Bumblebees (Hymenoptera, Apidae,
Bombus
) are important pollinators . Thirty-five bumblebee species belonging to 11 subgenera occur in Bulgaria according to 42 scientific papers.
In the current study ...the reported species names were updated according to the current taxonomy of the group (Williams 2019) The data about their localities in Bulgaria were systematized by geographical regions in order to summarize and facilitate the use of this information for future research. Most of the records of bumblebee species refer to the mountains Rhodopes, Rila, Western and Central Stara Planina, Vitosha and Slavyanka.
Additionally, 22 species were identified based on 553 specimens (103 queens, 180 males and 270 workers) from the Zoological collection of Sofia University (BFUS). The richest in species were the subgenera
Thoracobombus
Dalla Torre,
Psithyrus
Lepeletier and
Pyrobombus
Dalla Torre. New distribution records were shown for the Western and Eastern Stara Planina Mts, Sofia plain, Lozen Mt., Northern and Southern Black Sea coast. However, geographical regions such as Plana Mt., Ruy Mt., Verila Mt., Kraishte, Vlachina Mt., Ograzhden Mt., the Sub-Balkan Basins and the Mesta River valley have not been studied and are without any available data on bumblebees.
Pentameric ligand-gated ion channels (pLGICs) activated by the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) are expressed widely in both vertebrate and invertebrate species. One of the ...best characterised insect GABA-gated chloride channels is RDL, an abbreviation of 'resistance to dieldrin', that was originally identified by genetic screening in Drosophila melanogaster. Here we have cloned the analogous gene from the bumblebee Bombus terrestris audax (BtRDL) and examined its pharmacological properties by functional expression in Xenopus oocytes. Somewhat unexpectedly, the sensitivity of BtRDL to GABA, as measured by its apparent affinity (EC.sub.50 ), was influenced by heterologous expression conditions. This phenomenon was observed in response to alterations in the amount of cRNA injected; the length of time that oocytes were incubated before functional analysis; and by the presence or absence of a 3' untranslated region. In contrast, similar changes in expression conditions were not associated with changes in apparent affinity with RDL cloned from D. melanogaster (DmRDL). Changes in apparent affinity with BtRDL were also observed following co-expression of a chaperone protein (NACHO). Similar changes in apparent affinity were observed with an allosteric agonist (propofol) and a non-competitive antagonist (picrotoxinin), indicating that expression-depended changes are not restricted to the orthosteric agonist binding site. Interestingly, instances of expression-dependent changes in apparent affinity have been reported previously for vertebrate glycine receptors, which are also members of the pLGIC super-family. Our observations with BtRDL are consistent with previous data obtained with vertebrate glycine receptors and indicates that agonist and antagonist apparent affinity can be influenced by the level of functional expression in a variety of pLGICs.
Heatwaves are an increasingly common extreme weather event across the globe and are projected to surge in frequency and severity in the coming decades. Plant‐pollinator mutualisms are vulnerable due ...to interacting effects of extreme heat on insect pollinator foraging behaviour and their forage plants.
We designed an experiment to parse the impact of extreme heat on bumblebee foraging mediated directly through air temperature and indirectly through changes in plant rewards.
Temperatures simulating a moderate heatwave negatively impacted foraging bumblebees reducing the proportion of successful foraging bouts, foraging bout duration and plant and flower visitation and indirect stress through reduced nectar production that limited foraging bout duration.
Our experimental results provide a mechanistic link between climate, plants and pollinators and suggest in situ conditions from heatwaves could have profound negative consequences for bumblebee colony persistence and maintenance of pollination services.
Read the free Plain Language Summary for this article on the Journal blog.
Read the free Plain Language Summary for this article on the Journal blog.
For many species, geographical ranges are expanding toward the poles in response to climate change, while remaining stable along range edges nearest the equator. Using long-term observations across ...Europe and North America over 110 years, we tested for climate change–related range shifts in bumblebee species across the full extents of their latitudinal and thermal limits and movements along elevation gradients. We found cross-continentally consistent trends in failures to track warming through time at species' northern range limits, range losses from southern range limits, and shifts to higher elevations among southern species. These effects are independent of changing land uses or pesticide applications and underscore the need to test for climate impacts at both leading and trailing latitudinal and thermal limits for species.
