The longitudinal dynamic flight stability of a bumblebee in forward flight is studied. The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eig...The longitudinal dynamic flight stability of a bumblebee in forward flight is studied. The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are employed for solving the equations of motion. The primary findings are as the following. The forward flight of the bumblebee is not dynamically stable due to the existence of one （or two） unstable or approximately neutrally stable natural modes of motion. At hovering to medium flight speed [flight speed Ue = （0-3.5）m s^-1; advance ratio J = 0-0.44], the flight is weakly unstable or approximately neutrally stable; at high speed （Ue = 4.5 m s^-1; J = 0.57）, the flight becomes strongly unstable （initial disturbance double its value in only 3.5 wingbeats）.展开更多
Geographic variation of flower size is potentially affected by various biotic and abiotic factors such as pollinator size, abundance of nectar robbers, and temperature. To elucidate the effect of geographic variation ...Geographic variation of flower size is potentially affected by various biotic and abiotic factors such as pollinator size, abundance of nectar robbers, and temperature. To elucidate the effect of geographic variation of flower-visitor fauna on flower size, we investigated two spring-flowering, bumblebee-pollinated herbs, Lamium album L. var. barbatum (seven populations) and Meehania urticifolia (five populations), in central Japan. Flower-size variations were not correlated with altitude (an index of abiotic environmental change) in either species, but in both species they were related to the local species composition of flower visitors. In L. album, flowers were bigger in populations visited by long-tongued Bombus consobrinus and B. diversus queens, whereas they were smaller in populations visited by short-tongued bees such as Apis mellifera. Flower size did not vary much among populations of M. urticifolia visited by long-tongued bumblebees, but it was uniquely small in a population whose flowers were predominantly visited by the nectar-robbing bee Megachile japonica. In conclusion, both the size and nectar-robbing behavior of bees affect local flower-size adaptation in these two long-tubed, spring-flowering herbs.展开更多
Floral traits modify pollinator behavior and shape the plant-pollinator interaction pattern at ecological and evolutionary levels. Biomechanical traits are important in mediating interactions between flowers and their...Floral traits modify pollinator behavior and shape the plant-pollinator interaction pattern at ecological and evolutionary levels. Biomechanical traits are important in mediating interactions between flowers and their pollinators in some cases, such as in buzz pollination. During buzz pollination, a bee produces vibrations using its thoracic muscles and transfers these vibrations primarily through its mandibles as it bites the flower. The interaction between buzz-pollinated flowers and their pollinators is influenced by their physical size relative to each other, but the drivers of these size-dependent associations remain unclear. Using eight beaked louseworts(Pedicularis) as a model system, we combined behavioral observations, biomechanical analyses, and pollinator network analyses to test the hypothesis that the location of where a bee bites should constrain the interaction between Pedicularis and bumblebees during buzz pollination. We found that bumblebees always chose to bite the same site at the base of the floral beak when buzzing Pedicularis, and this site is optimal for transferring vibrations from the bee to release pollen from the anthers. Bee bodies must be long enough for the mandibles to clamp onto the same optimal site on the floral beak, while its pollen-collecting abdomen is positioned at the opening of the floral beak where pollen grains are ejected. Our pollination networks showed size matching between the floral beak length of each Pedicularis species and the body length of individual bumblebees regardless of bee species. These results suggest that the optimal excitation point on the Pedicularis flower links a suite of floral traits to its pollinators' dimensions, potentially contributing to prezygotic isolation among co-flowering, sympatric Pedicularis species.展开更多
Bumblebees are important pollinators for many natural and agricultural systems in temperate regions.Interspecific and intraspecific variation in floral resource preferences have been proposed to influence bumblebee co...Bumblebees are important pollinators for many natural and agricultural systems in temperate regions.Interspecific and intraspecific variation in floral resource preferences have been proposed to influence bumblebee community structure.In particular,sexual dimorphism is a major source of intraspecific niche variation.Although interspecific resource partitioning is well studied,few studies have explored the intraspecific dynamics between workers and males.Here,we report a study on a total of 11528 workers and 2220 males of 14 bumblebee species recorded over 5 years in the Hengduan Mountains of Southwest China.We first compared the potential for interspecific and intraspecific competition between workers and males using visitation records and resource partitioning indices(overlap index).We then evaluated the influence of nectar traits on flower preference,including nectar volume and the levels of hexose,sucrose and 10 essential amino acids(EAAs).We found that the niche overlap between intraspecific workers and males was higher than that between different species,and temporal overlap alone did not strongly determine diet overlap.Males of most species preferred flowers with high levels of EAAs and hexose,whereas workers of some species preferred flowers with high nectar volume and sucrose levels.This study suggests that there is floral resource partitioning among bumblebee species,and between workers and males,which may play a key role in alleviating interspecific and intraspecific competition.These findings also provide a useful guide for which kinds of plants might be most valuable for bumblebees,especially the understudied males,in this biodiversity hotspot.展开更多
