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1.
Cell ; 183(4): 875-889.e17, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-33035453

RESUMO

Banyan trees are distinguished by their extraordinary aerial roots. The Ficus genus includes species that have evolved a species-specific mutualism system with wasp pollinators. We sequenced genomes of the Chinese banyan tree, F. microcarpa, and a species lacking aerial roots, F. hispida, and one wasp genome coevolving with F. microcarpa, Eupristina verticillata. Comparative analysis of the two Ficus genomes revealed dynamic karyotype variation associated with adaptive evolution. Copy number expansion of auxin-related genes from duplications and elevated auxin production are associated with aerial root development in F. microcarpa. A male-specific AGAMOUS paralog, FhAG2, was identified as a candidate gene for sex determination in F. hispida. Population genomic analyses of Ficus species revealed genomic signatures of morphological and physiological coadaptation with their pollinators involving terpenoid- and benzenoid-derived compounds. These three genomes offer insights into and genomic resources for investigating the geneses of aerial roots, monoecy and dioecy, and codiversification in a symbiotic system.


Assuntos
Evolução Biológica , Ficus/genética , Genoma de Planta , Polinização/fisiologia , Árvores/genética , Vespas/fisiologia , Animais , Cromossomos de Plantas/genética , Elementos de DNA Transponíveis/genética , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Ácidos Indolacéticos/metabolismo , Anotação de Sequência Molecular , Filogenia , Raízes de Plantas/crescimento & desenvolvimento , Duplicações Segmentares Genômicas/genética , Cromossomos Sexuais/genética , Compostos Orgânicos Voláteis/análise
2.
Nature ; 628(8007): 342-348, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38538790

RESUMO

Climate change could pose an urgent threat to pollinators, with critical ecological and economic consequences. However, for most insect pollinator species, we lack the long-term data and mechanistic evidence that are necessary to identify climate-driven declines and predict future trends. Here we document 16 years of abundance patterns for a hyper-diverse bee assemblage1 in a warming and drying region2, link bee declines with experimentally determined heat and desiccation tolerances, and use climate sensitivity models to project bee communities into the future. Aridity strongly predicted bee abundance for 71% of 665 bee populations (species × ecosystem combinations). Bee taxa that best tolerated heat and desiccation increased the most over time. Models forecasted declines for 46% of species and predicted more homogeneous communities dominated by drought-tolerant taxa, even while total bee abundance may remain unchanged. Such community reordering could reduce pollination services, because diverse bee assemblages typically maximize pollination for plant communities3. Larger-bodied bees also dominated under intermediate to high aridity, identifying body size as a valuable trait for understanding how climate-driven shifts in bee communities influence pollination4. We provide evidence that climate change directly threatens bee diversity, indicating that bee conservation efforts should account for the stress of aridity on bee physiology.


Assuntos
Abelhas , Mudança Climática , Dessecação , Ecossistema , Temperatura Alta , Animais , Abelhas/anatomia & histologia , Abelhas/classificação , Abelhas/fisiologia , Biodiversidade , Tamanho Corporal/fisiologia , Aquecimento Global , Modelos Biológicos , Plantas , Polinização/fisiologia , Masculino , Feminino
3.
Plant J ; 119(1): 56-64, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38581375

