Pollen Transfer Research Articles

Importance of Pollinator-Mediated Interspecific Pollen Transfer for Angiosperm Evolution

Understanding how pollen moves between species is critical to understanding speciation, diversification, and evolution of flowering plants. For co-flowering species that share pollinators, competition through interspecific pollen transfer (IPT) can profoundly impact floral evolution, decreasing female fitness via heterospecific pollen deposition on stigmas and male fitness via pollen misplacement during visits to heterospecific flowers. The pollination literature demonstrates that such reproductive interference frequently selects for reproductive character displacement in floral traits linked to pollinator attraction, pollen placement, and mating systems and has also revealed that IPT between given pairs of species is typically asymmetric. More recent work is starting to elucidate its importance to the speciation process, clarifying the link between IPT and current and historical patterns of hybridization, the evolution of phenotypic novelty through adaptive introgression, and the rise of reproductive isolation. Our review aims to stimulate further research on IPT as a ubiquitous mechanism that plays a central role in angiosperm diversification.

Bees may drive the reproduction of four sympatric cacti in a vanishing coastal mediterranean-type ecosystem.

BackgroundSympatric congeneric plants might share pollinators, or each species might avoid competition by evolving specialized traits that generate partitions in pollinator assemblages. In both cases, pollen limitation (a decrease in the quality and quantity of compatible reproductive pollen) can occur, driving the plant mating system to autogamy as a mechanism of reproductive assurance. We assessed the relationships between pollinator assemblages and mating systems in a group of sympatric congeneric plants. We attempted to answer the following questions: (i) How similar are pollinator assemblages among sympatric cactus species? (ii) Which mating systems do sympatric cactus species use?MethodsWe studied sympatric Eriosyce taxa that inhabit a threatened coastal strip in a mediterranean-type ecosystem in central Chile. We performed field observations on four taxa and characterized pollinators during the years 2016 and 2017. We estimated differences in the pollinator assemblages using the Bray–Curtis index. To elucidate the mating systems, we conducted hand-pollination experiments using three treatments: manual cross-pollination, automatic self-pollination, and control (unmanipulated individuals). We tested differences in seed production for statistical significance using Kruskal–Wallis analysis.ResultsEriosyce subgibbosa showed a distinctive pollinator assemblage among the sympatric species that we studied (similarity ranged from 0% to 8%); it was visited by small bees and was the only species that was visited by the giant hummingbird Patagona gigas. Pollinator assemblages were similar between E. chilensis (year 2016 = 4 species; 2017 = 8) and E. chilensis var. albidiflora (2016 = 7; 2017 = 4); however, those of E. curvispina var. mutabilis (2016 = 7; 2017 = 6) were less similar to those of the aforementioned species. E. curvispina var. mutabilis showed the highest interannual variation in its pollinator assemblage (18% similarity). Reproduction in E. subgibbosa largely depends on pollinators, although it showed some degree of autogamy. Autonomous pollination was unfeasible in E. chilensis, which depended on flower visitors for its reproductive success. Both E. chilensis var. albidiflora and E. curvispina var. mutabilis showed some degree of autogamy.DiscussionWe observed differences in pollinator assemblages between E. subgibbosa and the remaining Eriosyce taxa, which depend on hymenopterans for pollen transfer. Pollinator assemblages showed considerable interannual variation, especially those of E. subgibbosa (ornithophilous syndrome) and E. curvispina var. mutabilis (melitophilous syndrome). Autogamous reproduction in these taxa may act as a reproductive assurance mechanism when pollinator availability is unpredictable. Our study contributes to improving our understanding of the reproductive systems of ecological interactions between threatened species in a Chilean mediterranean-type ecosystem.