Bumblebees are a genus of pollinators(Bombus)that play important roles in natural ecosystem and agricultural production.Several bumblebee species have been recorded as under population decline,and the proportion of sp...Bumblebees are a genus of pollinators(Bombus)that play important roles in natural ecosystem and agricultural production.Several bumblebee species have been recorded as under population decline,and the proportion of species experiencing popula-tion decline within subgenus Thoracobombus is higher than average.Bombus opulentus is 1 species in Thoracobombus,but little is known about its recent population dynamics.Here,we employed conservation genomics methods to investigate the population dynam-ics of B.opulentus during the recent past and identify the likely environmental factors that may cause population decline.Firstly,we placed the scaffold-level of B.opulentus ref-erence genome sequence onto chromosome-level using Hi-C technique.Then,based on this reference genome and whole-genome resequencing data for 51 B.opulentus samples,we reconstructed the population structure and effective population size(Ne)trajectories of B.opulentus and identified genes that were under positive selection.Our results revealed that the collected B.opulentus samples could be divided into 2 populations,and 1 of them experienced a recent population decline;the declining population also exhibited lower ge-netic diversity and higher inbreeding levels.Genes related to high-temperature tolerance,immune response,and detoxication showed signals of positive selection in the declining population,suggesting that climate warming and pathogen/pesticide exposures may con-tribute to the decline of this B.opulentus population.Taken together,our study provided insights into the demography of B.opulentus populations and highlighted that popula-tions of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors.展开更多
Although the gut microbial communities in adult bumblebees and their as- sociated functionalities are widely studied, descriptive data on the larval gut microbiota are still limited. The gut microbiota of a fully samp...Although the gut microbial communities in adult bumblebees and their as- sociated functionalities are widely studied, descriptive data on the larval gut microbiota are still limited. The gut microbiota of a fully sampled wild Bombus pascuorum nest has been characterized, using the multiplexed Illumina MiSeq 16S ribosomal RNA ampli- con sequencing technique. The nesters and foragers inhabiting the same nest showed the typical core bacterial sequences and only marginal differences in their characterized gut microbiota. The gut microbial communities within the adult and larval specimens differed strongly, as the typical core gut bacteria in the adult bumblebees are absent in the larval bumblebees. The bacterial communities within the larval gut are dominated by bacterial phylotypes of Enterobacteriaceae and Lactobacillaceae, supplemented with genera be- longing to Corynebacteriales and Bacillales. The function of this larval gut microbiota, being different from the adult, remains to be determined.展开更多
Bumblebees play an important role in maintaining the balance of natural and agricultural ecosystems,and the characteristic gut microbiota of bumblebees exhibit significant mutualistic functions.China has the highest d...Bumblebees play an important role in maintaining the balance of natural and agricultural ecosystems,and the characteristic gut microbiota of bumblebees exhibit significant mutualistic functions.China has the highest diversity of bumblebees;however,gut microbiota of Chinese bumblebees have mostly been investigated through cultureindependent studies.Here,we analyzed the gut communities of bumblebees from Sichuan,Yunnan,and Shaanxi provinces in China through 16S ribosomal RNA amplicon sequencing and bacterial isolation.It revealed that the bumblebees examined in this study harbored two gut enterotypes as previously reported:one is dominated by Gilliamella and Snodgrassella,and the other is distinguished by prevalent environmental species.The gut compositions obviously varied among different individual bees.We then isolated 325 bacterial strains and the comparative genomic analysis of Gillianiella strains revealed that galactose and pectin digestion pathways were conserved in strains from bumblebees,while genes for the utilization of arabinose,mannose,xylose,and rhamnose were mostly lost.Only two strains from the Chinese bumblebees possess the multidrug-resistant gene emrB,which is phylogenetically closely related to that from the symbionts of soil entomopathogenic nematode.In contrast,tetracycline-resistant genes were uniquely present in three strains from the USA.Our results illustrate the prevalence of strain-level variations in the metabolic potentials and the distributions of antibiotic-resistant genes in Chinese bumblebee gut bacteria.展开更多
Social bees, like honeybees and bumblebees, have a close contact with nest mates of different developmental stages and generations. This could enhance bacterial transfer between nest mates and offers opportunities for...Social bees, like honeybees and bumblebees, have a close contact with nest mates of different developmental stages and generations. This could enhance bacterial transfer between nest mates and offers opportunities for direct transfer of symbionts from one generation to the next, resulting in a stable host specific gut microbiota. Gut sym- bionts of honeybees and bumblebees have been suggested to contribute in digestion and protection against parasites and pathogens. Here we studied the impact of contact with the bumblebee colony on the colonization potential of the bacterial families （i.e., Neisseri- aceae, Orbaceae, Lactobacillaceae and Bifidobacteriaceae） occurring in the gut of adult bumblebees （Bombus terrestris）. Bacterial profiles of the gut microbiota of B. terrestris were determined based on the hypervariable V4 region of the 16S rRNA using paired-end Illumina sequencing. In our experiments, we created different groups in which we grad- ually reduced the contact with nest mates and hive material. We made 3 observations： （i） reducing the contact between the colony and the bumblebee during adult life resulted in a significant drop in the relative abundance ofLactobacillus bombicola and Lactobacillus bombi; （ii） Bifidobacteriaceae required contact with nest mates to colonize the gut of B. terrestris and a significant lower bacterial diversity was observed in bumblebees that were completely excluded from colony contact during the adult life; （iii） Snodgrassella and Gilliamella were able to colonize the gut of the adult bumblebee without any direct contact with nest mates in the adult life stage. These results indicate the impact of the colony life on the diversity of the characteristic bumblebee gut bacteria.展开更多
