Apidologie最新文献

Social interactions with heterospecifics can yield important insights into the flexibility of behaviour and the role of learning in communication. Recently, the honeybee dance, a unique symbolic communication system to communicate positions in space, has been shown to involve learning. We asked if this communication system could potentially be learned by members of a species not normally using this communication system, the bumblebee(Bombus terrestris)—indicating that learning might have been at the origins of dance communication. We used mixed-species colonies of bumblebees and honeybees (Apis millefera) to investigate how the readiness to first establish contact with dancers might develop in uninformed bumblebee foragers. Over a month of observations, we recorded and classified a series of behavioural patterns in newly emerged honeybees introduced into queenright bumblebee colonies. A small subset of the introduced honeybees was able to establish in the nests and displayed their typical behavioural patterns, including homing, dance communication, trophallaxis, and social grooming. Remarkably, grooming and trophallaxis were also displayed to heterospecifics, and bumblebees accepted both, including food offered through trophallaxis, even though this behaviour is not normally used by bumblebees. However, bumblebees never attended honeybees’ waggle dances. Our results contribute to insights about bee social behaviour and cognition by providing a fascinating example of the adaptive use and modification of innate behaviour.

The quality of the queen is crucial for the survival and growth of honey bee colonies. There have been studies related to raising queens with excellent performance since the invention of artificial queen rearing technologies. However, relatively few studies have been undertaken that evaluate the relationship between queen quality and queen morphology and the expression level of reproduction-related genes using different-aged brood in artificial queen rearing practices of Eastern honey bees (Apis cerana). Therefore, we transferred eggs, 1-day-old larvae, 2-day-old larvae, and 3-day-old larvae to queen cells to rear queens until the queen emerged. We measured 12 indicators (the acceptance rate, birth weight, length, caliber and maximum diameter of queen cells, thorax length, width and weight, head width, wing length and width, and number of ovarian tubes). Moreover, the relative expression levels of Hexamerin, Vitellogenin, and Transferrin were measured using fat bodies and ovaries dissected from the newly emerged virgin queens. The results showed that queens reared from eggs exhibited the best morphological indexes and occupied the most abundant reproductive related gene expression level. Parameter values for queen from 1-day-old larvae were significantly higher than those for queens from 2-day-old larvae and 3-day-old larvae, and there was no significant difference between values for queens from 2-day-old larvae and 3-day-old larvae in most data, except for the relative gene expression. In conclusion, as the age of the brood increased, the quality of the queen bees declined. Rearing queens from fertilized eggs are far more likely to yield a better outcome for queen performance and colony function. This study provides data support for raising high-quality queens of Apis cerana, which would be benefit for the protection and better utilization of our native honey bee species.

Despite the significant contribution of stingless bees to pollination and conservation of the environment, information on their effectiveness as pollinators is insufficient. Therefore, we tested their effectiveness using watermelon, which is one of the most economically significant global food crops in terms of production volume and production value. Our study aimed at determining how bee body size, visitation rate, and bee-flower size matching ratio affect pollen deposition. We measured pollen deposition in combination with the morphometrics of 30 bees each and measurements of 30 corresponding flowers they visited. We calculated the bee-flower size matching ratio, the relationship between the bee size, and the flower measurement to gauge the effectiveness of each bee species on pollen deposition and distribution among the three watermelon stigmatic lobes. Our findings elaborate on how the different sizes of various bee parts majorly impacted the amount of pollen deposited. Besides, the number of visits, probing time, and bee behavior when handling the flower also played a role. Bees with a size matching ratio approaching 1 deposited more pollen on a single visit. However, pollen distribution highly depended on the number of visits. Among the stingless bee species, Meliponula ferruginea was the best performer. Though the honey bee species Apis mellifera was the best pollen depositor, its performance was almost similar to that of M. ferruginea. In fact, upon a single flower visit, M. ferruginea performed better than A. mellifera. Based on our findings, it can be concluded that stingless bees, particularly M. ferruginea, are effective pollinators of watermelon flowers. Furthermore, traits like probing time, multiple visits, or frequent visitation are not enough to gauge pollinator effectiveness, but there is also a need to include other traits like the size matching ratio between the bee body and flower head.