RESUMO

Food security is threatened by climate change, with heat and drought being the main stresses affecting crop physiology and ecosystem services, such as plant-pollinator interactions. We hypothesize that tracking and ranking pollinators' preferences for flowers under environmental pressure could be used as a marker of plant quality for agricultural breeding to increase crop stress tolerance. Despite increasing relevance of flowers as the most stress sensitive organs, phenotyping platforms aim at identifying traits of resilience by assessing the plant physiological status through remote sensing-assisted vegetative indexes, but find strong bottlenecks in quantifying flower traits and in accurate genotype-to-phenotype prediction. However, as the transport of photoassimilates from leaves (sources) to flowers (sinks) is reduced in low-resilient plants, flowers are better indicators than leaves of plant well-being. Indeed, the chemical composition and amount of pollen and nectar that flowers produce, which ultimately serve as food resources for pollinators, change in response to environmental cues. Therefore, pollinators' preferences could be used as a measure of functional source-to-sink relationships for breeding decisions. To achieve this challenging goal, we propose to develop a pollinator-assisted phenotyping and selection platform for automated quantification of Genotype × Environment × Pollinator interactions through an insect geo-positioning system. Pollinator-assisted selection can be validated by metabolic, transcriptomic, and ionomic traits, and mapping of candidate genes, linking floral and leaf traits, pollinator preferences, plant resilience, and crop productivity. This radical new approach can change the current paradigm of plant phenotyping and find new paths for crop redomestication and breeding assisted by ecological decisions.


Assuntos
Produtos Agrícolas , Flores , Fenótipo , Melhoramento Vegetal , Polinização , Estresse Fisiológico , Polinização/fisiologia , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Melhoramento Vegetal/métodos , Flores/fisiologia , Flores/genética , Animais , Genótipo
4.
Plant Physiol ; 195(1): 343-355, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38270530

RESUMO

Flowering plants contain tightly controlled pollen-pistil interactions required for promoting intraspecific fertilization and preventing interspecific hybridizations. In Arabidopsis (Arabidopsis thaliana), several receptor kinases (RKs) are known to regulate the later stages of intraspecific pollen tube growth and ovular reception in the pistil, but less is known about RK regulation of the earlier stages. The Arabidopsis RECEPTOR-LIKE KINASE IN FLOWERS1 (RKF1)/RKF1-LIKE (RKFL) 1-3 cluster of 4 leucine-rich repeat malectin (LRR-MAL) RKs was previously found to function in the stigma to promote intraspecific pollen hydration. In this study, we tested additional combinations of up to 7 Arabidopsis LRR-MAL RK knockout mutants, including RKF1, RKFL1-3, LysM RLK1-INTERACTING KINASE1, REMORIN-INTERACTING RECEPTOR1, and NEMATODE-INDUCED LRR-RLK2. These LRR-MAL RKs were discovered to function in the female stigma to support intraspecific Arabidopsis pollen tube growth and to establish a prezygotic interspecific barrier against Capsella rubella pollen. Thus, this study uncovered additional biological functions for this poorly understood group of RKs in regulating the early stages of Arabidopsis sexual reproduction.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Flores , Tubo Polínico , Pólen , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Flores/genética , Flores/fisiologia , Pólen/genética , Pólen/fisiologia , Pólen/crescimento & desenvolvimento , Tubo Polínico/genética , Tubo Polínico/crescimento & desenvolvimento , Polinização/fisiologia , Capsella/genética , Capsella/fisiologia , Capsella/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas Quinases/metabolismo , Proteínas Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas de Repetições Ricas em Leucina
5.
PLoS Comput Biol ; 20(1): e1011762, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38194414

RESUMO

Plant and pollinator communities are vital for transnational food chains. Like many natural systems, they are affected by global change: rapidly deteriorating conditions threaten their numbers. Previous theoretical studies identified the potential for community-wide collapse above critical levels of environmental stressors-so-called bifurcation-induced tipping points. Fortunately, even as conditions deteriorate, individuals have some adaptive capacity, potentially increasing the boundary for a safe operating space where changes in ecological processes are reversible. Our study considers this adaptive capacity of pollinators to resource availability and identifies a new threat to disturbed pollinator communities. We model the adaptive foraging of pollinators in changing environments. Pollinator's adaptive foraging alters the dynamical responses of species, to the advantage of some-typically generalists-and the disadvantage of others, with systematic non-linear and non-monotonic effects on the abundance of particular species. We show that, in addition to the extent of environmental stress, the pace of change of environmental stress can also lead to the early collapse of both adaptive and nonadaptive pollinator communities. Specifically, perturbed communities exhibit rate-induced tipping points at stress levels within the safe boundary defined for constant stressors. With adaptive foraging, tipping is a more asynchronous collapse of species compared to nonadaptive pollinator communities, meaning that not all pollinator species reach a tipping event simultaneously. These results suggest that it is essential to consider the adaptive capacity of pollinator communities for monitoring and conservation. Both the extent and the rate of stress change relative to the ability of communities to recover are critical environmental boundaries.