Eusocial bumble and honey bees are important pollinators for global ecology and the agricultural economy.Although both the bumble and honey bees possess similar and host-restricted gut microbiota,they differ in aspect...Eusocial bumble and honey bees are important pollinators for global ecology and the agricultural economy.Although both the bumble and honey bees possess similar and host-restricted gut microbiota,they differ in aspects of morphology,autonomy,physiology,behavior,and life cycle.The social bee gut bacteria exhibit host specificity that is likely a result of long-term co-evolution.The unique life cycle of bumblebees is key for the acquisition and development of their gut microbiota,and affects the strain-level diversity of the core bacterial species.Studies on bumblebee gut bacteria show that they retain less functional capacity for carbohydrate metabolism compared with that of the honeybee.We discuss the potential roles of the bumblebee gut microbiota against pathogenic threats and the application of host-specific probiotics for bumblebees.Given the advantages of the bumblebee microbiome,including the simple structure and host specificity,and the ease of manipulating bumblebee colonies,we propose that bumblebees may provide a valuable system for understanding the general principles of host-microbe interactions,gut-brain axis,and vertical transmission.展开更多
Aims When sympatric flowering plant species in a natural community share pollinators,study of plant-plant interactions via interspecific pollen transfer(iPT)is essential for understanding species coexistence.However,l...Aims When sympatric flowering plant species in a natural community share pollinators,study of plant-plant interactions via interspecific pollen transfer(iPT)is essential for understanding species coexistence.However,little is known about the extent of iPT between interactive species and its causes.Methods To explore how sympatric flowering plants sharing pollinators mini-mize deleterious effects of iPT,we investigated the pollination ecol-ogy of two endemic species,Salvia przewalskii and Delphinium yuanum,in an alpine meadow in the Hengduan mountains,southwest China.We quantified conspecific and interspecific visits by shared bumblebee pollinators,amounts of pollen placed on different body sites of the pollinators and stigmatic pollen loads on open-pollinated flowers.To examine whether iPT affects female fitness,we measured pollen germination and seed production in the two species in an artificial pollination experiment.Important Findingsone bumblebee species,Bombus trifasciatus,was found to be the sole effective pollinator for the two coflowering species.Pollination experiments indicated that deposition of heterospecific pollen could significantly decrease seed set in both species.Experiments showed that S.przewalskii pollen could germinate well on stigmas of D.yuanum,inhibiting conspecific pollen germination in D.yuanum.However,seed set was not lower under open pollination than under cross-pollination within species,suggesting that no female fitness loss was caused by iPT.in foraging bouts with pollinator switches,switches from S.przewalskii to D.yuanum were relatively more fre-quent(8.27%)than the converse(1.72%).However,iPT from S.prze-walskii to D.yuanum accounted for only 1.82%of total stigmatic pollen loads while the reverse iPT to S.przewalskii was 8.70%,indi-cating that more switches of bumblebees to D.yuanum did not result in higher iPT.by contrast,selection for reduced iPT to S.przewalskii would limit pollinator switches from D.yuanum.We found that a bumblebee generally carried pollen grains from both species but the two species differed in the position of pollen placement on the bum-blebee’s body;S.przewalskii’s pollen was concentrated on the dorsal thorax while D.yuanum’s pollen was concentrated ventrally on the head.This differential pollen placement along with pollinator fidelity largely reduced iPT between the two species with a shared pollinator.展开更多
This study was conducted to evaluate the effects of four pesticides （Mosplian, Kingbo, Score and Lvrtong） applied commonly in greenhouses in China, on three bumblebee species （Bombus hypocrita, Bombus ignitus and B...This study was conducted to evaluate the effects of four pesticides （Mosplian, Kingbo, Score and Lvrtong） applied commonly in greenhouses in China, on three bumblebee species （Bombus hypocrita, Bombus ignitus and Bombuspatagiatus）. The study used a contact experiment and oral toxicity LD50 values. The results showed that the mortality for B. hypocrita after contacting the four pesticides was significantly lower than B. patagiatus and B. ignitus, but there was no significant difference between B. patagiatus and B. ignitus. The oral toxicity median lethal dose （LD50） value of Mosplian to B. hypocrita （0.0028/zg active ingredient/bee） was significantly higher than that to B. ignitus （0.0023μg active ingredient/bee） and B. patagiatus （0.0021μg active ingredient/bee）. Of the bee species, it can be concluded that B. hypocrita was the least susceptible to the four pesticides. The mortality rates of each bumblebee species after contact with Mosplian were significantly higher than for the other three pesticides and the control group. For Kingbo, the rates were significantly higher than the control group, but Score and Lvrtong exposed groups showed no significant increase in mortality relative to the control group. It can therefore be concluded that the pesticides differ in their negative influences on bumblebees, and that Mosplian is the most harmful.展开更多
