Plant-pollinator interactions can be highly variable across years in natural communities.Although variation in the species composition and its basic structure has been investigated to understand the dynamic nature of ...Plant-pollinator interactions can be highly variable across years in natural communities.Although variation in the species composition and its basic structure has been investigated to understand the dynamic nature of pollination networks,little is known about the temporal dynamic of interaction strength between the same plant and pollinator species in any natural community.Pollinator-mediated selection on the evolution of floral traits could be diminished if plant-pollinator interactions vary temporally.To quantify the temporal variation in plant-pollinator interactions and the interaction strength(observed visits),we compared weighted networks between plants and pollinators in a biodiverse alpine meadow in Shangri-La,southwest China for 3 consecutive years.Although plant-pollinator interactions were highly dynamic such that identical interactions only accounted for 10.7%of the total between pair years,the diversity of interactions was stable.These identical interactions contributed 41.2%of total visits and were similar in strength and weighted nestedness.For plant species,72.6%of species were visited by identical pollinator species between pair years,accounting for over half of the total visits and three-quarters at the functional group level.More generalized pollinators contributed more connectiveness and were more central in networks across years.However,there was no similar or even opposite trend for plant species,which suggested that specialized plant species may also be central in pollinator networks.The variation in pollinator composition decreased as pollinator species numbers increased,suggesting that generalized plants experienced stable pollinator partition.The stable,tight interactions between generalized pollinators and specialized plants represent cornerstones of the studied community.展开更多
This research was carried out to evaluate the foraging behaviour of Apis mellifera and Scaptotrigona bipunctata and its relationship with environmental variables in Dombeya wallichii considering the following aspects:...This research was carried out to evaluate the foraging behaviour of Apis mellifera and Scaptotrigona bipunctata and its relationship with environmental variables in Dombeya wallichii considering the following aspects: 1) Type of resource harvested, 2) Visitation rate, 3) Length of visit, 4) sugar concentration in the stored nectar in the honey crop of A. mellifera and secreted by the flower and 5) floral constancy. Both species collected mainly nectar, with a visitation rate of 4.2 flowers for A. mellifera and 1.1 flowers for S. bipunctata and visit length of 9.2 and 34.2 seconds, respectively. The sugar concentration had a positive relationship with temperature and luminosity, with mean values of 12.3% in the nectar and 14.2% in the honey crop. Bees were classified by specialists because the pollen of D. wallichii was predominant in the pollen basket, but the pollen of Emilia sonchifolia and Raphanus sativus was also found. These results suggest that the species under study take advantage of the resources offered by D. wallichii, therefore, this species is an important source for the maintenance of the bees in the season of lack of food.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
Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interac- tions between them has led to a recent surge in research. Much of this research has addressed the co...Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interac- tions between them has led to a recent surge in research. Much of this research has addressed the consequences of warming for phenological and distributional shifts. In contrast, relatively little is known about the physiological responses of plants and insect pollinators to climate warming and, in particular, how these responses might affect plant-pollinator interactions. Here, we summa- rize the direct physiological effects of temperature on flowering plants and pollinating insects to highlight ways in which plant and pollinator responses could affect floral resources for pollinators, and pollination success for plants, respectively. We also con- sider the overall effects of these responses on plant-pollinator interaction networks. Plant responses to wanning, which include altered flower, nectar, and pollen production, could modify floral resource availability and reproductive output of pollinating in- sects. Similarly, pollinator responses, such as altered foraging activity, body size, and life span, could affect patterns of pollen flow and pollination success of flowering plants. As a result, network structure could be altered as interactions are gained and lost, weakened and strengthened, even without the gain or loss of species or temporal overlap. Future research that addresses not only how plant and pollinator physiology are affected by warming but also how responses scale up to affect interactions and networks should allow us to better understand and predict the effects of climate change on this important ecosystem service .展开更多
There is increasing interest in flies as potentially important pollinators. Flies are known to have a complex visual system, in eluding 4 spectral classes of photoreceptors that con tribute to the perception of color....There is increasing interest in flies as potentially important pollinators. Flies are known to have a complex visual system, in eluding 4 spectral classes of photoreceptors that con tribute to the perception of color. Our current understanding of how color signals are perceived by flies is based on data for the blowfly Lucilia sp., which after being conditi oned to rewarded mono chromatic light stimuli, showed evidenee of a categorical color visual system. The resulting opponent fly color space has 4 distinct categories, and has been used to interpret how some fly pollinators may perceive flower colors. However, formal proof that flower flies (Syrphidae) only use a simple, categorical color process remains outstanding. In free-flying experiments, we tested the hoverfly Eristalis tenax, a Batesian mimic of the honeybee, that receives its nutrition by visiting flowers. Using a range of broadband similar-dissimilar color stimuli previously used to test color perception in pollinating hymenopteran species, we evaluated if there are steep changes in behavioral choices with continuously increasing color differences as might be expected by categorical color processing. Our data revealed that color choices by the hoverfly are mediated by a continuous monotonic function. Thus, these flies did not use a categorical processing, but showed evidenee of a color discrimination function similar to that observed in several bee species. We therefore empirically provide data for the minimum color distanee that can be discriminated by hoverflies in fly color space, enabling an improved un derstandi ng of plant-poll in ator interactions with a non-model insect species.展开更多
基金supported by the National Science Foundation of China(Nos.31300451 and 31030016).
