and it has been difficult to draw general conclusions about the behaviors of different species without a quantitative analysis. We used a meta-analysis and vote count to synthesize literature on foraging bee behavior to test if bees more often show local enhancement or local inhibition and what circumstances lead to these two different foraging behaviors. Both our meta-analysis and vote count showed that, overall, foraging bees prefer to land on occupied flowers (local enhancement). Based on our vote count, we found that bees were more likely to show local enhancement when they were naïve, when the visual cue was from a conspecific, when experimental flowers were fake, or when the experiment happened in the lab. In comparison, local inhibition was more likely when the visual cue was a heterospecific bee, the experiment used a crushed bee, or when experimental flowers were real. Our meta-analysis provides a foundation to understand broad-scale patterns of local enhancement or local inhibition in bees. Understanding these behaviors is important because they can have contrasting effects on pollination and plant reproduction.