The current bumblebee decline leads to inbreeding in populations that fosters a loss of allelic diversity and diploid male production. As diploid males are viable and their offspring are sterile, bumblebee populations...The current bumblebee decline leads to inbreeding in populations that fosters a loss of allelic diversity and diploid male production. As diploid males are viable and their offspring are sterile, bumblebee populations can quickly fall in a vortex of extinction. In this article, we investigate for the first time a potential premating mechanism through a major chemical reproductive trait （male cephalic labial gland secretions） that could prevent monandrous virgin queens from mating with diploid males. We focus our study on the cephalic labial gland secretions of diploid and haploid males ofBombus terrestris （L.）. Contrary to initial expectations, our results do not show any significant differentiation of cephalic labial gland secretions between diploid and haploid specimens. Queens seem therefore to be unable to avoid mating with diploid males based on their compositions of cephalic labial gland secretions. This suggests that the vortex of extinction of diploid males could not be stopped through premating avoidance based on the cephalic labial gland secretions but other mechanisms could avoid mating between diploid males and queens.展开更多
We obtain an exact slowly rotating Einstein-bumblebee black hole solution by solving the corresponding rr and tθ components of the gravitational field equations for both cases:A)b u=(0,b(r),0,0) and B) bu=(0,b(r),b(...We obtain an exact slowly rotating Einstein-bumblebee black hole solution by solving the corresponding rr and tθ components of the gravitational field equations for both cases:A)b u=(0,b(r),0,0) and B) bu=(0,b(r),b(θ),0) .Then,we check the other gravitational field equations and the bumblebee field motion equations using this solution.We find that for case A,there indeed exists a slowly rotating black hole solution for an arbitrary LV(Lorentz violation)coupling constant l;however,for case B,this slowly rotating solution exists if and only if coupling constant l is as small as or smaller than angular momentum a.Thus far,no full rotating black hole solution has been published;hence,the Newman-Janis algorithm cannot be used to generate a rotating solution in the Einstein-bumblebee theory.This is similar to the Einstein-aether theory,wherein only some slowly rotating black hole solutions exist.To study the effects of this broken Lorentz symmetry,we consider the black hole greybody factor and find that,for angular index l=0 ,LV constant l decreases the effective potential and enhances the absorption probability,which is similar to the results for the non-minimal derivative coupling theory.展开更多
Social parasitic Hymenopterans have evolved morphological, chemical, and behavioral adaptations to overcome the sophisticated recognition and defense systems of their social host to invade host nests and exploit their...Social parasitic Hymenopterans have evolved morphological, chemical, and behavioral adaptations to overcome the sophisticated recognition and defense systems of their social host to invade host nests and exploit their worker force. In bumblebees, so- cial parasitism appeared in at least 3 subgenera independently： in the subgenus Psithyrus consisting entirely of parasitic species, in the subgenus Alpinobombus with Bombus hy- perboreus, and in the subgenus Thoracobombus with B. inexspectatus. Cuckoo bumblebee males utilize species-specific cephalic labial gland secretions for mating purposes that can impact their inquiline strategy. We performed cephalic labial gland secretions in B. hyperboreus, B. inexspectatus and their hosts. Males of both parasitic species exhibited high species specific levels of cephalic gland secretions, including different main com- pounds. Our results showed no chemical mimicry in the cephalic gland secretions between inquilines and their host and we did not identify the repellent compounds already known in other cuckoo bumblebees.展开更多
In this study,we obtained an exact high dimensional anti-de Sitter(AdS)black hole solution in Einsteinbumblebee gravity theory.This AdS-like black hole can only exist with a linear functional potential of the bumblebe...In this study,we obtained an exact high dimensional anti-de Sitter(AdS)black hole solution in Einsteinbumblebee gravity theory.This AdS-like black hole can only exist with a linear functional potential of the bumblebee field.We found that the Smarr formula and the first law of black hole thermodynamics can still be constructed in this Lorentz symmetry breaking black hole spacetime,but the conceptions of the black hole horizon area/entropy and the volume inside the horizon should be renewed due to its anisotropy.We also found that two types of phase transition exist:small-large black hole phase transition and Hawking-Page phase transition,like those of the Schwarzschild AdS black hole.After Lorentz symmetry breaking,the black hole mass at the divergent point of heat capacity becomes small,and the Gibbs free energy of the meta-stable large black hole is also smaller,showing that the large stable black hole can be more easily formed.展开更多
基金the National Natural Science Foundation of China (10732030)
文摘The longitudinal dynamic flight stability of a bumblebee in forward flight is studied. The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are employed for solving the equations of motion. The primary findings are as the following. The forward flight of the bumblebee is not dynamically stable due to the existence of one （or two） unstable or approximately neutrally stable natural modes of motion. At hovering to medium flight speed [flight speed Ue = （0-3.5）m s^-1; advance ratio J = 0-0.44], the flight is weakly unstable or approximately neutrally stable; at high speed （Ue = 4.5 m s^-1; J = 0.57）, the flight becomes strongly unstable （initial disturbance double its value in only 3.5 wingbeats）.