Assuntos
Modelos Biológicos , Polinização , Humanos , Polinização/fisiologia , Modelos Teóricos , Plantas , Cadeia Alimentar
6.
Proc Natl Acad Sci U S A ; 119(5)2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35074876

RESUMO

Nearly 90% of flowering plants depend on animals for reproduction. One of the main rewards plants offer to pollinators for visitation is nectar. Nesocodon mauritianus (Campanulaceae) produces a blood-red nectar that has been proposed to serve as a visual attractant for pollinator visitation. Here, we show that the nectar's red color is derived from a previously undescribed alkaloid termed nesocodin. The first nectar produced is acidic and pale yellow in color, but slowly becomes alkaline before taking on its characteristic red color. Three enzymes secreted into the nectar are either necessary or sufficient for pigment production, including a carbonic anhydrase that increases nectar pH, an aryl-alcohol oxidase that produces a pigment precursor, and a ferritin-like catalase that protects the pigment from degradation by hydrogen peroxide. Our findings demonstrate how these three enzymatic activities allow for the condensation of sinapaldehyde and proline to form a pigment with a stable imine bond. We subsequently verified that synthetic nesocodin is indeed attractive to Phelsuma geckos, the most likely pollinators of Nesocodon We also identify nesocodin in the red nectar of the distantly related and hummingbird-visited Jaltomata herrerae and provide molecular evidence for convergent evolution of this trait. This work cumulatively identifies a convergently evolved trait in two vertebrate-pollinated species, suggesting that the red pigment is selectively favored and that only a limited number of compounds are likely to underlie this type of adaptation.


Assuntos
Flores/metabolismo , Magnoliopsida/metabolismo , Pigmentação/fisiologia , Néctar de Plantas/metabolismo , Pólen/metabolismo , Adaptação Fisiológica/fisiologia , Animais , Aves/fisiologia , Lagartos/fisiologia , Polinização/fisiologia , Reprodução/fisiologia
7.
Ecol Lett ; 27(1): e14368, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38247047

RESUMO

Determining how and why organisms interact is fundamental to understanding ecosystem responses to future environmental change. To assess the impact on plant-pollinator interactions, recent studies have examined how the effects of environmental change on individual interactions accumulate to generate species-level responses. Here, we review recent developments in using plant-pollinator networks of interacting individuals along with their functional traits, where individuals are nested within species nodes. We highlight how these individual-level, trait-based networks connect intraspecific trait variation (as frequency distributions of multiple traits) with dynamic responses within plant-pollinator communities. This approach can better explain interaction plasticity, and changes to interaction probabilities and network structure over spatiotemporal or other environmental gradients. We argue that only through appreciating such trait-based interaction plasticity can we accurately forecast the potential vulnerability of interactions to future environmental change. We follow this with general guidance on how future studies can collect and analyse high-resolution interaction and trait data, with the hope of improving predictions of future plant-pollinator network responses for targeted and effective conservation.


Assuntos
Ecossistema , Polinização , Humanos , Polinização/fisiologia , Plantas , Fenótipo
8.
Planta ; 260(1): 15, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38829528

RESUMO

MAIN CONCLUSION: One of seven Solanum taxa studied displayed associations between pollen presence and floral scent composition and volume, suggesting buzz-pollinated plants rarely use scent as an honest cue for foraging pollinators. Floral scent influences the recruitment, learning, and behaviour of floral visitors. Variation in floral scent can provide information on the amount of reward available or whether a flower has been visited recently and may be particularly important in species with visually concealed rewards. In many buzz-pollinated flowers, tubular anthers opening via small apical pores (poricidal anthers) visually conceal pollen and appear similar regardless of pollen quantity within the anther. We investigated whether pollen removal changes floral scent composition and emission rate in seven taxa of buzz-pollinated Solanum (Solanaceae). We found that pollen removal reduced both the overall emission of floral scent and the emission of specific compounds (linalool and farnesol) in S. lumholtzianum. Our findings suggest that in six out of seven buzz-pollinated taxa studied here, floral scent could not be used as a signal by visitors as it does not contain information on pollen availability.


