Apidologie最新文献

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.

Large hive beetles (Oplostomus fuligineus, LHB) have long been recognized as significant pests of honey bee colonies, particularly across the African continent. Although LHBS are native to Sub-Saharan Africa, they have recently been recorded in North Africa, feeding primarily on young bee larvae within colonies, which leads to severe damage, especially in weaker colonies. In 2021, Abou-Shaara et al. predicted a high risk of LHB invasion into the North African and South Europe regions due to temperature variations. As a result, we performed a follow-up study based on a survey to assess the spread of LHB across the Arabian region. The questionnaire contained essential items from the global COLOSS surveys. During a two-month survey in 2024, 54 beekeepers from 11 Arabian countries responded, with Egypt, Algeria, Saudi Arabia, and Yemen contributing the most data. The infestation rate was highest in countries along the Mediterranean and the Red Sea, including Algeria, Tunisia, Egypt, Palestine, Saudi Arabia, and Yemen, indicating that LHB may favor coastal weather conditions. Nearly all beekeepers notice significant hive beetle infestations in May, June, and July. This study is the first thorough survey undertaken in the Arabian region, establishing the first recorded occurrence of LHB, confirming earlier predictions, and emphasizing the critical need for additional research and management strategies.

In honey bees, drones’ flight ability is crucial for their mating success. In this study, we assessed the flight ability of drones from three age cohorts (1–3 weeks old) by flight mill and subsequently examined their sexual development and status, viral infection by deformed wing viruses type A and B (DWV-A, DWV-B) and Israeli acute paralysis virus (IAPV) and expression of six immune genes by RT-qPCR. Sexually matured drones flew longer distances compared to immature drones. Infections of DWV-A and IAPV were common in drones, but their impact on drone flight differed. Flight distance and speed were negatively correlated with loads of IAPV and DWV-B, respectively, in 14- to 15-day-old drones, but not in 7 days old. Flight speed was negatively correlated with the expression of protein lethal 2 (Pl2) and peptidoglycan recognition protein S2 (PGRP-S2) in 14- to 15-day-old drones. These findings suggest trade-off between a drone’s flight performance and their immunity and/or the impact of virus infection on drones’ flight ability.

Parasitic mites of the genus Varroa pose a serious threat to global apiculture. Host switches from native to introduced Apis species have occurred in multiple Varroa species, in some cases with devastating results. Additional host shifts and hybridisation among mite species and mite lineages on different hosts represent significant risks for apiculture and natural ecosystems. Quantifying this risk is thus an essential step toward management. The risk of hybridization among mite lineages on different hosts is likely to be at its highest in eastern Asia, where multiple host and mite lineages occur sympatrically. The available evidence, however, is somewhat contradictory, suggesting gene flow is occurring in some localities, but limited or absent in others. In this study, we elucidate the relationships between Varroa mites collected from A. mellifera and A. cerana in Vietnam, a region of high overlap of mite species and hosts, using a combination of genome-wide SNPs and mitochondrial sequence data. Our results indicate an absence of any new host shifts and a lack of gene flow across host species and between mite species, despite considerable overlap in mite and host species ranges. This confirms the findings of several earlier studies in this area but contrasts with evidence of hybridization in other regions, suggesting regional differences in the potential for gene flow between host/mite combinations. Nonetheless, we suggest this area remains one of high risk, because of (i) considerable overlap of mite lineages which elsewhere have been shown capable of interbreeding, (ii) evidence we find of human-mediated long-range dispersal events, which increase the chance of interaction among different mite lineages, and (iii) the persistent threat of secondary factors such as disease transmission, which may be facilitated by both of the factors above.

The yellow-legged hornet is an invasive species that has been established in Galicia, northwestern Spain, since 2012. This hornet shows an increased level of invasiveness, which allows it to grow and spread rapidly throughout the territory. Furthermore, the climatic characteristics of the region have contributed to their establishment, with beekeeping being the most affected sector. The study aimed to monitor the predatory behavior of Vespa velutina and its correlation with environmental conditions, as well as the honey bee survival risk of the predation. Temperatures ranging from 17 to 26 °C were the most suitable for observing the higher number of hornets. The hornets were observed in front of the colonies for 16 h a day for 11 months. The presence of five or more hornets posed a risk to the survival of the honey bee colonies. Beekeepers should manage their colonies with artificial feeding and use control methods for survival against V. velutina.

The greater wax moth, Galleria mellonella L., is a noxious pest in beekeeping, causing huge economic loss by weakening the colonies and reducing honey production. Present wax moth management techniques are ineffective, potentially leading to the loss of bee colonies. Utilization of Bacillus thuringiensis is emerging as a sustainable practice for managing G. mellonella. Hence, in the present study, five B. thuringiensis isolates were isolated from soil samples and a G. mellonella cadaver, and all the isolates were characterized for morphological and molecular characteristics. The in vitro bioassay studies showed strain NBAIR BtVGa2 isolated from G. mellonella cadaver is very effective against wax moth second instar larvae with a lower LC₅₀ value of 5.40 μg/mL as compared to other B. thuringiensis strains. Biosafety studies showed NBAIR BtVGa2 is 97% safer for larvae and adults of honeybees since the strain does not consist of any hymenopteran-specific insecticidal genes. The plasmid sequencing of NBAIR BtVGa2 generated 891,714 paired-end reads with 34.13% GC content and a 0.89-Mbp genome size, along with 903 protein-coding genes with a single tRNA. The plasmid profiling of NBAIR BtVGa2 identified many insecticidal genes, viz., cry1Ac5, cry2Aa9, Zwa5A, Zwa5B, Zwa6, mpp46Ab1, and vpb4Ca1, in which mpp46Ab1 and vpb4Ca1 were novel genes with only 33.61 and 66.42% sequence similarity, respectively. The presence of these genes was validated by PCR amplification, and the structure of these insecticidal genes has also been predicted. Overall, the study identified a highly efficient strain of B. thuringiensis for the biological management of G. mellonella. The study also deciphered molecular mechanisms behind the efficiency of the NBAIR BtVGa2 strain. The study opened the path for the biological method of management of G. mellonella considering the safety of honeybees.

Graphical Abstract

Depicting molecular mechanism behind biocontrol potential of Bacillus thuringiensis strain NBAIR BtVGa2