Apidologie最新文献

Despite their importance to the ecosystem, global food production, and the beekeeping industry, honey bees are systematically threatened by multiple factors. Industrial agriculture plays an important role in such a process challenging both managed and wild bees. While the impacts of various insecticide classes on bees are well-documented, neonicotinoids are closely associated with colony losses, prompting their ban in several countries. Sulfoxaflor, a sulfoximine-based insecticide, has been proposed as a replacement for neonicotinoids like imidacloprid, targeting nicotinic acetylcholine receptors (nAChRs) through a distinct binding mechanism and allegedly posing lower risks to birds, mammals, and humans. This review systematically assesses sulfoxaflor’s effects on Apis mellifera, utilizing data from PubMed, Web of Science, Jstor, Scopus, Google Scholar, CORE, and the Directory of Open Access Journals (DOAJ) for studies published between 2019 and 2024. Nineteen studies were selected, excluding research on non-Apis bees or combined formulations. Findings revealed diverse sublethal impacts on honey bees, including metabolic, morphological, behavioral, and gene expression alterations. Even though sulfoxaflor is less toxic than neonicotinoids, it cannot be deemed a safe alternative for honey bees, especially once that many effects have been reported in both classes of pesticides.

Honeybees communicate the locations of profitable resources using waggle dances. Researchers have used two manual dance decoding methods to infer the spatial foraging patterns of the bees. The ‘waggle run method’ infers foraging distance from waggle duration, representing the actual distance signal of the bees, and the ‘circuit method’ infers foraging distance from the duration of complete dance circuits, including both waggle and return phases. The circuit method enables decoding dances by real-time observation and is likely quicker, but it might give inaccurate distance estimates due to variations in the return phases. Here, we decoded 200 natural waggle dances from four Apis mellifera colonies using both methods to test how well inferences about foraging locations would match and compared the time required for dance decoding. We found a high linear correlation between foraging distances inferred from waggle duration and circuit duration (R², 0.793). However, the circuit method systematically overestimated foraging distances by about 86 m. Both methods provided similar results with respect to relative differences in spatial foraging patterns between the four test colonies. Decoding the dances using the circuit method was three to four times faster than the waggle run method (2 versus 7.3 min per dance). We conclude that the circuit method can be used for many research questions that require manual dance decoding to minimize time costs. However, when aiming to maximize the accuracy of inferred foraging locations, systematic errors of the circuit method should be accounted for, or the waggle run method should be used.

The global decline of bees has raised significant concerns due to their crucial role in agroecosystems, rendering their diminishment a potential predisposing factor for a worldwide crisis in the agri-food sector and ecosystems. The use of pesticides, such as neonicotinoids, can impact non-target organisms, including bees. This study aimed to evaluate the gene expression in the heads of Apis mellifera bees in the forager phase. The analysis was conducted by examining their transcriptome to assess the effects of the neonicotinoid imidacloprid through contact bioassays, administered at both lethal and sublethal doses. The results revealed differential gene expression after 1 and 4 h of imidacloprid exposure. Differentially expressed genes were categorized based on gene ontology, revealing alterations in critical biological processes, molecular functions, and cellular components. These changes were associated with immune response, stress, neurotoxicity, and other vital functions. The study highlights the importance of considering sublethal pesticide effects and their potential long-term consequences on bee populations and ecosystem functioning.

Graphical Abstract

Commercial bumblebee colonies are routinely used for crop pollination in greenhouses and are increasingly introduced into orchards as well. Bumblebee spillover to natural habitats near the orchards may interfere with local wild bees and impact the pollination of non-crop plants. Concurrently, foraging in natural habitats may diversify the bumblebees’ diets and improve colony development. To evaluate these potential effects, we placed commercial Bombus terrestris colonies in blooming Rosaceae orchards, 25–125 m away from the margins. We recorded the colonies’ mass gain, population sizes, composition of stored pollen, and temperature regulation. We monitored bee activity, and seed sets of the non-crop plant Eruca sativa, along transects in a semi-natural shrubland up to 100 m away from the orchards, with managed bumblebees either present or absent. Rosaceae pollen comprised ~ 1/3 of the colonies’ pollen stores at all distances from the orchard margins. Colonies placed closest to the margins showed prolonged development, produced fewer reproductive individuals, and had poorer thermoregulation than colonies closer to the orchards’ center. Possibly, abiotic stressors inhibited the bumblebees’ development near orchard borders. Wild bees were as active during the colonies’ deployment as after their removal. E. sativa’s seed sets decreased after bumblebee removal, but similar declines also occurred near a control orchard without managed bumblebees. Altogether, we found no short-term spillover effects of managed bumblebees on nearby plant-bee communities during the orchards’ two-week flowering. The colonies’ prompt removal after blooming can reduce longer-term ecological risks associated with managed bumblebees.