Assuntos
Flores , Odorantes , Pólen , Polinização , Solanum , Solanum/fisiologia , Solanum/química , Polinização/fisiologia , Flores/fisiologia , Flores/química , Pólen/fisiologia , Pólen/química , Odorantes/análise , Animais , Abelhas/fisiologia
9.
New Phytol ; 243(4): 1600-1609, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38937955

RESUMO

Pollination presents a risky journey for pollen grains. Pollen loss is sometimes thought to favour greater pollen investment to compensate for the inefficiency of transport. Sex allocation theory, to the contrary, has consistently concluded that postdispersal loss should have no selective effect on investment in either sex function. But the intuitively appealing compensation idea continues to be raised despite the lack of theoretical endorsement. We address the theoretical issue with a model that directly represents pollen loss (and ovule loss through floral demise or loss of receptivity) as rate-dependent dynamical processes. These loss rates can be varied to examine the effect of pollination efficiency on optimal sex allocation. Pollen-ovule ratios follow from the sex allocation based on the resource costs of pollen and ovule production. This model confirms conventional findings that pollen loss should have essentially no effect on sexual resource allocation in large, panmictic populations. Pollen limitation of seed set does not alter this conclusion. These results force us to rethink the empirical association of pollination efficiency with low pollen-ovule ratios. This pattern could arise if efficient pollen transport commonly results in stigmatic deposition of cohorts of related pollen. Empirical evidence of correlated paternity supports this explanation.


Assuntos
Modelos Biológicos , Óvulo Vegetal , Pólen , Polinização , Pólen/fisiologia , Polinização/fisiologia , Óvulo Vegetal/fisiologia
10.
New Phytol ; 243(4): 1586-1599, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38724032

RESUMO

Mycorrhizal symbiosis, seed dispersal, and pollination are recognized as the most prominent mutualistic interactions in terrestrial ecosystems. However, it remains unclear how these symbiotic relationships have interacted to contribute to current plant diversity. We analyzed evolutionary relationships among mycorrhizal type, seed dispersal mode, and pollination mode in two global databases of 699 (database I) and 10 475 (database II) tree species. Although database II had been estimated from phylogenetic patterns and therefore had lower certainty of the mycorrhizal type than database I, whose mycorrhizal type was determined by direct observation, database II allowed analysis of many more taxa from more regions than database I. We found evidence of joint evolution of all three features in both databases. This result is robust to the effects of both sampling bias and missing taxa. Most arbuscular mycorrhizal-associated trees had endozoochorous (biotic) seed dispersal and biotic pollination, with long dispersal distances, whereas most ectomycorrhizal-associated trees had anemochorous (abiotic) seed dispersal and wind (abiotic) pollination mode, with shorter dispersal distances. These results provide a novel scenario in mutualistic interactions, seed dispersal, pollination, and mycorrhizal symbiosis types, which have jointly evolved and shaped current tree diversity and forest ecosystem world-wide.