Measurement of electric charges on foraging bumblebees (Bombus terrestris)

Bumblebees carry electric charge. Almost always positive, this charge facilitates pollen transfer between bumblebee and flower during pollination and is likely to play a role in the detection of electric fields. Models of the Coulomb forces acting on pollen grains during pollination are predominantly based upon laboratory measurements of bumblebee charge. Using a novel method, the charges on bumblebees are measured outdoors for the first time. Outdoor bumblebees are found to carry similar positive charges to those previously measured in the laboratory. Bee charge is affected by local weather conditions, with the most positive charges being found on bees flying in warm, dry conditions. Results show that bee charges used in previous models of pollen transfer are representative of wild foraging bumblebees, and that pollen transfer between bee and flower is likely to be affected by local weather conditions.

Pollinator effectiveness and importance between female and male mining bee (Andrena).

Bees are often considered to be effective pollinators in both agricultural and natural ecosystems but could be ineffective pollinators in that they collect large quantities of pollen for food provision but deliver little to stigmas. Male bees do not collect pollen to feed larvae, and their pollination role has been underappreciated. Here we compare pollination effectiveness, visit frequency and pollen foraging behaviour between female and male individuals of a mining bee, Andrena emeishanica, visiting a nectariferous spring flower (Epimedium pubescens). Female bees were observed to forage for both pollen and nectar, but male bees foraged only for nectar. Female bees had large hairy hind tibiae with conspicuous scopae, and nearly 90% of the pollen grains they collected went onto the hind legs. Male bees removed less pollen from anthers than female bees but deposited more pollen on stigmas per visit. The higher pollen transfer efficiency of male bees was due to 48.4% of pollen grains remaining ungroomed on the thorax and abdomen, available for stigma contact, but their visitation rate to flowers was much lower. Our results indicate that male solitary bees could transfer more pollen on the stigma per visit but were less important (transferred less pollen in total, because they made fewer visits per unit time) than females.

Patterns and effects of heterospecific pollen transfer between an invasive and two native plant species: the importance of pollen arrival time to the stigma.

Invasive plant species can integrate into native plant-pollinator communities, but the underlying mechanisms are poorly understood. Competitive interactions between invasive and native plants via heterospecific pollen (HP) and differential invasive HP effects depending on HP arrival time to the stigma may mediate invasion success, but these have been little studied. We evaluated patterns and effects of HP receipt on pollen tube growth in two native and one invasive species in the field. We also used hand-pollination experiments to evaluate the effect of invasive HP pollen and its arrival time on native reproductive success. Native species receive smaller and less-diverse HP loads (5-7 species) compared to invasive species (10 species). The load size of HP had a negative effect on the proportion of pollen tubes in both native species but not in the invasive, suggesting higher HP tolerance in the latter. Invasive HP arrival time differentially affected pollen tube success in native species. Our results highlight the need to study reciprocal HP effects between invasive and native species and the factors that determine differential responses to HP receipt to fully understand the mechanisms facilitating invasive species integration into native plant-pollinator communities.

Geographic variation of reproductive traits and competition for pollinators in a bird-pollinated plant.

Geographic variation in the reproductive traits of animal‐pollinated plants can be shaped by spatially variable selection imposed by differences in the local pollination environment. We investigated this process in Babiana ringens (Iridaceae), an enigmatic species from the Western Cape region of South Africa. B. ringens has evolved a specialized perch facilitating cross‐pollination by sunbirds and displays striking geographic variation in perch size and floral traits. Here, we investigate whether this variation can be explained by geographic differences in the pollinator communities. We measured floral and inflorescence traits, and abiotic variables (N, P, C, and rainfall) and made observations of sunbirds in populations spanning the range of B. ringens. In each population, we recorded sunbird species identity and measured visitation rates, interfloral pollen transfer, and whether the seed set of flowers was pollen limited. To evaluate whether competition from co‐occurring sunbird‐pollinated species might reduce visitation, we quantified nectar rewards in B. ringens and of other co‐flowering bird‐pollinated species in local communities in which populations occurred. Variation in abiotic variables was not associated with geographical variation of traits in B. ringens. Malachite sunbirds were the dominant visitor (97% of visits) and populations with larger‐sized traits exhibited higher visitation rates, more between‐flower pollen transfer and set more seed. No sunbirds were observed in four populations, all with smaller‐sized traits. Sunbird visitation to B. ringens was not associated with local sunbird activity in communities, but sunbird visitation was negatively associated with the amount of B. ringens sugar relative to the availability of alternative nectar sources. Our study provides evidence that B. ringens populations with larger floral traits are visited more frequently by sunbirds, and we propose that visitation rates to B. ringens may be influenced, in part, by competition with other sunbird‐pollinated species.

