Apidologie最新文献

Thiamethoxam (TMX) is one of the most widely used neonicotinoid insecticides. However, it is unclear how TMX alters the flower-visiting behavior and seed production of Apis cerana in sunflowers. We conducted cage experiments to study the impact of chronic exposure (10 days) to TMX at sublethal concentrations of 2.4 μg/kg and 10 μg/kg on the number of flower visits per minute, seed setting percentage, 100-seed weight, and seed yield in sunflowers. Bees treated with TMX demonstrated a significantly lower number of flower visits per minute compared with the control group. Although we did not observe a significant difference in yield parameters between TMX treatments and the control group, a positive correlation was observed between yield and the bees’ flower visitation rate. Our study highlights the concern that exposure to field-level concentrations of TMX could pose a threat to the pollination services provided by A. cerana for other crops and wildflowers.

We observed this behaviour, previously studied only in North America and as a rare occurrence, on each of the three visits, one per year, we made to the same site, in Italy. Honey bees Apis mellifera L. preferred collecting pollen from red-tailed bumble bees Bombus lapidarius L. than directly from flowers of the woolly thistle Cirsium eriophorum (L.). In another site, which equally had this thistle species as the only plant in bloom, but fewer bumble bees, honey and bumble bees foraged concomitantly on the same flowers avoiding interspecific contacts. In both sites, the honey bees showed easier foraging in the presence of male, than of less tolerant worker, bumble bees. In a third site, the honey bees preferred foraging independently on the smaller flowers of the Tyrol thistle Centaurea nigrescens Willd., while the bumble bees preferred the woolly thistle. Therefore, when plants offer few foraging choices, honey bees may visit less preferred large composite flowers where a crowd of bumble bees hampers their usual foraging mode, but little-reactive males offer pollen collection from their furry bodies, to which honey bees specialize.

Human sewage can introduce pollutants into food webs and threaten ecosystem integrity. Among the many sewage-associated pollutants, pharmaceuticals and personal care products (PPCPs) are consistent indicators of sewage in ecosystems and can also cause potent ecological consequences, even at minute concentrations (e.g., ng/L). Despite increased study over the past three decades, PPCPs in terrestrial ecosystems have been less studied than those in aquatic ecosystems. To evaluate PPCP prevalence and drivers in a terrestrial ecosystem, we analyzed managed and native bees collected from agroecosystems in Washington State (USA) for PPCPs. Caffeine, paraxanthine, cotinine, and acetaminophen were detected in all three evaluated taxa (Bombus vosnesenskii, Agapostemon texanus, and Apis mellifera), with B. vosnesenskii and A. texanus having a higher probability of PPCP detection relative to A. mellifera. The probability of PPCP presence in all three taxa increased in landscapes with more human development and greater plant abundance, with significant but negative interactions among these factors. These results suggest that human activity, availability of resources, and species-specific pollinator traits affect the introduction and mobilization of PPCPs in terrestrial ecosystems. Consequently, monitoring PPCPs and their ecological responses in terrestrial ecosystems creates opportunities to synthesize effects of sewage pollution across terrestrial and aquatic ecosystem types and organisms.

The ecological interactions of biota with natural ecosystems are still poorly understood. In Subtropical Dry forests, several stingless bees utilize cavities within trees for nesting. Due to their lack of morphological traits for creating these cavities, bees rely on other mechanisms to access and utilize hollow spaces. In the Argentinian Dry Chaco region, we set two main objectives: (1) Determine the richness of cavity-nesting bees and describe the characteristics of trees selected as substrates, and (2) identify the mechanisms employed by stingless bees in selecting trees with hollows. Observational records were used to identify bee-nesting sites, while standard vegetation inventory was conducted to assess preference. Structural equation models were employed to establish the selection mechanisms of tree species for nesting. We found 139 nests belonging to three species: Plebeia catamarcensis (n = 118), Plebeia molesta (n = 14), and Lestrimelitta (L.) chacoana (n = 2). Stingless bees, particularly smaller species like P. catamarcensis, specifically select Neltuma trees for nest installation. This preference is attributed to the presence of galleries and hollows within the heartwood, created by the larvae of Criodion angustatum beetle. Although the larval action may harm the mechanical structure of the trees and hasten their demise, it simultaneously creates suitable hollow spaces for the establishment of bee colonies. Further investigations into these species interactions within the forest are necessary to enhance management practices in this threatened ecosystem, recognizing the important ecological role of Neltuma genus as crucial for ensuring the availability of nesting substrates for these native stingless bees.

Bumblebees have become model organisms for cognitive ecology and social learning. Quantifying the foraging behavior of free-flying bees, however, remains a methodological challenge. We describe and provide the code for a method of studying bee free flying foraging behavior using the open source neural-network based markerless tracking software DeepLabCut. From videos of bees foraging in an arena we trained a neural network to accurately track the position of each bee. We then used this approach to study foraging behavior and show that the ratio between flying time and flower visiting time decreases over repeated foraging bouts, indicating increasing efficiency of bee foraging behavior with experience. Visit durations, a laborious metric to measure by hand, were significantly shorter on flowers that had previously been visited. This experiment illustrates the usefulness of DeepLabCut for objective quantification of behavior, and in this case study shows that previous experience increases bee foraging efficiency.