文摘Geographic variation of flower size is potentially affected by various biotic and abiotic factors such as pollinator size, abundance of nectar robbers, and temperature. To elucidate the effect of geographic variation of flower-visitor fauna on flower size, we investigated two spring-flowering, bumblebee-pollinated herbs, Lamium album L. var. barbatum (seven populations) and Meehania urticifolia (five populations), in central Japan. Flower-size variations were not correlated with altitude (an index of abiotic environmental change) in either species, but in both species they were related to the local species composition of flower visitors. In L. album, flowers were bigger in populations visited by long-tongued Bombus consobrinus and B. diversus queens, whereas they were smaller in populations visited by short-tongued bees such as Apis mellifera. Flower size did not vary much among populations of M. urticifolia visited by long-tongued bumblebees, but it was uniquely small in a population whose flowers were predominantly visited by the nectar-robbing bee Megachile japonica. In conclusion, both the size and nectar-robbing behavior of bees affect local flower-size adaptation in these two long-tubed, spring-flowering herbs.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000)the Special Foundation for National Science and Technology Basic Research Program of China (2021FY100200)+2 种基金the National Natural Science Foundation of China (32071670)partially supported by a research grant from the Human Frontier Science Program (RGP0043/2022)partially supported by the National Science Foundation under awards No. CMMI-2221908 to MJ。
文摘Floral traits modify pollinator behavior and shape the plant-pollinator interaction pattern at ecological and evolutionary levels. Biomechanical traits are important in mediating interactions between flowers and their pollinators in some cases, such as in buzz pollination. During buzz pollination, a bee produces vibrations using its thoracic muscles and transfers these vibrations primarily through its mandibles as it bites the flower. The interaction between buzz-pollinated flowers and their pollinators is influenced by their physical size relative to each other, but the drivers of these size-dependent associations remain unclear. Using eight beaked louseworts(Pedicularis) as a model system, we combined behavioral observations, biomechanical analyses, and pollinator network analyses to test the hypothesis that the location of where a bee bites should constrain the interaction between Pedicularis and bumblebees during buzz pollination. We found that bumblebees always chose to bite the same site at the base of the floral beak when buzzing Pedicularis, and this site is optimal for transferring vibrations from the bee to release pollen from the anthers. Bee bodies must be long enough for the mandibles to clamp onto the same optimal site on the floral beak, while its pollen-collecting abdomen is positioned at the opening of the floral beak where pollen grains are ejected. Our pollination networks showed size matching between the floral beak length of each Pedicularis species and the body length of individual bumblebees regardless of bee species. These results suggest that the optimal excitation point on the Pedicularis flower links a suite of floral traits to its pollinators' dimensions, potentially contributing to prezygotic isolation among co-flowering, sympatric Pedicularis species.
基金supported by the National Natural Science Foundation of China(grants 31800194 and 32170241 to ZMY,grants 31970253 and 32270243 to CFY)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant XDB31010000 to QFW)+1 种基金supported by the Key Laboratory of the Zoological Systematics and Evolution of the Chinese Academy of Sciences(grant 2008DP173354)supported by the Chinese Academy of Science's President's International Fellowship Initiative(PIFI)(grant 2024PVC0046).
文摘Bumblebees are important pollinators for many natural and agricultural systems in temperate regions.Interspecific and intraspecific variation in floral resource preferences have been proposed to influence bumblebee community structure.In particular,sexual dimorphism is a major source of intraspecific niche variation.Although interspecific resource partitioning is well studied,few studies have explored the intraspecific dynamics between workers and males.Here,we report a study on a total of 11528 workers and 2220 males of 14 bumblebee species recorded over 5 years in the Hengduan Mountains of Southwest China.We first compared the potential for interspecific and intraspecific competition between workers and males using visitation records and resource partitioning indices(overlap index).We then evaluated the influence of nectar traits on flower preference,including nectar volume and the levels of hexose,sucrose and 10 essential amino acids(EAAs).We found that the niche overlap between intraspecific workers and males was higher than that between different species,and temporal overlap alone did not strongly determine diet overlap.Males of most species preferred flowers with high levels of EAAs and hexose,whereas workers of some species preferred flowers with high nectar volume and sucrose levels.This study suggests that there is floral resource partitioning among bumblebee species,and between workers and males,which may play a key role in alleviating interspecific and intraspecific competition.These findings also provide a useful guide for which kinds of plants might be most valuable for bumblebees,especially the understudied males,in this biodiversity hotspot.