Disentangling the diversity of definitions for the pollination ecosystem service and associated estimation methods

Observed declines in pollinator populations due to human pressures is of critical concern because pollination is an essential regulating ecosystem service (ES). Pollination has a major role in human food production and in maintaining flowering plant diversity. Estimating the pollination ES and its trends is thus essential for informing policy and management. However, the pollination ES remains poorly defined in practice as it is a polysemic term. In practice it is considered as: the ecosystem capacity to support pollination, the social demand for pollination or the actual pollination flow, which is the match between capacity and demand. Its quantification is complicated by the coexistence of numerous indicators. In this paper, we aimed to disentangle the diversity of definitions of the pollination service along with their associated indicators and field methods in the ecosystem service literature. From 131 reviewed papers, most studies were under temperate climate with a focus on hymenopteran pollinators, overlooking the importance of hoverflies and other dipteran pollinators. We identified four main pollination ES definitions that can be separated in two categories: (1) pollinator presence and pollen transfer, which are related to the capacity of the pollination ES; and (2) pollination success and production of fruits or seeds for human consumption, which are related to the flow of the pollination ES. Importantly, when quantified simultaneously pollination capacity and flow showed varying levels of congruence. Half of the reported relationships were congruent, but almost as many were neutral. Direct indicators of the two definitional categories characterised the respective actors of the pollination function. Studies of pollination capacity characterised pollinating agents (pollinator communities), while pollination flow studies described seeds and/or fruits produced from animal pollination. Both pollination capacity definitions share insect observations and captures as most frequent methods (70% of analysed studies), with a prevalence of indicators of pollinator diversity and abundance. Pollination flow estimation methods mainly describe the amount (number, weight) and quality of seeds/fruits. Pollinators depend on availability of feeding and nesting resources for their survival, and on their ability to reach them within landscapes. Thus, common indirect indicators of pollination are environmental variables related to semi-natural habitats and flower resources. We end this review with guidelines for relevant choices by ecosystem services scholars and practitioners of indicators and methods according to study questions and constraints (technical, financial, time and skills). Further investigations will be necessary to disentangle pollination capacity and flow relationships.

Pollen dispersal in a population of Passiflora caerulea: spatial components and ecological implications

Sexual reproduction in Angiosperms mostly depends on pollen transfer mediated by an agent. In plants pollinated by biotic agents, reproductive success and population structure are mainly determined by pollinator behavior. To further comprehend this aspect of the reproductive process, data regarding pollen transport and deposition patterns need to be gathered and analyzed. The aim of this study was to examine pollen flow dynamics in a population of the Xylocopa bee-pollinated Passiflora caerulea using fluorescent powdered dyes as pollen mimics and to analyze the relationship between inter-plant distance and fruit production. Plant arrangement, number of flowers per plant, pollen flow and fruit set exhibited leptokurtic distributions as a function of the distance between plants. Minimum and maximum dispersal distances were 4 m and 257 m, respectively. Geitonogamous transfers were more frequent than xenogamous ones. Pollinator movements, evidenced by pollen analogues transferences, responded to plant arrangement. Centris sp. was recorded for the first time as a pollinator of Passiflora caerulea. Fruit set decayed as distance between individuals increased. The tools employed allowed to better understand the dependence between plant population structure, pollinator movement, pollen flow and fruit production, as well as to generate recommendations for crop spatial design of this promising and self-incompatible species, which will counteract the effects of harvesting from the wild.

