1 Multiple-species floral displays have been hypothesized to facilitate pollination by attracting a greater number and/or diversity of pollinators. Here I present experimental confirmation of ...pollination facilitation among coflowering plants that have morphologically distinct flowers. 2 Pollinator visits to Raphanus raphanistrum, a self-incompatible herbaceous plant, increased when it occurred with one or a combination of Cirsium arvense, Hypericum perforatum and Solidago canadensis than when it occurred alone. 3 Enhanced visitation to R. raphanistrum in mixed species plots was reflected by increased seed production. 4 Facilitative effects in pollination were conditional on the density and evenness of the floral mixture and graded into competition as the relative abundance of R. raphanistrum declined in a two-species mixture. 5 Previously proposed mechanisms for facilitative interactions cannot explain facilitation among florally distinct plant displays. An alternative mechanism of differential but complementary floral rewards is proposed to explain facilitative attraction of pollinators. 6 Facilitation of, and competition for, pollination has implications for regeneration by seed of rare or isolated plants, and of mitigating Allee effects that afflict such populations.
Enhancing the diversity of mass‐flowering crops (i.e. crop diversity) in agricultural landscapes is often proposed as a measure to favour pollinators and pollination, but it is uncertain whether crop ...diversity enhances pollinator richness on the wide landscape level.
Here, we surveyed pollinator communities in semi‐natural habitats and mass‐flowering crops throughout the whole growing season in 26 agricultural landscapes to examine how the temporal and spatial heterogeneity in semi‐natural habitats and crop diversity support pollinator species richness.
Crop diversity was unrelated to pollinator richness in the wider landscape, and temporal and spatial heterogeneity in semi‐natural habitats were equally important in determining pollinator richness. Surprisingly, the crop pollinator species pool size was a fixed proportion of the landscape pollinator species pool along a 0%–72% semi‐natural habitat cover gradient.
Synthesis and applications. Our results suggest that increasing crop diversity alone does not contribute to maintaining diverse wild pollinator communities in agricultural landscapes and emphasize the key role of temporally stable habitats such as semi‐natural habitats to maintain rich pollinator communities.
Resumen
Aumentar la diversidad de cultivos que florecen de manera masiva, se propone a menudo como una medida que podría favorecer a los polinizadores y la polinización en paisajes agrícolas. Sin embargo, es incierto si la diversidad de cultivos puede incrementar la riqueza de especies de polinizadores a escala de paisaje.
Aquí, muestreamos las comunidades de polinizadores en hábitats seminaturales y en cultivos de floración masiva en 26 paisajes agrícolas durante toda la estación. Examinamos en qué medida la heterogeneidad temporal y espacial en hábitats seminaturales, así como la diversidad de cultivos mantienen la riqueza de especies de polinizadores.
Los resultados mostraron que la diversidad de cultivos no se relacionó con la riqueza de polinizadores a escala de paisaje. Además, tanto la heterogeneidad temporal como la heterogeneidad espacial en hábitats seminaturales determinaron de forma similar la riqueza de polinizadores. Sorprendentemente, la proporción de especies de polinizadores que utilizaron los cultivos con respecto al total de especies en todo el paisaje fue constante a lo largo de un gradiente de 0%–72% de hábitat seminatural.
Síntesis y aplicaciones. Nuestros resultados sugieren que sólo incrementar la diversidad de cultivos no contribuye a mantener comunidades de polinizadores diversas en paisajes agrícolas. Además, enfatizan la importancia de mantener hábitats temporalmente estables, como los hábitats seminaturales para mantener comunidades de polinizadores diversas.
Our results suggest that increasing crop diversity alone does not contribute to maintaining diverse wild pollinator communities in agricultural landscapes and emphasize the key role of temporally stable habitats such as semi‐natural habitats to maintain rich pollinator communities.