基金This work was supported by the National Natural Science Foundation of China(Grant numbers 32270445 and 31971397)the Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 14th Fiveyear Plan(Grant number BPHR20220114)the Central Public-interest Scientific Institution Basal Research Fund(Grant numbers Y2019XK13 and Y2021XK16).
文摘Bumblebees are a genus of pollinators(Bombus)that play important roles in natural ecosystem and agricultural production.Several bumblebee species have been recorded as under population decline,and the proportion of species experiencing popula-tion decline within subgenus Thoracobombus is higher than average.Bombus opulentus is 1 species in Thoracobombus,but little is known about its recent population dynamics.Here,we employed conservation genomics methods to investigate the population dynam-ics of B.opulentus during the recent past and identify the likely environmental factors that may cause population decline.Firstly,we placed the scaffold-level of B.opulentus ref-erence genome sequence onto chromosome-level using Hi-C technique.Then,based on this reference genome and whole-genome resequencing data for 51 B.opulentus samples,we reconstructed the population structure and effective population size(Ne)trajectories of B.opulentus and identified genes that were under positive selection.Our results revealed that the collected B.opulentus samples could be divided into 2 populations,and 1 of them experienced a recent population decline;the declining population also exhibited lower ge-netic diversity and higher inbreeding levels.Genes related to high-temperature tolerance,immune response,and detoxication showed signals of positive selection in the declining population,suggesting that climate warming and pathogen/pesticide exposures may con-tribute to the decline of this B.opulentus population.Taken together,our study provided insights into the demography of B.opulentus populations and highlighted that popula-tions of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors.
文摘Although the gut microbial communities in adult bumblebees and their as- sociated functionalities are widely studied, descriptive data on the larval gut microbiota are still limited. The gut microbiota of a fully sampled wild Bombus pascuorum nest has been characterized, using the multiplexed Illumina MiSeq 16S ribosomal RNA ampli- con sequencing technique. The nesters and foragers inhabiting the same nest showed the typical core bacterial sequences and only marginal differences in their characterized gut microbiota. The gut microbial communities within the adult and larval specimens differed strongly, as the typical core gut bacteria in the adult bumblebees are absent in the larval bumblebees. The bacterial communities within the larval gut are dominated by bacterial phylotypes of Enterobacteriaceae and Lactobacillaceae, supplemented with genera be- longing to Corynebacteriales and Bacillales. The function of this larval gut microbiota, being different from the adult, remains to be determined.
基金This work was supported by the National Key R&D Program of China(Grant No.2019YFA0906500)National Natural Science Foundation of China Project 31870472 and 31470123.
文摘Bumblebees play an important role in maintaining the balance of natural and agricultural ecosystems,and the characteristic gut microbiota of bumblebees exhibit significant mutualistic functions.China has the highest diversity of bumblebees;however,gut microbiota of Chinese bumblebees have mostly been investigated through cultureindependent studies.Here,we analyzed the gut communities of bumblebees from Sichuan,Yunnan,and Shaanxi provinces in China through 16S ribosomal RNA amplicon sequencing and bacterial isolation.It revealed that the bumblebees examined in this study harbored two gut enterotypes as previously reported:one is dominated by Gilliamella and Snodgrassella,and the other is distinguished by prevalent environmental species.The gut compositions obviously varied among different individual bees.We then isolated 325 bacterial strains and the comparative genomic analysis of Gillianiella strains revealed that galactose and pectin digestion pathways were conserved in strains from bumblebees,while genes for the utilization of arabinose,mannose,xylose,and rhamnose were mostly lost.Only two strains from the Chinese bumblebees possess the multidrug-resistant gene emrB,which is phylogenetically closely related to that from the symbionts of soil entomopathogenic nematode.In contrast,tetracycline-resistant genes were uniquely present in three strains from the USA.Our results illustrate the prevalence of strain-level variations in the metabolic potentials and the distributions of antibiotic-resistant genes in Chinese bumblebee gut bacteria.