Native bees are vital pollinators in the Neotropical Region and can serve as bioindicators for maintaining floral diversity in natural environments. However, the use of pesticides, specifically neonicotinoids, in agroecosystems has led to a decline in these pollinating organisms. This study aimed to evaluate the topical (contaminated mist) and residual (contaminated food) acute effect of the insecticide imidacloprid (IMI) on a stingless bee species (native to Brazil) with wide geographical distribution (Tetragonisca angustula) and two species restricted to certain regions (Tetragonisca fiebrigi and Tetragonisca weyrauchi) to determine LC_10–48 h and LC_50–48 h. The bees were exposed to various concentrations of IMI, in both topical and residual effect tests, and the results showed that low concentrations of the insecticide adversely affected the survival of all three species, with T. angustula being the most sensitive. The study also compared the sensitivity of the three species to the standard insecticide Dimethoate, and the results confirmed that T. angustula was the most sensitive. The findings of this study provide crucial ecotoxicological information, particularly concerning the residual effects of neonicotinoids on stingless bees. This evidence reinforces the urgent need to expand research on the effects of neonicotinoids on these important pollinators, so commonly found in nature and meliponaries. In addition, this research contributes significantly to filling the existing knowledge gap about the effects of pesticides on bee species native to Brazil, bringing to light the potential risks that these chemicals pose to the survival of these pollinators and emphasizing the urgent need for efforts of conservation in favor of these precious pollinating agents.

Estrogen-related receptors (ERRs) belong to a large class of orphan receptors in the nuclear receptor (NR) family. Bisphenol A (BPA) is known as an endocrine disruptor and xenoestrogen with a high affinity for the human estrogen-related receptor (ERRγ). Insects lack estrogen receptors (ER), and their ERR is orthologous to ERRγ. This study was intended to examine whether BPA does not affect the ovarian expression of orphan nuclear ERR in queen honey bees (Apis mellifera L.). The amERR gene was amplified by polymerase chain reaction (PCR) from the cDNA of bees. The amERR protein was harvested and purified with the recombinant vector amERR/pET-32a. Using RT-qPCR and Western blot (WB), the levels of amERR gene and protein expression in the ovaries of control and treated bees were determined. The results indicated that both 3 µg and 10 µg doses suppressed the ovarian expression of amERR, with 6H inhibition being the most significant. Furthermore, AutoDockVina was utilized for simulating molecular docking between the tertiary structure of amERR predicted by I-TASSER and BPA. It hinted that BPA could conjugate with the ligand-binding pocket (LBP) of amERR. Thus, BPA might arrest amERR activation through binding. The results showed that BPA might impact the transcription and protein expression levels of the amERR gene. It may be correlated with the potential specific binding of BPA and amERR.

Beekeeping as a staple of agriculture in Kazakhstan is believed to have emerged when external bee colonies were introduced into the country. To date, six subspecies have been distributed across commercial apiaries (Apis mellifera sossimai, A. m. carpatica, A. m. mellifera, A. m. ligustica, A. m. caucasica, and A. m. carnica). In this study, we analyzed mitochondrial DNA from 21 geographically distinct populations with diverse subspecies composition and discovered 19 unique haplotypes belonging to C and M evolutionary lineages. Analysis of 9 microsatellite loci revealed strong polymorphism, with a range of 5 to 35 alleles at each locus. The observed heterozygosity across the populations varied from 0.2892 to 0.9099, and clustering analysis only allowed differentiation of each population based on its geographical location. High degree of admixture among subspecies was identified in every population, including a potential introgression from the endemic bee A. m. pomonella. Unregulated cross-breeding for the past 50 years has laid the foundation for the promiscuous genetic nature of honeybee populations in Kazakhstan.

Managed honey bees are experiencing high rates of colony loss, in part due to widespread exposure to agrochemicals and other environmental toxins. The ability to learn about relevant environmental stimuli is an important skill necessary for foraging and navigation, although it is sometimes impaired in bees that have been exposed to toxins or other stressors. Here, we review the effects of anthropogenic toxins (which we divide into five major classes: insecticides, acaricides, biopesticides, other agrochemicals, and other toxins) on learning performance in European honey bees. We discuss the general trends of these studies, including that neurotoxic insecticides are overwhelmingly the most well-studied, and that most studies focus on acute exposure of individual, adult bees to a single toxin. Protocols for field-relevant exposure vary widely among labs, and we make suggestions to aid in the standardization of future studies. We review the relevance of learning studies for toxicological risk assessment, concluding that they are valuable tools for assessing sublethal behavioral effects of toxins. Their inclusion in risk assessment studies would be an improvement over current procedures, which focus largely on lethality.

Bees from different groups are able to make nests and complete their life cycles in flooded sites. We report the nesting of Centris aethyctera in a mangrove area subject to periodic flooding during high tide. Nests in the mangrove are submerged in salty water periodically throughout the year, including in the initial stages of nest construction and provisioning. Furthermore, this is the first report of a bee species using estuarine areas for nesting. We show the life cycle, the characteristics of the substrate, the frequency of flooding, and the rates of brood mortality. Kleptoparasitic bees attack the nests and survive until hatching simultaneously with their host. The highest brood mortality occurred during the period of nest construction and development of the first larval stages. The impermeability and resistance of the cocoon secreted by the prepupa seem to be adequate for resisting submersion. The malleability and temperature of the wet sandy-silty substrate may facilitate the construction of nests and compensate for the disadvantages of its flooding potential.