Most flowering plants rely on pollinators for their reproduction. Plant‐pollinator interactions, although mutualistic, involve an inherent conflict of interest between both partners and may constrain ...plant mating systems at multiple levels: the immediate ecological plant selfing rates, their distribution in and contribution to pollination networks, and their evolution. Here, we review experimental evidence that pollinator behaviour influences plant selfing rates in pairs of interacting species, and that plants can modify pollinator behaviour through plastic and evolutionary changes in floral traits. We also examine how theoretical studies include pollinators, implicitly or explicitly, to investigate the role of their foraging behaviour in plant mating system evolution. In doing so, we call for more evolutionary models combining ecological and genetic factors, and additional experimental data, particularly to describe pollinator foraging behaviour. Finally, we show that recent developments in ecological network theory help clarify the impact of community‐level interactions on plant selfing rates and their evolution and suggest new research avenues to expand the study of mating systems of animal‐pollinated plant species to the level of the plant‐pollinator networks.
PREMISE OF THE STUDY:
The ability to attract pollinators is crucial to plants that rely on insects for pollination. We contrasted the roles of floral display size and flower color in attracting three ...bee species and determined the relationships between plant attractiveness (number of pollinator visits) and seed set for each bee species.
METHODS:
We recorded pollinator visits to plants, measured plant traits, and quantified plant reproductive success. A zero‐inflated Poisson regression model indicated plant traits associated with pollinator attraction. It identified traits that increased the number of bee visits and traits that increased the probability of a plant not receiving any visits. Different components of floral display size were examined and two models of flower color contrasted. Relationships between plant attractiveness and seed set were determined using regression analyses.
KEY RESULTS:
Plants with more racemes received more bee visits from all three bee species. Plants with few racemes were more likely not to receive any bee visits. The role of flower color varied with bee species and was influenced by the choice of the flower color model. Increasing bee visits increased seed set for all three bee species, with the steepest slope for leafcutting bees, followed by bumble bees, and finally honey bees.
CONCLUSIONS:
Floral display size influenced pollinator attraction more consistently than flower color. The same plant traits affected the probability of not being visited and the number of pollinator visits received. The impact of plant attractiveness on female reproductive success varied, together with pollinator effectiveness, by pollinator species.
The introduction of an alien plant is widely assumed to have negative consequences for the pollinator‐mediated fitness of nearby natives. Indeed, a number of studies, including a highly cited ...meta‐analysis, have concluded that the trend for such interactions is competitive. Here we provide evidence that publication bias and study design have obscured our ability to assess the pollinator‐mediated impacts of alien plants. In a meta‐analysis of 76 studies, we demonstrate that alien/native status does not predict the outcome of pollinator‐mediated interactions among plants. Moreover, we found no evidence that similarity in floral traits or phylogenetic distance between species pairs influences the outcome of pollinator‐mediated interactions. Instead, we report that aspects of study design, such as distance between the control and nearest neighbour, and/or the arrangement of study plants better predict the impact of a neighbour than does alien/native status. Our study sheds new light on the role that publication bias and experimental design play in the evaluation of key patterns in ecology. We conclude that, due to the absence of clear, generalisable pollinator‐mediated impacts of alien species, management schemes should base decisions on community‐wide assessments of the impacts of individual alien plant species, and not solely on alien/native status itself.
•A new Bee Pollinator Flower Pollination Algorithm (BPFPA) is proposed for Solar PV Parameter extraction.•Standard RTC France data is used for the experimentation of BPFPA algorithm.•Four different ...PV modules are successfully tested via double diode model.•The BPFPA method is highly convincing in accuracy to convergence at faster rate.•The proposed BPFPA provides the best performance among the other recent techniques.
The inaccurate I-V curve generation in solar PV modeling introduces less efficiency and on the other hand, accurate simulation of PV characteristics becomes a mandatory obligation before experimental validation. Although many optimization methods in literature have attempted to extract accurate PV parameters, all of these methods do not guarantee their convergence to the global optimum. Hence, the authors of this paper have proposed a new hybrid Bee pollinator Flower Pollination Algorithm (BPFPA) for the PV parameter extraction problem. The PV parameters for both single diode and double diode are extracted and tested under different environmental conditions. For brevity, the I01, I02, Ipv for double diode and I0,Ipv for single diode models are calculated analytically where the remaining parameters ‘Rs, Rp, a1, a2’ are optimized using BPFPA method. It is found that, the proposed Bee Pollinator method has all the scope to create exploration and exploitation in the control variable to yield a less RMSE value even under lower irradiated conditions. Further for performance validation, the parameters arrived via BPFPA method is compared with Genetic Algorithm (GA), Pattern Search (PS), Harmony Search (HS), Flower Pollination Algorithm (FPA) and Artificial Bee Swarm Optimization (ABSO). In addition, various outcomes of PV modeling and different parameters influencing the accurate PV modeling are critically analyzed.