Assuntos
Evolução Biológica , Micorrizas , Polinização , Dispersão de Sementes , Simbiose , Árvores , Micorrizas/fisiologia , Simbiose/fisiologia , Polinização/fisiologia , Dispersão de Sementes/fisiologia , Árvores/microbiologia , Árvores/fisiologia , Filogenia
11.
New Phytol ; 242(6): 2888-2899, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38622779

RESUMO

Plant pollen is rich in protein, sterols and lipids, providing crucial nutrition for many pollinators. However, we know very little about the quantity, quality and timing of pollen availability in real landscapes, limiting our ability to improve food supply for pollinators. We quantify the floral longevity and pollen production of a whole plant community for the first time, enabling us to calculate daily pollen availability. We combine these data with floral abundance and nectar measures from UK farmland to quantify pollen and nectar production at the landscape scale throughout the year. Pollen and nectar production were significantly correlated at the floral unit, and landscape level. The species providing the highest quantity of pollen on farmland were Salix spp. (38%), Filipendula ulmaria (14%), Rubus fruticosus (10%) and Taraxacum officinale (9%). Hedgerows were the most pollen-rich habitats, but permanent pasture provided the majority of pollen at the landscape scale, because of its large area. Pollen and nectar were closely associated in their phenology, with both peaking in late April, before declining steeply in June and remaining low throughout the year. Our data provide a starting point for including pollen in floral resource assessments and ensuring the nutritional requirements of pollinators are met in farmland landscapes.


Assuntos
Néctar de Plantas , Pólen , Pólen/fisiologia , Fazendas , Flores/fisiologia , Estações do Ano , Polinização/fisiologia , Ecossistema
12.
New Phytol ; 242(5): 2312-2321, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38561636

RESUMO

Across temperate forests, many tree species produce flowers before their leaves emerge. This flower-leaf phenological sequence, known as hysteranthy, is generally described as an adaptation for wind pollination. However, this explanation does not address why hysteranthy is also common in biotically pollinated taxa. We quantified flower-leaf sequence variation in the American plums (Prunus, subg. Prunus sect. Prunocerasus), a clade of insect-pollinated trees, using herbaria specimens and Bayesian hierarchical modeling. We tested two common, but rarely interrogated hypotheses - that hysteranthy confers aridity tolerance and/or pollinator visibility - by modeling the associations between hysteranthy and related traits. To understand how these phenology-trait associations were sensitive to taxonomic scale and flower-leaf sequence classification, we then extended these analyses to all Prunus species in North America. Our findings across two taxonomic levels support the hypotheses that hysteranthy may help temporally partition hydraulic demand to reduce water stress and increase pollinator visibility - thereby reducing selective pressure on inflorescence size. Our results provide foundational insights into the evolution of flower-leaf sequences in the genus Prunus, with implications for understanding these patterns in biotically pollinated plants in general. Our approach suggests a path to advance these hypotheses to other clades, but teasing out drivers fully will require new experiments.


Assuntos
Flores , Folhas de Planta , Polinização , Prunus , Flores/fisiologia , Polinização/fisiologia , Folhas de Planta/fisiologia , Prunus/fisiologia , Prunus/genética , Animais , Teorema de Bayes
13.
New Phytol ; 243(5): 2008-2020, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38952269

RESUMO

The diversity of plant-pollinator interactions is grounded in floral resources, with nectar considered one of the main floral rewards plants produce for pollinators. However, a global evaluation of the number of animal-pollinated nectar-producing angiosperms and their distribution world-wide remains elusive. We compiled a thorough database encompassing 7621 plant species from 322 families to estimate the number and proportion of nectar-producing angiosperms reliant on animal pollination. Through extensive sampling of plant communities, we also explored the interplay between nectar production, floral resource diversity, latitudinal and elevational gradients, contemporary climate, and environmental characteristics. Roughly 223 308 animal-pollinated angiosperms are nectar-producing, accounting for 74.4% of biotic-pollinated species. Global distribution patterns of nectar-producing plants reveal a distinct trend along latitudinal and altitudinal gradients, with increased proportions of plants producing nectar in high latitudes and altitudes. Conversely, tropical communities in warm and moist climates exhibit greater floral resource diversity and a lower proportion of nectar-producing plants. These findings suggest that ecological trends driven by climate have fostered the diversification of floral resources in warmer and less seasonal climates, reducing the proportion of solely nectar-producing plants. Our study provides a baseline for understanding plant-pollinator relationships, plant diversification, and the distribution of plant traits.


