Apidologie最新文献

Only female bees actively collect pollen, which they use to provision brood. Although male bees also visit flowers for nectar and thus may passively vector pollen, the contribution of males to pollination services is poorly documented for most bee species. We investigated pollen transport by males of the Australian stingless bee Tetragonula carbonaria. We found that almost all males sampled at mating aggregations had pollen on their bodies, and that the quantity and diversity of pollen grains on males was similar to that found on nectar-foraging workers. We then assessed behavioural differences between males and workers which might influence pollen acquisition and retention. We found that both sexes behaved similarly while foraging on flowers, regularly contacting the flower’s reproductive structures. Both males and workers also groomed themselves to remove excess pollen, but in the morning males tended to have more pollen grains left on their bodies from the previous day’s foraging. This is presumably because workers (but not males) are allogroomed by their sisters in the nest and thus more efficient at removing pollen overnight. In all, our results suggest that male T. carbonaria may contribute to the pollination of a range of native plants and indicate possible sex differences in pollen transport by stingless bees. In particular, as male stingless bees remove less pollen from their bodies overnight and traverse far greater distances in their lifetimes, they may be more likely than workers to move pollen between fragmented plant communities.

Bombus terrestris are known for nesting underground. Here, we describe observations of an unusual, opportunistically built above-ground nest of buff-tailed bumblebee. The B. terrestris nest contained six workers and 14 cocoons with pupae at various stages, two empty pollen pots and nine reed tubes also used as nectar/pollen storage pots. Bombus terrestris workers used a wooden nesting box with reed tubes, which was designed as a nesting aid for solitary bees (Osmia bicornis). In our opinion, the most likely scenario is that this was an unintended consequence of removing commercial Bombus nests from the apple orchard in the middle of the day, so foragers had no place to return to and settled in the nearest possible place/shelter. This is a great example of the high flexibility of bumblebees in terms of available (anthropogenic) nesting sites and may suggest that microcolonies can also occur in nature.

Pseudohypocera kerteszi is a kleptoparasitic scuttle fly that invades meliponine bee hives, exploiting colony pollen reserves to provision its larvae. Such invasions can precipitate colony collapse, posing a significant threat to meliponiculture in Central and South America. Notably, the flies enter colonies with minimal resistance from typically aggressive guard bees, prompting questions about potential chemosensory or behavioral manipulation. To explore this, we compared the cuticular hydrocarbon (CHC) profiles of P. kerteszi with those of three co-managed meliponine bee species—Melipona scutellaris, Nannotrigona minuta, and Scaptotrigona tubiba—and conducted behavioral assays in controlled arenas and at nest entrances, using S. tubiba as a model species. The CHC profile of P. kerteszi comprises 50 compounds—including n-alkanes, unsaturated hydrocarbons, methyl-branched alkanes, and fatty acyls—with the unique presence of 8,18-heptacosadiene and 10-dotriacontene. In contrast, workers of M. scutellaris, N. minuta, and S. tubiba exhibit profiles dominated by odd-chain alkanes and alkenes, with little or no contribution from alkadienes or methyl-branched alkanes. Bioassays revealed that while S. tubiba guard bees aggressively reject non-nestmates, they tolerate adult P. kerteszi. These findings provide strong evidence against chemical mimicry, camouflage, or insignificance as primary drivers of host acceptance. Instead, the data are consistent with the hypothesis that P. kerteszi utilizes alternative mechanisms, such as physical evasion facilitated by its small size and maneuverability, to prevent the initiation of a full defensive response. This study provides the first chemical characterization of P. kerteszi and narrows the scope of potential evasion strategies, guiding future research on this kleptoparasitic system.

To unravel complex plant-pollinator interactions, it is essential to be able to obtain not only qualitative but also quantitative information about the composition of pollen carried by insects. This information can be gathered by light microscopy identification of pollen grains, but this process can be time-consuming and requires trained specialists. ITS2 metabarcoding can be a powerful tool, providing a high taxonomic resolution in identifying taxa represented in a pollen sample; however, a possible critical point of this approach may be its quantitative reliability in estimating the relative abundance of pollen taxa, especially when ITS2 is used as a single marker. The aim of this work was to test the quantitative reliability of the ITS2 metabarcoding approach in assessing the composition of pollen carried by insects. Pollen samples consisting of a limited number of grains were retrieved from different bee families collected in different environments. The NGS reads obtained by ITS2 metabarcoding were compared at the family level with the pollen grain counts obtained by light microscopy. Moreover, the proportion of NGS reads corresponding to blooming plants occurring in the sampling area was evaluated at the genus level. The results highlighted a good correlation between the relative abundances obtained with metabarcoding and microscopy, and a good accuracy of metabarcoding in providing quantitative results independently of bee taxon and pollen taxa composition. Furthermore, this study indicates that ITS2 metabarcoding can be applied when the available amount of pollen is a constraint, an important point in the perspective of an actual evaluation of plant-pollinator interactions.

Nosema ceranae, a widely distributed microsporidium, is one of the major factors contributing both to colony loss and to the impairment of Apis mellifera health. Studies on its prevalence have been limited to national levels, and have shown wide variability, probably in response to various factors, but it is unclear which represent risk factors. To address these gaps, a systematic review and meta-analysis was conducted to estimate the global and regional prevalence of N. ceranae infection in colonies and apiaries of the European honey bee, and explored associated risk factors. Following PRISMA guidance, literature searches in Web of Science, PubMed, Scopus and SciELO identified 48 cross-sectional studies meeting predefined eligibility criteria on language, design, outcome definition and reporting, with risk of bias assessed using the Newcastle–Ottawa Scale adapted for cross-sectional studies. The meta-analysis showed a combined overall prevalence of 39.52% (95%CI: 29.01; 50.51) at the colony level, with Northern America having the highest combined prevalence. At the apiary level, it was 34.93% (95%CI: 27.23; 43.00), with Europe being the region with the highest levels. Climate type explained between-study heterogeneity: tropical and temperate climates increased colony-level risk, whereas temperate and arid climates increased apiary-level risk.

Rare species of peculiar habitats are essential for conservation. This study summarizes the current knowledge on the rare, Italian endemic, high-altitude bumblebee Bombus konradini. Using historic collections, literature, and new records (2014–2025), I summarized the distribution, habitat, and plant use, and tested if areas previously predicted as suitable host the species. Recent field efforts doubled the known individuals and sites, compared to previous times, and confirmed areas only previously predicted as suitable. Climatic, topographic, and elevational features of the habitat are highlighted; the visited flowers are contextualized. As data become increasingly essential for conservation, it is crucial to provide them especially of rare, protected species: in this sense, this study offers a significant pillar for B. konradini’s conservation.

This study was aimed at determining the mating characteristics and diapause performances of queens mated with queen-born males (QMs) and worker-born males (WMs) in Bombus terrestris colonies. Using laboratory-reared colonies, mating latency, copulation duration, and queen mating preferences were analyzed for both QM and WM groups. Results showed no significant differences in mating latency and copulation duration between the two male groups. However, WMs were slightly heavier than QMs during the mating process (t = −2.02, P = 0.044). Despite these weight differences, the mating success rates of QMs and WMs were comparable, with queens showing no significant preference for either group. Additionally, the survival rates of queens during diapause were unaffected by whether they mated with QMs or WMs. This research suggests that the source of males in B. terrestris colonies does not influence mating success or queen survival, providing valuable insights for bumblebee breeding and colony management.

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.