Vespula germanica wasps are natural predators of Apis mellifera bees and can also be problematic for beekeeping. We evaluated the variation in agonistic interactions between V. germanica and A. mellifera hives at two times of the day: noon, when bees exhibited activity at the hive entrance, and early in the morning, when they were not active. Aggressive interactions were 13 times higher during the morning when bees were less active. The most frequent interaction at noon involved wasps approaching the hive, while in the morning, it was frequent to observe wasps entering the hive. We also analyzed the effectiveness of lavender oil as a repellent and found it reduced aggressive interactions by approximately 75% immediately after application, with the effect lasting 48 h. The reapplication of lavender oil at the hive entrance extended its effect for 24 h. We concluded that bee activity, measured as bee traffic at the hive entrance, could be an indicator of susceptibility to wasp attacks and a key factor in this predator‒prey interaction, making hives more susceptible to V. germanica attacks in the morning. Similarly, lavender oil acts as a repellent agent, reducing the impact of wasps in the short term.

Positive phototaxis, an innate attraction to light, is crucial for bees’ navigation and escape behaviours. With the migration of bee-pollinated crops to greenhouses, alterations in light and temperature within these environments may influence bees’ phototactic responses. We evaluated how the attenuation of UV and green light affected the proportion and latency of the phototactic orientation of stingless bees within a Y-shaped maze, in which sunlight was filtered by different materials at its two edges. We found that three species of stingless bees (Melipona quadrifasciata, Scaptotrigona cf. postica, and Frieseomelitta varia) were more frequently attracted to the edge with a higher incidence of solar UV light and exhibited shorter orientation latencies than to the opposite edge, which had virtually no UV transmittance and lower green light transmittance. Under conditions of low UV light at both ends of the maze, neither a higher proportion of green light nor greater total light intensity influenced the phototactic orientation of the three species towards a particular maze arm. These findings indicate that UV light is a key component of the phototactic response in the tropical bee species studied and should be considered when employing these species for pollination services in protected environments with low UV incidence.

In bumblebees, successful colony establishment typically requires mating before diapause, as unmated queens were previously thought to have limited reproductive potential. However, the possibility of postdiapause mating has remained largely unexplored. This study investigated the reproductive success of Bombus terrestris queens by reversing the typical sequence of mating and diapause under laboratory conditions. Gynes underwent diapause for 4 or 7 months before mating with unrelated males. The results revealed high survival rates during diapause, with no significant differences between the two diapause durations. Postdiapause mating success was also high, with 82.6% of queens in the 4-month group and 77.7% in the 7-month group successfully mating. The length of diapause appeared to slightly affect the ability of nests to produce new gynes, but the difference was not statistically significant. These findings challenge the assumption that unmated gynes are inevitably constrained in their reproductive potential. If confirmed in other species, this strategy could provide a valuable tool for conservation breeding programs.

Tropilaelaps mercedesae is a parasitic mite species that negatively affects the health of Apis mellifera colonies. Recent reports show that it is spreading westwards, through Central Asia into Europe. Several field and laboratory methods have been proposed to detect Tropilaelaps spp. in A. mellifera colonies; however, most of them are recognised to be either laborious, costly or ineffective for detecting the mites, and some are even destructive to the colony. Here, we introduce a novel method for detecting and monitoring T. mercedesae based on the mite's characteristic biology (reduced feeding as bee pupae mature, brief dispersal phase on adult bees and agility) and the use of wax strips for decapping sealed brood area. Sealed worker brood cells at the development stage of white to purple-eyed pupae are swiftly decapped with wax strips to observe and count surfacing adult mites. The results from our study show supporting evidence of over 90% detection efficacy and brood survival, and ease of application. Therefore, we recommend the novel ‘Rapid brood decapping’ method as a reliable tool for detecting and monitoring T. mercedesae infestation. This method is suitable for beekeeping and research settings, being less invasive and stressful for colonies compared to other existing methods, cost-effective and quick.