Assuntos
Magnoliopsida , Néctar de Plantas , Polinização , Néctar de Plantas/metabolismo , Polinização/fisiologia , Magnoliopsida/fisiologia , Animais , Altitude , Flores/fisiologia , Clima , Geografia
14.
New Phytol ; 243(4): 1571-1585, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38922897

RESUMO

Increased temperature can induce plastic changes in many plant traits. However, little is known about how these changes affect plant interactions with insect pollinators and herbivores, and what the consequences for plant fitness and selection are. We grew fast-cycling Brassica rapa plants at two temperatures (ambient and increased temperature) and phenotyped them (floral traits, scent, colour and glucosinolates). We then exposed plants to both pollinators (Bombus terrestris) and pollinating herbivores (Pieris rapae). We measured flower visitation, oviposition of P. rapae, herbivore development and seed output. Plants in the hot environment produced more but smaller flowers, with lower UV reflectance and emitted a different volatile blend with overall lower volatile emission. Moreover, these plants received fewer first-choice visits by bumblebees and butterflies, and fewer flower visits by butterflies. Seed production was lower in hot environment plants, both because of a reduction in flower fertility due to temperature and because of the reduced visitation of pollinators. The selection on plant traits changed in strength and direction between temperatures. Our study highlights an important mechanism by which global warming can change plant-pollinator interactions and negatively impact plant fitness, as well as potentially alter plant evolution through changes in phenotypic selection.


Assuntos
Brassica rapa , Borboletas , Flores , Aptidão Genética , Temperatura Alta , Polinização , Polinização/fisiologia , Animais , Flores/fisiologia , Abelhas/fisiologia , Brassica rapa/fisiologia , Borboletas/fisiologia , Herbivoria/fisiologia , Sementes/fisiologia , Compostos Orgânicos Voláteis/metabolismo , Compostos Orgânicos Voláteis/análise , Fenótipo , Oviposição/fisiologia , Temperatura , Característica Quantitativa Herdável
15.
New Phytol ; 243(2): 753-764, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38714871

RESUMO

Plants can evolve rapidly after pollinator changes, but the response of different floral traits to novel selection can vary. Floral morphology is often expected to show high integration to maintain pollination accuracy, while nectar traits can be more environmentally sensitive. The relative role of genetic correlations and phenotypic plasticity (PP) in floral evolution remains unclear, particularly for nectar traits, and can be studied in the context of recent pollinator changes. Digitalis purpurea shows rapid recent evolution of corolla morphology but not nectar traits following a range expansion with hummingbirds added as pollinators. We use this species to compare PP, heritability, evolvability and integration of floral morphology and nectar in a common garden. Morphological traits showed higher heritability than nectar traits, and the proximal section of the corolla, which regulates access to nectar and underwent rapid change in introduced populations, presented lower integration than the rest of the floral phenotype. Nectar was more plastic than morphology, driven by highly plastic sugar concentration. Nectar production rate showed high potential to respond to selection. These results explain the differential rapid evolution of floral traits previously observed in this species and show how intrafloral modularity determines variable evolutionary potential in morphological and nectar traits.


Assuntos
Evolução Biológica , Flores , Fenótipo , Néctar de Plantas , Polinização , Flores/anatomia & histologia , Flores/fisiologia , Polinização/fisiologia , Característica Quantitativa Herdável , Meio Ambiente , Animais , Aves/anatomia & histologia , Aves/fisiologia
16.
New Phytol ; 243(1): 440-450, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38655668