Pollen on Stigmas of Herbarium Specimens: A Window into the Impacts of a Century of Environmental Disturbance on Pollen Transfer.

Pollination is necessary for plant reproduction but often highly susceptible to disruption, for example, by habitat fragmentation and climate change. Here, we indirectly evaluated on a century timescale pollination interactions for species in one of the historically most disturbed habitats on earth-tropical dry forests of Hawai'i. We employed a novel method for acquiring a historical perspective on temporal change in pollination by characterizing pollen on stigmas of herbarium specimens from six remnant native species collected from 1909-2002. We determine whether temporal shifts occurred in (1) pollination quantity and quality or (2) the composition of species interacting via pollen transfer. While pollen quantity remained constant, these remnant species interact with different species in modern times via pollen transfer than they did nearly 100 years ago. Species that are resilient to long-term environmental change may also be the ones subject to changes in pollination interactions.

The long and short of the S-locus in Turnera (Passifloraceae).

Distyly is an intriguing floral adaptation that increases pollen transfer precision and restricts inbreeding. It has been a model system in evolutionary biology since Darwin. Although the S-locus determines the long- and short-styled morphs, the genes were unknown in Turnera. We have now identified these genes. We used deletion mapping to identify, and then sequence, BAC clones and genome scaffolds to construct S/s haplotypes. We investigated candidate gene expression, hemizygosity, and used mutants, to explore gene function. The s-haplotype possessed 21 genes collinear with a region of chromosome 7 of grape. The S-haplotype possessed three additional genes and two inversions. TsSPH1 was expressed in filaments and anthers, TsYUC6 in anthers and TsBAHD in pistils. Long-homostyle mutants did not possess TsBAHD and a short-homostyle mutant did not express TsSPH1. Three hemizygous genes appear to determine S-morph characteristics in T.subulata. Hemizygosity is common to all distylous species investigated, yet the genes differ. The pistil candidate gene, TsBAHD, differs from that of Primula, but both may inactivate brassinosteroids causing short styles. TsYUC6 is involved in auxin synthesis and likely determines pollen characteristics. TsSPH1 is likely involved in filament elongation. We propose an incompatibility mechanism involving TsYUC6 and TsBAHD.

Impact of floral characters, pollen limitation, and pollinator visitation on pollination success in different populations of Caragana korshinskii Kom

Caragana korshinskii Kom. has a significant function in desert-grassland revegetation in arid regions. Plant reproduction in arid regions can be restricted due to inadequate pollen receipt and reduced pollen transfer. An assessment of pollination success as a result of pollen limitation and pollinator visitation in various C. korshinskii populations is presently lacking. We thus tested three different treatments (pollen addition, control, and procedural control) to elucidate how pollen limitation affects seed numbers per flower in C. korshinskii. We also determined the effect of pollinator visit frequency on seeds per flower. Our results demonstrated that there was a higher proportion of open flowers and mature fruits in the managed population than in the natural population. Pollen addition significantly increased seed number per flower, and pollen limitation was determined to be a significant limiting factor in seed production. Furthermore, Apis mellifera was determined to be the principal pollinator, and pollinator visitation frequency was significantly correlated with open flower number. Our findings also demonstrated that pollinator visitation rate and seed production were positively correlated. Management and pollinator visitation could affect seed production, which may explain the higher seeds per flower in the managed population compared with the natural population.

Avoiding sexual interference: herkogamy and dichogamy in style dimorphic flowers of Narcissus broussonetii (Amaryllidaceae).