文摘Social bees, like honeybees and bumblebees, have a close contact with nest mates of different developmental stages and generations. This could enhance bacterial transfer between nest mates and offers opportunities for direct transfer of symbionts from one generation to the next, resulting in a stable host specific gut microbiota. Gut sym- bionts of honeybees and bumblebees have been suggested to contribute in digestion and protection against parasites and pathogens. Here we studied the impact of contact with the bumblebee colony on the colonization potential of the bacterial families （i.e., Neisseri- aceae, Orbaceae, Lactobacillaceae and Bifidobacteriaceae） occurring in the gut of adult bumblebees （Bombus terrestris）. Bacterial profiles of the gut microbiota of B. terrestris were determined based on the hypervariable V4 region of the 16S rRNA using paired-end Illumina sequencing. In our experiments, we created different groups in which we grad- ually reduced the contact with nest mates and hive material. We made 3 observations： （i） reducing the contact between the colony and the bumblebee during adult life resulted in a significant drop in the relative abundance ofLactobacillus bombicola and Lactobacillus bombi; （ii） Bifidobacteriaceae required contact with nest mates to colonize the gut of B. terrestris and a significant lower bacterial diversity was observed in bumblebees that were completely excluded from colony contact during the adult life; （iii） Snodgrassella and Gilliamella were able to colonize the gut of the adult bumblebee without any direct contact with nest mates in the adult life stage. These results indicate the impact of the colony life on the diversity of the characteristic bumblebee gut bacteria.
基金This work was supported by the National Key R&D Pro-gram of China(Grant No.2019YFA0906500)National Natural Science Foundation of China Project 32170495.
文摘Eusocial bumble and honey bees are important pollinators for global ecology and the agricultural economy.Although both the bumble and honey bees possess similar and host-restricted gut microbiota,they differ in aspects of morphology,autonomy,physiology,behavior,and life cycle.The social bee gut bacteria exhibit host specificity that is likely a result of long-term co-evolution.The unique life cycle of bumblebees is key for the acquisition and development of their gut microbiota,and affects the strain-level diversity of the core bacterial species.Studies on bumblebee gut bacteria show that they retain less functional capacity for carbohydrate metabolism compared with that of the honeybee.We discuss the potential roles of the bumblebee gut microbiota against pathogenic threats and the application of host-specific probiotics for bumblebees.Given the advantages of the bumblebee microbiome,including the simple structure and host specificity,and the ease of manipulating bumblebee colonies,we propose that bumblebees may provide a valuable system for understanding the general principles of host-microbe interactions,gut-brain axis,and vertical transmission.
基金National Science Foundation of China(31030016,31270281)to SQ Huang.
文摘Aims When sympatric flowering plant species in a natural community share pollinators,study of plant-plant interactions via interspecific pollen transfer(iPT)is essential for understanding species coexistence.However,little is known about the extent of iPT between interactive species and its causes.Methods To explore how sympatric flowering plants sharing pollinators mini-mize deleterious effects of iPT,we investigated the pollination ecol-ogy of two endemic species,Salvia przewalskii and Delphinium yuanum,in an alpine meadow in the Hengduan mountains,southwest China.We quantified conspecific and interspecific visits by shared bumblebee pollinators,amounts of pollen placed on different body sites of the pollinators and stigmatic pollen loads on open-pollinated flowers.To examine whether iPT affects female fitness,we measured pollen germination and seed production in the two species in an artificial pollination experiment.Important Findingsone bumblebee species,Bombus trifasciatus,was found to be the sole effective pollinator for the two coflowering species.Pollination experiments indicated that deposition of heterospecific pollen could significantly decrease seed set in both species.Experiments showed that S.przewalskii pollen could germinate well on stigmas of D.yuanum,inhibiting conspecific pollen germination in D.yuanum.However,seed set was not lower under open pollination than under cross-pollination within species,suggesting that no female fitness loss was caused by iPT.in foraging bouts with pollinator switches,switches from S.przewalskii to D.yuanum were relatively more fre-quent(8.27%)than the converse(1.72%).However,iPT from S.prze-walskii to D.yuanum accounted for only 1.82%of total stigmatic pollen loads while the reverse iPT to S.przewalskii was 8.70%,indi-cating that more switches of bumblebees to D.yuanum did not result in higher iPT.by contrast,selection for reduced iPT to S.przewalskii would limit pollinator switches from D.yuanum.We found that a bumblebee generally carried pollen grains from both species but the two species differed in the position of pollen placement on the bum-blebee’s body;S.przewalskii’s pollen was concentrated on the dorsal thorax while D.yuanum’s pollen was concentrated ventrally on the head.This differential pollen placement along with pollinator fidelity largely reduced iPT between the two species with a shared pollinator.
基金We would like to thank Dr. Regula Schmid-Hempel and Dr. Ben Sadd for their help in revising this paper, and Zhan-Bao Guo, Yue-Ming Tong, Hai-Yan Shi and Wen- Feng Chen for help and advice in the lab. This work was financially supported by grants from Chinese National Natural Science Foundation for Young Scholars （NO. 30700606）, the R＆D Special Fund for Public Welfare Industry （agriculture） （nyhyzx07-041） and China Application of Advances in Agricultural Science and Technology Projects （NO. 2006GB23260392）.