The study was designed to test the feasibility of using 3D-printed pollen traps for long-term monitoring of Bombus terrestris colonies' exposure to pesticide residues in pollen loads collected by ...them, along with an assessment of the resulting risks to the bumblebee's adults, larvae, and queens. Bumblebee colonies were placed in the vicinity of flowering orchards, winter oilseed rape, allotments, or home gardens for 6 weeks of the experiment. Pollen traps printed in 3D technology were installed in the hive inlets. The weight of bumblebee pollen loads obtained using pollen traps was in the range of 0.036–5.83 g. Pollen load samples were analyzed for residues of up to 261 pesticides and their metabolites by liquid and gas chromatography techniques coupled to tandem mass spectrometry (LC-MS/MS and GC-MS/MS). Residues of 18 fungicides, 12 herbicides, 6 insecticides, and an acaricide were detected. Herbicide – pendimethalin, fungicide – thiophanate-methyl, and insecticide – chlorpyrifos-ethyl were the most commonly detected pesticides. Chlorpyrifos and thiacloprid residues were detected in pollen load samples in the next year after their ban from use as plant protection products in the European Union. The risk of acute or chronic effects was assessed as negligible or low, although the chronic risk of bumblebee queens to insecticide chlorpyrifos and the acute risk of larvae exposed to acaricide fenpyroximate could be interpreted as moderate. The risk of sublethal effects related to chronic exposure of adult bumblebees and queens to pollen loads contaminated by chlorpyrifos-ethyl and cypermethrin cannot be excluded. The risk of chronic toxicity or sublethal effects may be particularly relevant for bumblebee queens, especially during their foraging in the initial period of establishing a new colony.
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•3D-printed pollen traps used to collect pollen from the Bombus terrestris colonies.•261 pesticides and their metabolites monitored in pollen loads.•Up to nearly 6 g of bumblebee pollen loads collected in a single day by pollen trap.•Exposure and risk assessment for bumblebee adults, larvae, and queens.•Generally low or negligible risk for bumblebees was estimated.
Continuous availability of food resources, such as pollen, is vital for many insects that provide pollination and pest control services to agriculture. However, there is a lack of knowledge about the ...shared or complementary use of floral resources by such species, which hampers more effective landscape management to simultaneously promote them in agroecosystems.
Here, we simultaneously quantified pollen use by a bumblebee (Bombus terrestris) and a mason bee (Osmia bicornis), two bee species recognized as important crop pollinators, as well as a lacewing (Chrysoperla carnea) and a ladybeetle species (Harmonia axyridis), both common predators of crop aphids, throughout the season in 23 agricultural landscapes in Germany and Switzerland.
Pollen diets were more diverse and similar among C. carnea and H. axyridis compared to the two bee species, but all four species shared key pollen types early in the season such as Acer, Quercus, Salix and Prunus. All species exhibited a pronounced shift in pollen sources from primarily woody plants (mainly trees) in spring to primarily herbaceous plants in summer. The majority of pollen (overall ≥64%) came from non‐agricultural plants even in crop‐dominated landscapes.
Synthesis and applications. Our results highlight the importance of trees as pollen sources for many insect species, particularly early in the season. Our findings support incentives that promote heterogeneous agricultural landscapes including both woody and herbaceous semi‐natural habitats, ensuring phenological complementarity of floral resources for insect species that can provide pollination and pest control services to agriculture. The identified key plant species can help to design and optimize agri‐environment schemes to promote these functionally important insects.
NanotransducersThe microbial‐free bumblebee is a powerful tool to explore the precise control of engineered microbiota. Nanotransducers are fabricated to regulate the engineered bacteria inside the ...bumblebee gut by two spatiotemporal means, including magneto‐thermal and photothermal. This advanced technology lays the foundation for the treatment of bumblebee intestinal parasitic diseases and the elimination of pesticide residues. More details can be found in article number 2301064 by Hao Zheng, Yuan Lu, and co‐workers.
In this work, we present black hole solutions with a cosmological constant in bumblebee gravity, which provides a mechanism for the Lorentz symmetry violation by assuming a nonzero vacuum expectation ...value for the bumblebee field. From the gravitational point of view, such solutions are spherically symmetric black holes with an effective cosmological constant and are supported by an anisotropic energy-momentum tensor, conceived of as the manifestation of the bumblebee field in the spacetime geometry. Then we calculate the shadow angular radius for the proposed black hole solution with a positive effective cosmological constant. In particular, our results are the very first relation between the bumblebee field and the shadow angular size.
The purpose of this paper is twofold. First, we introduce a geometric approach to study the circular orbit of a particle in static and spherically symmetric spacetime based on Jacobi metric. Second, ...we apply the circular orbit to study the weak gravitational deflection of null and timelike particles based on Gauss-Bonnet theorem. By this way, we obtain an expression of deflection angle and extend the study of deflection angle to asymptotically nonflat black hole spacetimes. Some black holes as lens are considered such as a static and spherically symmetric black hole in the conformal Weyl gravity and a Schwarzschild-like black hole in bumblebee gravity. Our results are consistent with the previous literature. In particular, we find that the connection between Gaussian curvature and the radius of a circular orbit greatly simplifies the calculation.
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