Nectar composition is an important driver of insect attractiveness. Although bumblebees prefer sucrose-rich nectar, they were found to be the main pollinators of Gentiana lutea, whose nectar is low on sucrose. Therefore, we tested the hypothesis that bumblebees are attracted to the amino acids proline and β-alanine, which are both naturally occurring at high concentrations in the nectar of G. lutea. We analysed the solution consumption and survival of Bombus terrestris L. (Hymenoptera: Apidae) workers fed with artificial nectars enriched with proline, β-alanine or both, at natural and twice the natural concentrations. We found that consumption of nectar enriched with proline at twice the natural concentration was strongly positively correlated with bumblebee weight. However, when adjusting for individual weight, we found that this solution was the least consumed, suggesting the presence of a regulatory mechanism of proline intake to reduce negative effects on survival. We did not find any direct effect of β-alanine on consumption, although our findings suggest a potential interplay between proline and β-alanine in the regulation of proline intake. Bumblebee survival was not affected by any nectar composition. These results suggest that the high visitation rate to flowers of G. lutea by bumblebees observed in natural populations can be partially related to its nectar amino acidic composition, and that protein and non-protein amino acids can affect pollinator preference and foraging behaviour.

In the coming decades, the human population will grow and demand more food. Therefore, agricultural practices are expected to be intensified. Among these practices is pesticide application. However, pesticides threaten bees and, thus, crop pollination, ultimately jeopardizing our own food security. This dilemma makes precisely quantifying the magnitude of these threats urgent, so we can improve our agricultural management practices. By conducting a systematic review followed by a meta-analysis, we estimated the effect sizes of pesticide application on bees and their crop pollination service. Our results show that pesticides reduce bee survival almost five times. Even when bees survive, sublethal effects can impair crop pollination. The consequences for bee communities and their crop pollination service might not be immediately evident but can be magnified in the long-term. Finally, we conclude that conserving the vegetation surrounding crops and minimizing pesticide use are key to protecting bees and ensuring crop pollination. Moreover, the adoption of integrated pest management (IPM) protocols can ultimately contribute to solving this problem and achieving UN’s sustainable Development Goal 2 (Zero Hunger).

Plebeia is a taxonomically complex genus of stingless bees characterized by remarkable interspecific morphological similarity. On the other hand, cytogenetic data have been useful to resolve taxonomic uncertainties and to infer the diversification processes. Therefore, the goal of this study was to provide a karyotypic analyses in five nominal taxa of Plebeia from northeastern Brazil: P. droryana Friese (Természetrajzi Füzetek kiadja a Magyar nemzeti Muzeum 23:381–394, 1900), P. cf. mosquito Smith 1863, Plebeia aff. droryana 1, Plebeia aff. droryana 2, and Plebeia aff. fravocincta based on traditional and molecular cytogenetic methods to test their applicability in cytotaxonomy and to understand the karyoevolutionary processes in these bees. All species shared a chromosomal number of 2n = 34, except for some individuals of Plebeia aff. flavocincta that presented up to two small and heterochromatic B chromosomes. Species-specific karyotype formulae were observed while the heterochromatin segments were mainly distributed on short arms and pericentromeric regions of most chromosomes, including subtle C-banding differences in each species. The 18S rDNA sites were terminally located on pair 3 of P. droryana, P. cf. mosquito, Plebeia aff. droryana 2, and Plebeia aff. droryana 1, and on the first metacentric pair in Plebeia aff. flavocincta. These data reinforced the efficiency of cytogenetics as an informative tool to discriminate Plebeia species. The present data suggest that structural rearrangements such as inversions and duplications/deletions of heterochromatin and ribosomal clusters are the main drivers of karyotypic evolution in Plebeia.

In the darkness of their nests, most social insect species communicate relying on chemical, tactile, electrical and mechanical signals. In honeybees, vibrational signals play a role not only in worker communication but also in communication among virgin queens in the process of swarming. Whereas the sensitivity to vibrations has been well studied in worker bees, vibrational sensitivity of queens and drones has never been investigated. We therefore studied the sensitivity to vibrations comparatively in workers, virgin and laying queens and in drones, focusing on the frequency range mainly used by virgin queens (350–500 Hz). Bees were tested behaviorally for responses to pulses of substrate borne vibrations in arenas placed on vibrational exciters. Vibrational amplitudes were measured using (LDV-calibrated) accelerometers. Real stimuli and sham stimuli were presented in a pseudorandom order. The threshold was defined as the lowest tested amplitude at which significantly more behavioral reactions were shown to real stimuli than to sham stimuli. Workers and virgin queens respond to amplitudes down to 0.25 m/s². The thresholds of laying queens are substantially higher and they respond to minimum amplitudes of 0.55 m/s². Drones show responses to amplitudes down to 0.6 m/s². We conclude that sex and caste have effects on vibrational sensitivity in honeybees: virgin queens are significantly more sensitive than laying queens, indicating that a high sensitivity is crucial for survival during the process of swarming; workers are likewise highly sensitive to execute efficient everyday work; drones are significantly the least sensitive.