文摘Plant-pollinator interactions can be highly variable across years in natural communities.Although variation in the species composition and its basic structure has been investigated to understand the dynamic nature of pollination networks,little is known about the temporal dynamic of interaction strength between the same plant and pollinator species in any natural community.Pollinator-mediated selection on the evolution of floral traits could be diminished if plant-pollinator interactions vary temporally.To quantify the temporal variation in plant-pollinator interactions and the interaction strength(observed visits),we compared weighted networks between plants and pollinators in a biodiverse alpine meadow in Shangri-La,southwest China for 3 consecutive years.Although plant-pollinator interactions were highly dynamic such that identical interactions only accounted for 10.7%of the total between pair years,the diversity of interactions was stable.These identical interactions contributed 41.2%of total visits and were similar in strength and weighted nestedness.For plant species,72.6%of species were visited by identical pollinator species between pair years,accounting for over half of the total visits and three-quarters at the functional group level.More generalized pollinators contributed more connectiveness and were more central in networks across years.However,there was no similar or even opposite trend for plant species,which suggested that specialized plant species may also be central in pollinator networks.The variation in pollinator composition decreased as pollinator species numbers increased,suggesting that generalized plants experienced stable pollinator partition.The stable,tight interactions between generalized pollinators and specialized plants represent cornerstones of the studied community.
文摘This research was carried out to evaluate the foraging behaviour of Apis mellifera and Scaptotrigona bipunctata and its relationship with environmental variables in Dombeya wallichii considering the following aspects: 1) Type of resource harvested, 2) Visitation rate, 3) Length of visit, 4) sugar concentration in the stored nectar in the honey crop of A. mellifera and secreted by the flower and 5) floral constancy. Both species collected mainly nectar, with a visitation rate of 4.2 flowers for A. mellifera and 1.1 flowers for S. bipunctata and visit length of 9.2 and 34.2 seconds, respectively. The sugar concentration had a positive relationship with temperature and luminosity, with mean values of 12.3% in the nectar and 14.2% in the honey crop. Bees were classified by specialists because the pollen of D. wallichii was predominant in the pollen basket, but the pollen of Emilia sonchifolia and Raphanus sativus was also found. These results suggest that the species under study take advantage of the resources offered by D. wallichii, therefore, this species is an important source for the maintenance of the bees in the season of lack of food.
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.
文摘Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interac- tions between them has led to a recent surge in research. Much of this research has addressed the consequences of warming for phenological and distributional shifts. In contrast, relatively little is known about the physiological responses of plants and insect pollinators to climate warming and, in particular, how these responses might affect plant-pollinator interactions. Here, we summa- rize the direct physiological effects of temperature on flowering plants and pollinating insects to highlight ways in which plant and pollinator responses could affect floral resources for pollinators, and pollination success for plants, respectively. We also con- sider the overall effects of these responses on plant-pollinator interaction networks. Plant responses to wanning, which include altered flower, nectar, and pollen production, could modify floral resource availability and reproductive output of pollinating in- sects. Similarly, pollinator responses, such as altered foraging activity, body size, and life span, could affect patterns of pollen flow and pollination success of flowering plants. As a result, network structure could be altered as interactions are gained and lost, weakened and strengthened, even without the gain or loss of species or temporal overlap. Future research that addresses not only how plant and pollinator physiology are affected by warming but also how responses scale up to affect interactions and networks should allow us to better understand and predict the effects of climate change on this important ecosystem service .
文摘There is increasing interest in flies as potentially important pollinators. Flies are known to have a complex visual system, in eluding 4 spectral classes of photoreceptors that con tribute to the perception of color. Our current understanding of how color signals are perceived by flies is based on data for the blowfly Lucilia sp., which after being conditi oned to rewarded mono chromatic light stimuli, showed evidenee of a categorical color visual system. The resulting opponent fly color space has 4 distinct categories, and has been used to interpret how some fly pollinators may perceive flower colors. However, formal proof that flower flies (Syrphidae) only use a simple, categorical color process remains outstanding. In free-flying experiments, we tested the hoverfly Eristalis tenax, a Batesian mimic of the honeybee, that receives its nutrition by visiting flowers. Using a range of broadband similar-dissimilar color stimuli previously used to test color perception in pollinating hymenopteran species, we evaluated if there are steep changes in behavioral choices with continuously increasing color differences as might be expected by categorical color processing. Our data revealed that color choices by the hoverfly are mediated by a continuous monotonic function. Thus, these flies did not use a categorical processing, but showed evidenee of a color discrimination function similar to that observed in several bee species. We therefore empirically provide data for the minimum color distanee that can be discriminated by hoverflies in fly color space, enabling an improved un derstandi ng of plant-poll in ator interactions with a non-model insect species.