Human‐mediated environmental change, by reducing mean fitness, is hypothesized to strengthen selection on traits that mediate interactions among species. For example, human‐mediated declines in ...pollinator populations are hypothesized to reduce mean seed production by increasing the magnitude of pollen limitation and thus strengthen pollinator‐mediated selection on floral traits that increase pollinator attraction or pollen transfer efficiency. To test this hypothesis, we measured two female fitness components and six floral traits of Lobelia siphilitica plants exposed to supplemental hand‐pollination, ambient open‐pollination, or reduced open‐pollination treatments. The reduced treatment simulated pollinator decline, while the supplemental treatment was used to estimate pollen limitation and pollinator‐mediated selection. We found that plants in the reduced pollination treatment were significantly pollen limited, resulting in pollinator‐mediated selection for taller inflorescences and more vibrant petals, both traits that could increase pollinator attraction. This contrasts with plants in the ambient pollination treatment, where reproduction was not pollen limited and there was not significant pollinator‐mediated selection on any floral trait. Our results support the hypothesis that human‐mediated environmental change can strengthen selection on traits of interacting species and suggest that these traits have the potential to evolve in response to changing environments.
How will native plant populations respond to declines in pollinator populations? In the bee‐pollinated wildflower Lobelia siphilitica, pollinator decline intensifies natural selection for taller inflorescences and more vibrant petals, both traits that can make plants more attractive to pollinators. Photo credit: Gavin Hossack.
Most angiosperms rely on animal pollination for reproduction, but the dependence on specific pollinator groups varies greatly between species and localities. Notably, such dependence may be ...influenced by both floral traits and environmental conditions. Despite its importance, their joint contribution has rarely been studied at the assemblage level.
At two elevations on the Caribbean island of Dominica, we measured the floral traits and the relative contributions of insects versus hummingbirds as pollinators of plants in the Rubiaceae family. Pollinator importance was measured as visitation rate (VR) and single visit pollen deposition (SVD), which were combined to assess overall pollinator effectiveness (PE).
In the wet and cool Dominican highland, we found that hummingbirds were relatively more frequent and effective pollinators than insects, whereas insects and hummingbirds were equally frequent and effective pollinators at the warmer and less rainy midelevation. Furthermore, floral traits correlated independently of environment with the relative importance of pollinators, hummingbirds being more important in plant species having flowers with long and wide corollas producing higher volumes of dilute nectar.
Our findings show that both environmental conditions and floral traits influence whether insects or hummingbirds are the most important pollinators of plants in the Rubiaceae family, highlighting the complexity of plant–pollinator systems.
Floral scent is a crucial trait for pollinator attraction. Yet only a handful of studies have estimated selection on scent in natural populations and no study has quantified the relative importance ...of pollinators and other agents of selection.
In the fragrant orchid Gymnadenia conopsea, we used electroantennographic data to identify floral scent compounds detected by local pollinators and quantified pollinator-mediated selection on emission rates of 10 target compounds as well as on flowering start, visual display and spur length.
Nocturnal pollinators contributed more to reproductive success than diurnal pollinators, but there was significant pollinator-mediated selection on both diurnal and nocturnal scent emission. Pollinators selected for increased emission of two compounds and reduced emission of two other compounds, none of which were major constituents of the total bouquet. In three cases, pollinator-mediated selection was opposed by nonpollinator-mediated selection, leading to weaker or no detectable net selection.
Our study demonstrates that minor scent compounds can be targets of selection, that pollinators do not necessarily favour stronger scent signalling, and that some scent compounds are subject to conflicting selection from pollinators and other agents of selection. Hence, including floral scent traits into selection analysis is important for understanding the mechanisms behind floral evolution.
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