Our insights into the responses of immature stages of vernal solitary bees to the thermal challenges of spring weather mostly come from studies of cavity-nesting megachilid bees in constant temperature incubators. Most of these studies reported either the average timing of adult emergence or the general pace of immature development. In this study, we tracked the longevity and developmental fates of eggs laid by nearly 200 female Osmia lignaria (Hymenoptera: Megachilidae) occupying observation nests set outdoors in a nature preserve. In the spring of 2022, the nesting population was challenged by a prolonged period of unseasonably chilly wet weather. As a consequence, fewer nest cells were provisioned, and hatching among the 2416 eggs was delayed for as much as a month. Surprisingly, these delays incurred no ill-effects on either egg survival or subsequent larval development, both of which were comparable to the much warmer spring of 2021 (3630 eggs). The population’s 33% reproductive shortfall in 2022 was instead attributable to limited hours warm enough for flight and foraging, in part evidenced by the paucity of multi-cell days. Eggs and larvae of this bee, and probably other vernal solitary bees, readily tolerate prolonged episodes of cold springtime weather.

Bees are often exposed to pesticide residues during their foraging trips in agricultural landscapes. The analysis of in-hive stored pollen reflects the spectrum of visited plants and can be almost used to link the exposure to pesticides.In the current study, bee bread samples were collected in May and July from 17 sites located in southern Slovakia. Samples were analysed using a multi-residue pesticide analysis method for a broad spectrum of active substances and microscopic for pollen identification.Our results revealed a bee bread contamination with 19 different active substances, with fungicides being predominant. Sixteen of them are authorized in the EU, but chlorpyrifos, chlorpyrifos-methyl, and chloridazon are not. The highest concentrations for pendimethalin (1400 µg/kg), fluazifop-butyl (640 µg/kg), fenpropidin (520 µg/kg), fluopyram (130 µg/kg), and difenoconazole (95 µg/kg) were detected. The total residue load in bee bread sampled in the early season (May) was significantly higher than in the late season (July). The mean residue load of insecticides analysed in July comprised 46% of May’s load, which is alarming due to the importance of bee bread in the diet for winter-rearing bees. Moreover, results from both sampling periods showed that fungicides were positively associated with plant families Apiaceae and Papaveraceae and herbicides with Aceraceae, Salicaceae, and Brassica-type/Brassicaceae.Hence, bee bread can be considered a suitable matrix and a good bio-indicator reflecting honey bee exposure to pesticides over the season.

Bees are crucial pollinators in terrestrial ecosystems, responsible for 80% of insect-driven pollination and playing a vital role in the pollination of 75% of crops. The honey bee, Apis mellifera, is not only used in honey production but also serves as a pollinator in agriculture. However, A. mellifera faces various challenges, including exposure to pathogens such as the Microsporidia Nosema ceranae, which has been linked to decreased crop yields and colony losses. Nosema ceranae spores infect adult honey bees by penetrating the midgut lumen and invading the cytoplasm of epithelial cells, completing their life cycle. However, the midgut possesses a protective mechanical barrier called the peritrophic matrix, composed of chitin and proteins, which prevents epithelial infection. Nevertheless, N. ceranae overcomes this primary defense mechanism, though the specific mechanisms it employs to cross the peritrophic matrix and reach the midgut epithelium are not yet well understood. This study aimed to investigate the potential role of the predicted endochitinase from N. ceranae to infect bees. We tested the hypothesis that inhibiting the expression of N. ceranae endochitinase through RNA interference would impact the pathogen infection of A. mellifera. Bees treated with dsRNA targeting endochitinase, administered 12 and 24 h after spore inoculation, exhibited suppressed endochitinase gene expression and a decrease in the number of total and viable N. ceranae spores in the midgut. These results indicate that inhibiting the expression of the target gene through RNA interference affects Microsporidia infection, underscoring the importance of this enzyme in the infection process.