Spatial (herkogamy) or temporal (dichogamy) separation of sex organs are mechanisms considered to restrict self-pollination and promote outcrossing. Additionally, avoidance of self-interference is proposed to be the driving force for the evolution of these mechanisms, particularly in self-incompatible species. However, species with anthers and stigmas at different levels may increase the rate of imprecise pollen transfer, resulting in pollen discounting. Non-reciprocal stylar dimorphism has been considered a transitional, unstable stage towards the evolution of reciprocal style dimorphism (distyly), to simultaneously avoid interference and lack of precision. In this study we investigate the spatial and temporal separation of sex organs in a population of the style dimorphic and self-incompatible Narcissus broussonetii and their consequences in the reciprocity between the sex organs of morphs and their fecundity. First, we evaluated the relative growth of sex organs after anthesis. Then, we studied the stigma receptivity along the flower lifespan including its effect on seed production in both morphs. Finally, given the weak reciprocity between the sex organs of morphs of this species, we estimated population genetic diversity parameters in Long- and Short-styled plants to explore differences between them as a result of rates of inbreeding due to different mating strategies. We observed that Long-styled plants and Short-styled plants present different strategies to avoid sexual interference and both of them had negative consequences in the reciprocity between the sex organs of morphs. Long-styled plants exhibited a delay in stigma receptivity and a higher growth rate of the style after anthesis, while Short-styled plants presented higher herkogamy and no delay in stigma receptivity. These findings suggest that the avoidance of self-interference, in stylar dimorphic Narcissus species, seems to be more critical than improving of reciprocity between the sex organs of morphs. This might explain why reciprocal herkogamy (distyly) is rare in the genus.

Generalist birds outperform specialist sunbirds as pollinators of an AfricanAloe

Bird pollination systems are dominated by specialist nectarivores, such as hummingbirds in the Americas and sunbirds in Africa. Opportunistic (generalist) avian nectarivores such as orioles, weavers and bulbuls have also been implicated as plant pollinators, but their effectiveness as agents of pollen transfer is poorly known. Here, we compare the single-visit effectiveness of specialist and opportunistic avian nectarivores as pollinators of Aloe ferox, a plant that relies almost exclusively on birds for seed production. We found that the number of pollen grains on stigmas of flowers receiving single visits by opportunistic avian nectarivores was approximately threefold greater than on those receiving single visits by specialist sunbirds and about twofold greater than on those that received single visits by honeybees. The number of pollen grains on stigmas of flowers visited by sunbirds was similar to that on stigmas of unvisited flowers. These results show that opportunistic birds are highly effective pollinators of A. ferox, supporting the idea that some plants are specialized for pollination by opportunistic birds.

Reproductive isolation among three sympatric Achimenes species: pre- and post-pollination components.

Closely related species occurring in sympatry may experience the negative consequences of interspecific pollen transfer if reproductive isolation (RI) barriers are not in place. We evaluated the importance of pre- and post-pollination RI barriers in three sympatric species of Achimenes (Gesneriaceae), including ecogeographic, phenological, floral isolation, self-pollination, and hybrid viability (fruit and seed set). We recorded geographic distribution throughout species ranges and assessed flowering phenology and pollinator visitation at one site in central Mexico. In the greenhouse, we measured floral traits involved in RI and quantified fruit and seed set for from self, intraspecific, and interspecific crosses. Ecogeographic barriers were important in RI, but under sympatry, phenological and floral barriers contributed more to total RI. Phenological RI varied between species and years, while floral RI was 100% effective at preventing interspecific visitation. Species showed differences in floral morphology, color, and scents associated with specialized pollination systems (A. antirrhina-hummingbirds, A. flava-bees, A. patens-butterflies); heterospecific visitation events were restricted to rare secondary pollinators. Hybrid crosses consistently yielded progeny in lower numbers than intraspecific crosses. This study indicated that neither autogamy nor early post-pollination barriers prevent interspecific pollen flow between Achimenes species. However, floral isolation, acting through a combination of attraction and reward traits, consistently ensures specificity of the pollination system. These results suggest that selection on floral traits to reduce the costs of hybrid progeny production may have played a role in evolution or maintenance of specialized pollination systems in Achimenes.

