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
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
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
Biomimetics (or bionics) is the engineering discipline that constructs artificial systems using biological principles. The ideal final result in biomimetics is to create a living machine. But what are the desirable an...Biomimetics (or bionics) is the engineering discipline that constructs artificial systems using biological principles. The ideal final result in biomimetics is to create a living machine. But what are the desirable and non-desirable properties of biomimetic product? Where can natural prototypes be found? How can technical solutions be transferred from nature to technology? Can we use living nature like LEGO bricks for construction our machines? How can biology help us? What is a living machine? In biomimetic practice only some “part” (organ, part of organ, tissue) of the observed whole organism is utilized. A possible template for future super-organism extension for biomimetic methods might be drawn from experiments in holistic ecological agriculture (ecological design, permaculture, ecological engineering, etc.). The necessary translation of these rules to practical action can be achieved with the Russian Theory of Inventive Problem Solving (TRIZ), specifically adjusted to biology. Thus, permaculture, reinforced by a TRIZ conceptual framework, might provide the basis for Super-Organismic Bionics, which is hypothesized as necessary for effective ecological engineering. This hypothesis is supported by a case study-the design of a sustainable artificial nature reserve for wild pollinators as a living machine.展开更多
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
Floral size is potentially influenced by local pollinators’ body size. As pollinator fauna and size often change with elevation, correlation between elevational variation of pollinator size and floral size is expecte...Floral size is potentially influenced by local pollinators’ body size. As pollinator fauna and size often change with elevation, correlation between elevational variation of pollinator size and floral size is expected. We investigated the variation of floral size in Prunella vulgaris L. (Laminaceae) and the variation of their pollinator fauna along an elevational gradient. We measured the floral size of four traits: corolla length (CL), corolla tube length (CTL), corolla width (CW), and calyx length (CAL), in 23 populations, and found that CL and CTL were negatively correlated with elevation, and CW and CAL were not. Six bumblebee species visited the flower, and the visiting bee fauna differed among populations;the smallest and the largest bumblebee species visited the high elevational range (above 1800 m a. s. l.) populations, and the largest and the second largest bumblebee species visited the middle elevational range (1400 - 1800 m a. s. l.). Although abiotic factors can potentially affect floral size, the fact that we do not find an elevational decrease in CW and CAL suggests that the elevational change in P. vulgaris’s CL and CTL reflects the local pollinator size.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
Many studies have argued the importance of the flower-pollinator size matching for flower trait diversification. However, non-pollinator agents may also influence flower traits. In this study, we investigated the alti...Many studies have argued the importance of the flower-pollinator size matching for flower trait diversification. However, non-pollinator agents may also influence flower traits. In this study, we investigated the altitudinal variation of flower size (spur length, stamen length, petal blade length, corolla diameter, and sepal length) and flower visitors of Aquilegia buergeriana var. buergeriana (long-spurred columbine) in central Japan. Although this species was primarily visited by Bombus consobrinus, which has an unvarying mouthpart length, flower sizes varied greatly among populations with no correlation with altitude. These results suggest that non-pollinator and non-meteorological agents, directly and/or indirectly, impose selection pressure on flower size in A. buergeriana.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
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
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.
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.
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.
文摘Biomimetics (or bionics) is the engineering discipline that constructs artificial systems using biological principles. The ideal final result in biomimetics is to create a living machine. But what are the desirable and non-desirable properties of biomimetic product? Where can natural prototypes be found? How can technical solutions be transferred from nature to technology? Can we use living nature like LEGO bricks for construction our machines? How can biology help us? What is a living machine? In biomimetic practice only some “part” (organ, part of organ, tissue) of the observed whole organism is utilized. A possible template for future super-organism extension for biomimetic methods might be drawn from experiments in holistic ecological agriculture (ecological design, permaculture, ecological engineering, etc.). The necessary translation of these rules to practical action can be achieved with the Russian Theory of Inventive Problem Solving (TRIZ), specifically adjusted to biology. Thus, permaculture, reinforced by a TRIZ conceptual framework, might provide the basis for Super-Organismic Bionics, which is hypothesized as necessary for effective ecological engineering. This hypothesis is supported by a case study-the design of a sustainable artificial nature reserve for wild pollinators as a living machine.
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Floral size is potentially influenced by local pollinators’ body size. As pollinator fauna and size often change with elevation, correlation between elevational variation of pollinator size and floral size is expected. We investigated the variation of floral size in Prunella vulgaris L. (Laminaceae) and the variation of their pollinator fauna along an elevational gradient. We measured the floral size of four traits: corolla length (CL), corolla tube length (CTL), corolla width (CW), and calyx length (CAL), in 23 populations, and found that CL and CTL were negatively correlated with elevation, and CW and CAL were not. Six bumblebee species visited the flower, and the visiting bee fauna differed among populations;the smallest and the largest bumblebee species visited the high elevational range (above 1800 m a. s. l.) populations, and the largest and the second largest bumblebee species visited the middle elevational range (1400 - 1800 m a. s. l.). Although abiotic factors can potentially affect floral size, the fact that we do not find an elevational decrease in CW and CAL suggests that the elevational change in P. vulgaris’s CL and CTL reflects the local pollinator size.
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.
文摘Many studies have argued the importance of the flower-pollinator size matching for flower trait diversification. However, non-pollinator agents may also influence flower traits. In this study, we investigated the altitudinal variation of flower size (spur length, stamen length, petal blade length, corolla diameter, and sepal length) and flower visitors of Aquilegia buergeriana var. buergeriana (long-spurred columbine) in central Japan. Although this species was primarily visited by Bombus consobrinus, which has an unvarying mouthpart length, flower sizes varied greatly among populations with no correlation with altitude. These results suggest that non-pollinator and non-meteorological agents, directly and/or indirectly, impose selection pressure on flower size in A. buergeriana.
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.
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.