RESUMO

Hybrid zones provide natural experimental settings to test hypotheses about species divergence. We concentrated on a hybrid swarm in which oil-collecting bees and flower-pecking birds act as pollinators of two Calceolaria species. We asked whether both pollinators contributed to flower divergence by differentially promoting prezygotic fitness at the phenotypic extremes that represent parentals. We studied pollinator-mediated selection on phenotypic traits critical in plant-pollinator mechanical interaction, namely plant height, reward-to-stigma distance, and flower shape. We utilised the quantity and quality of pollen deposited as fitness measures and distinguished between the contribution of the two pollinator types. Results showed uni- and bivariate disruptive selection for most traits through pollen grains deposited by both pollinators. Bird-mediated fitness favoured low plants with a long reward-to-stigma distance and a straight corolla, while bee-mediated fitness favoured tall plants with a short reward-to-stigma distance and curved corolla. In addition, stabilising selection at one end of the phenotypic range showed a bird-mediated reproductive asymmetry within the swarm. The disruptive pattern was countered, albeit weakly, by hybrids receiving higher-quality pollen on the stigmas. Results suggest that pollinator-mediated selection promotes divergence of integrated flower phenotypes mechanically adjusted either to bees or birds underscoring the importance of pollinator specialisation in diversification.


Assuntos
Flores , Aptidão Genética , Fenótipo , Polinização , Seleção Genética , Polinização/fisiologia , Animais , Abelhas/fisiologia , Flores/fisiologia , Flores/anatomia & histologia , Aves/fisiologia , Pólen/fisiologia , Hibridização Genética , Especificidade da Espécie
17.
New Phytol ; 242(5): 2322-2337, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38634161

RESUMO

Shifts among functional pollinator groups are commonly regarded as sources of floral morphological diversity (disparity) through the formation of distinct pollination syndromes. While pollination syndromes may be used for predicting pollinators, their predictive accuracy remains debated, and they are rarely used to test whether floral disparity is indeed associated with pollinator shifts. We apply classification models trained and validated on 44 functional floral traits across 252 species with empirical pollinator observations and then use the validated models to predict pollinators for 159 species lacking observations. In addition, we employ multivariate statistics and phylogenetic comparative analyses to test whether pollinator shifts are the main source of floral disparity in Melastomataceae. We find strong support for four well-differentiated pollination syndromes ('buzz-bee', 'nectar-foraging vertebrate', 'food-body-foraging vertebrate', 'generalist'). While pollinator shifts add significantly to floral disparity, we find that the most species-rich 'buzz-bee' pollination syndrome is most disparate, indicating that high floral disparity may evolve without pollinator shifts. Also, relatively species-poor clades and geographic areas contributed substantially to total disparity. Finally, our results show that machine-learning approaches are a powerful tool for evaluating the predictive accuracy of the pollination syndrome concept as well as for predicting pollinators where observations are missing.


Assuntos
Flores , Melastomataceae , Polinização , Polinização/fisiologia , Flores/fisiologia , Flores/anatomia & histologia , Melastomataceae/fisiologia , Abelhas/fisiologia , Animais , Filogenia , Especificidade da Espécie , Modelos Biológicos
18.
J Exp Biol ; 227(12)2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38773949

RESUMO

Bees use thoracic vibrations produced by their indirect flight muscles for powering wingbeats in flight, but also during mating, pollination, defence and nest building. Previous work on non-flight vibrations has mostly focused on acoustic (airborne vibrations) and spectral properties (frequency domain). However, mechanical properties such as the vibration's acceleration amplitude are important in some behaviours, e.g. during buzz pollination, where higher amplitude vibrations remove more pollen from flowers. Bee vibrations have been studied in only a handful of species and we know very little about how they vary among species. In this study, we conducted the largest survey to date of the biomechanical properties of non-flight bee buzzes. We focused on defence buzzes as they can be induced experimentally and provide a common currency to compare among taxa. We analysed 15,000 buzzes produced by 306 individuals in 65 species and six families from Mexico, Scotland and Australia. We found a strong association between body size and the acceleration amplitude of bee buzzes. Comparison of genera that buzz-pollinate and those that do not suggests that buzz-pollinating bees produce vibrations with higher acceleration amplitude. We found no relationship between bee size and the fundamental frequency of defence buzzes. Although our results suggest that body size is a major determinant of the amplitude of non-flight vibrations, we also observed considerable variation in vibration properties among bees of equivalent size and even within individuals. Both morphology and behaviour thus affect the biomechanical properties of non-flight buzzes.