Mass Seasonal Migrations of Hoverflies Provide Extensive Pollination and Crop Protection Services

Despite the fact that migratory insects dominate aerial bioflows in terms of diversity, abundance, and biomass [1-6], the migration patterns of most species, and the effects of their annual fluxes between high- and low-latitude regions, are poorly known. One important group of long-range migrants that remain understudied is a suite of highly beneficial species of hoverfly in the tribe Syrphini, which we collectively term "migrant hoverflies." Adults are key pollinators [7-10] and larvae are significant biocontrol agents of aphid crop pests [11], and thus, it is important to quantify the scale of their migrations and the crucial ecosystem services they provide with respect to energy, nutrient, and biomass transport; regulation of crop pests; and pollen transfer. Such assessments cannot be made by sporadic observations of mass arrivals at ground level, because hoverflies largely migrate unnoticed high above ground. We used insect-monitoring radars [12] to show that up to 4 billion hoverflies (80tons of biomass) travel high above southern Britain each year in seasonally adaptive directions. The long-range migrations redistribute tons of essential nutrients (nitrogen [N] and phosphorus [P]) and transport billions of pollen grains between Britain and Europe, and locally produced populations consume 6 trillion aphids and make billions of flower visits. Migrant hoverfly abundance fluctuated greatly between years, but there was no evidence of a population trend during the 10-year study period. Considering that many beneficial insects are seriously declining [7, 10, 13-19], our results demonstrate that migrant hoverflies arekey to maintaining essential ecosystem services.

Elaborated pollen packaging and dispensing mechanism induced by petal architecture from a Papaveraceae species.

Secondary pollen presentation (SPP) is a reproductive strategy that enhances the efficiency of pollen transfer, which has been explored for more than 200 years, resulting in 10 identified types of SPP. The ephemeral plant Hypecoum erectum L. (Papaveraceae) has an elaborate petal structure. The middle lobe is a key functional organ in SPP. To explore the importance of the middle lobe structure, we measured the flowering process, the curling movement and growth of the middle lobe, pollination characteristics, pollination efficiency, and the mating system in H. erectum in the field. The yellow middle lobe structure had an important role in attracting pollinators. The middle lobes on the inner petals function as a redundant cucullate structure and wrapped about 84% of the total pollen grains as soon as the anthers dehisced. These then grew upward and gradually presented pollen to pollinators via the roll out of the middle lobes. One bee species, Colletes vestitus from Colletidae, was the only effective pollinator of H. erectum. The SPP mechanism increased the efficiency of pollen transfer by C. vestitus. The middle lobes, which wrapped pollen and grew upward, contacted the stigma and provided an advantage for self-pollination and outcrossing by growing upward higher than the corolla. Hypecoum erectum L. has a mixed mating system with selfing and outcrossing. Thus, the SPP mechanism plays a key role during the pollination process and is necessary for improving pollination efficiency and promoting reproductive success.

Floral isolation and pollination in two hummingbird-pollinated plants: the roles of exploitation barriers and pollinator competition

Differences in feeding performance and aggressive abilities between species and sexes of hummingbirds are often associated with the partitioning of their food sources, but whether such partitioning results in floral isolation (reproductive isolation at the stage of pollination) has received little attention. We examined components of floral isolation and pollinator effectiveness of Heliconia caribaea and H. bihai on the island of Dominica, West Indies. The short flowers of H. caribaea match the short bills of male Anthracothorax jugularis, its primary pollinator, whereas the long flowers of H. bihai match the long bills of female A. jugularis, its primary pollinator. In pollination experiments, both sexes of A. jugularis were equally effective at pollinating the short flowers of H. caribaea, which they preferred to H. bihai, whereas females were more effective at pollinating the long flowers of H. bihai. Moreover, an average difference in length of 12 mm between H. caribaea and H. bihai flowers did not prevent heterospecific pollen transfer, and both sexes transported pollen between the two plant species. In field studies using powdered dyes as pollen analogs, however, heterospecific pollen transfer was minimal, with only 2 of 168 flowers receiving dye from the other species. The length of H. bihai flowers acted as an exploitation barrier to male A. jugularis, which were unable to completely remove nectar from 88% of the flowers they visited. In contrast, interference competition combined with high floral fidelity through traplining prevented female A. jugularis from transferring pollen between the two Heliconia species. A combination of exploitation barriers, interference and exploitative competition, and pollinator preferences maintains floral isolation between these heliconias, and may have contributed to the evolution of this hummingbird-plant system.