文摘This study was conducted to evaluate the effects of four pesticides （Mosplian, Kingbo, Score and Lvrtong） applied commonly in greenhouses in China, on three bumblebee species （Bombus hypocrita, Bombus ignitus and Bombuspatagiatus）. The study used a contact experiment and oral toxicity LD50 values. The results showed that the mortality for B. hypocrita after contacting the four pesticides was significantly lower than B. patagiatus and B. ignitus, but there was no significant difference between B. patagiatus and B. ignitus. The oral toxicity median lethal dose （LD50） value of Mosplian to B. hypocrita （0.0028/zg active ingredient/bee） was significantly higher than that to B. ignitus （0.0023μg active ingredient/bee） and B. patagiatus （0.0021μg active ingredient/bee）. Of the bee species, it can be concluded that B. hypocrita was the least susceptible to the four pesticides. The mortality rates of each bumblebee species after contact with Mosplian were significantly higher than for the other three pesticides and the control group. For Kingbo, the rates were significantly higher than the control group, but Score and Lvrtong exposed groups showed no significant increase in mortality relative to the control group. It can therefore be concluded that the pesticides differ in their negative influences on bumblebees, and that Mosplian is the most harmful.
文摘The current bumblebee decline leads to inbreeding in populations that fosters a loss of allelic diversity and diploid male production. As diploid males are viable and their offspring are sterile, bumblebee populations can quickly fall in a vortex of extinction. In this article, we investigate for the first time a potential premating mechanism through a major chemical reproductive trait （male cephalic labial gland secretions） that could prevent monandrous virgin queens from mating with diploid males. We focus our study on the cephalic labial gland secretions of diploid and haploid males ofBombus terrestris （L.）. Contrary to initial expectations, our results do not show any significant differentiation of cephalic labial gland secretions between diploid and haploid specimens. Queens seem therefore to be unable to avoid mating with diploid males based on their compositions of cephalic labial gland secretions. This suggests that the vortex of extinction of diploid males could not be stopped through premating avoidance based on the cephalic labial gland secretions but other mechanisms could avoid mating between diploid males and queens.
基金Supported by the Scientific Research Fund of the Hunan Provincial Education Department(19A257)the National Natural Science Foundation(NNSFC)of China(11247013)Hunan Provincial Natural Science Foundation of China(2015JJ2085)。
文摘We obtain an exact slowly rotating Einstein-bumblebee black hole solution by solving the corresponding rr and tθ components of the gravitational field equations for both cases:A)b u=(0,b(r),0,0) and B) bu=(0,b(r),b(θ),0) .Then,we check the other gravitational field equations and the bumblebee field motion equations using this solution.We find that for case A,there indeed exists a slowly rotating black hole solution for an arbitrary LV(Lorentz violation)coupling constant l;however,for case B,this slowly rotating solution exists if and only if coupling constant l is as small as or smaller than angular momentum a.Thus far,no full rotating black hole solution has been published;hence,the Newman-Janis algorithm cannot be used to generate a rotating solution in the Einstein-bumblebee theory.This is similar to the Einstein-aether theory,wherein only some slowly rotating black hole solutions exist.To study the effects of this broken Lorentz symmetry,we consider the black hole greybody factor and find that,for angular index l=0 ,LV constant l decreases the effective potential and enhances the absorption probability,which is similar to the results for the non-minimal derivative coupling theory.
文摘Social parasitic Hymenopterans have evolved morphological, chemical, and behavioral adaptations to overcome the sophisticated recognition and defense systems of their social host to invade host nests and exploit their worker force. In bumblebees, so- cial parasitism appeared in at least 3 subgenera independently： in the subgenus Psithyrus consisting entirely of parasitic species, in the subgenus Alpinobombus with Bombus hy- perboreus, and in the subgenus Thoracobombus with B. inexspectatus. Cuckoo bumblebee males utilize species-specific cephalic labial gland secretions for mating purposes that can impact their inquiline strategy. We performed cephalic labial gland secretions in B. hyperboreus, B. inexspectatus and their hosts. Males of both parasitic species exhibited high species specific levels of cephalic gland secretions, including different main com- pounds. Our results showed no chemical mimicry in the cephalic gland secretions between inquilines and their host and we did not identify the repellent compounds already known in other cuckoo bumblebees.
基金Supported by the Scientific Research Fund of the Hunan Provincial Education Department(19A257 and 19A260)the National Natural Science Foundation(NNSFC)of China(11247013)Hunan Provincial Natural Science Foundation of China(2015JJ2085)。
文摘In this study,we obtained an exact high dimensional anti-de Sitter(AdS)black hole solution in Einsteinbumblebee gravity theory.This AdS-like black hole can only exist with a linear functional potential of the bumblebee field.We found that the Smarr formula and the first law of black hole thermodynamics can still be constructed in this Lorentz symmetry breaking black hole spacetime,but the conceptions of the black hole horizon area/entropy and the volume inside the horizon should be renewed due to its anisotropy.We also found that two types of phase transition exist:small-large black hole phase transition and Hawking-Page phase transition,like those of the Schwarzschild AdS black hole.After Lorentz symmetry breaking,the black hole mass at the divergent point of heat capacity becomes small,and the Gibbs free energy of the meta-stable large black hole is also smaller,showing that the large stable black hole can be more easily formed.