Extraction of the PV modules parameters with MPP estimation using the modified flower algorithm

Modeling of photovoltaic (PV) module remains a serious issue for a lot of applications such as monitoring system or fault detection system. Therefore, several equivalents models of the PV cell have been proposed, the famous proposed models are called the single diode model (SDM) and double diode model (DDM). Each model possesses unknown parameters values which must be defined. In the present paper, two electrical models equivalent to PV cell are proposed, these models have an unknowns parameters which must be identified. The modified flower algorithm (MFA) is an optimization algorithm inspired from the nature, this algorithm is used to extract the optimal parameters values for both models. The proposed algorithm mimics the pathways of pollen transfer to help produce plants in nature, in other words, there are a lot of ways that the pollen can be travel to reproduce the plants these ways can be developed to a powerful optimization algorithm. In order to assess the proposed algorithm, several experimental data are used, these data are acquired in outdoors conditions and contains various I-V curves, these I-V curves are taken from three kind of PV cell technologies which namely Monocrystalline, Polycrystalline and Amorphous. In addition, the simulation results are compared with experimental data for both models. Moreover, the identified SDM parameters are applied to predict the current, the voltage and the power at the maximum power point (MPP) which was then compared to the MPP obtained from real data of grid connected photovoltaic system (GCPVS).

Global geographic patterns of heterospecific pollen receipt help uncover potential ecological and evolutionary impacts across plant communities worldwide

Species interactions are known to be key in driving patterns of biodiversity across the globe. Plant-plant interactions through heterospecific pollen (HP) transfer by their shared pollinators is common and has consequences for plant reproductive success and floral evolution, and thus has the potential to influence global patterns of biodiversity and plant community assembly. The literature on HP transfer is growing and it is therefore timely to review patterns and causes of among-species variation in HP receipt at a global scale, thus uncovering its potential contribution to global patterns of biodiversity. Here we analyzed published data on 245 species distributed across five continents to evaluate latitudinal and altitudinal patterns of HP receipt. We further analyzed the role of floral symmetry and evolutionary history in mediating patterns of HP receipt. Latitude and elevation affected the likelihood and intensity of HP receipt indicating that HP transfer increases in species-rich communities and in areas with high abundance of vertebrate pollinators. Floral symmetry and evolutionary history determined HP load size across plant communities worldwide. Overall, our results suggest that HP receipt may have the potential to contribute to global geographic patterns of plant diversity by imposing strong selective pressures in species-rich areas across the globe.

Disentangling the pollination system of the food-deceptive orchid Anacamptis longicornu (Orchidaceae): from breeding system to spatio-temporal variation in reproductive success

The deceptive breeding system in the Orchidaceae family has been studied for decades to disentangle how pollination service can occur. Moreover, the interference of introduced herbivores on population development has been reported to affect the reproductive output in different plant species, including orchids. In this study, the breeding system of the food-deceptive species Anacamptis longicornu has been assessed. The spatio-temporal variation in both male and female reproductive fitness and its relationship with plant features were also analyzed. The possible herbivory effects were investigated by an exclusion experiment using two types of cages. The results confirm that this species is pollinator dependent and mostly allogamous but is also self-compatible. This species showed high values of cumulative inbreeding depression index for fruit set and seed viability parameters and was highly pollen-limited. Male fitness was always higher than female fitness between years and locations, and both parameters showed spatio-temporal variation. The use of cages excluded herbivores but, eventually, also excluded pollinators, so that both male and female reproductive success parameters decreased significantly in the complete exclusion treatment. The strong dependence of the species’ fitness on pollinator-mediated pollen transfer must be considered for the long-term conservation of A. longicornu.