Assuntos
Vibração , Animais , Abelhas/fisiologia , Fenômenos Biomecânicos , Tamanho Corporal , Polinização/fisiologia , México , Austrália , Escócia , Comunicação Animal
19.
Ann Bot ; 134(2): 311-324, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38712800

RESUMO

BACKGROUND AND AIMS: The deceptive strategies by which orchids are pollinated and how these are capable of attracting pollinators remain understudied with regard to their implications for plant fitness. Despite their ecological importance, limited investigations have been conducted on sexual deception and shelter mimicry in orchid species, making this a compelling avenue in orchid biology research. To expand the knowledge of these reproductive mechanisms, we studied the pollination of Serapias lingua and S. parviflora in co-occurring and isolated sites in the Balearic Islands (Spain), further accentuated by the presence of a hybrid, indicating shared pollinators. METHODS: We employed bagging and hand pollination experiments to examine the reproductive biology of the two species. Furthermore, we evaluated the influence of phenotypical and ecological factors on reproductive success, including biometric measurements, reproductive performance and neighbourhood diversity (co-flowering and pollinator communities). KEY RESULTS: Reproductive mechanisms between these two orchid species exhibit substantial disparities. Serapias lingua relies primarily on insect-mediated pollination, while S. parviflora demonstrates self-reproduction capacity. Although events of open pollination are rare, hybridization occurs predominantly when S. lingua is the pollen donor. Fruit set in S. parviflora was positively correlated with plant height, while in S. lingua it was negatively associated with flower size. The coexistence of the two species positively affected pollinium removal in S. parviflora, but did not exert an influence on reproductive traits in S. lingua. Overall, biometric parameters were diminished in isolated compared with co-occurring sites. At the community level, the increased diversity of co-flowering species in the vicinity exhibited an inhibitory effect on pollinium removal in S. parviflora. CONCLUSIONS: Under a context of pollinator loss or phenological mismatch between pollinator presence and flowering, the selfing capacity of S. parviflora would guarantee reproduction whereas S. lingua survival would be compromised. Furthers studies are needed to assess the effects of phenotypical and ecological factors on reproductive success of S. lingua in pollinator-decline scenarios.


Assuntos
Flores , Orchidaceae , Polinização , Reprodução , Polinização/fisiologia , Orchidaceae/fisiologia , Reprodução/fisiologia , Animais , Flores/fisiologia , Espanha , Insetos/fisiologia , Frutas/fisiologia , Ecossistema , Especificidade da Espécie , Pólen/fisiologia
20.
Ann Bot ; 134(2): 325-336, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38720433

RESUMO

BACKGROUND AND AIMS: There are intrinsic conflicts between signalling to mutualists and concealing (camouflaging) from antagonists. Like animals, plants also use camouflage as a defence against herbivores. However, this can potentially reduce their attractiveness to pollinators. METHODS: Using Fritillaria delavayi, an alpine camouflaged plant with inter-population floral colour divergence, we tested the influence of floral trait differences on reproduction. We conducted pollination experiments, measured floral morphological characteristics, estimated floral colours perceived by pollinators, analysed floral scent and investigated reproductive success in five populations. KEY RESULTS: We found that the reproduction of F. delavayi depends on pollinators. Under natural conditions, a flower-camouflaged population had 100 % fruit set and similar seed set to three out of four yellow-flowered populations. Bumblebees are important pollinators in the visually conspicuous yellow-flowered populations, whereas flies are the only pollinator in the flower-camouflaged population, visiting flowers more frequently than bumblebees. The camouflaged flowers cannot be discriminated from the rock background as perceived by pollinators, but may be located by flies through olfactory cues. CONCLUSIONS: Collectively, our results demonstrate that the flower-camouflaged population has different reproductive traits from the visually conspicuous yellow-flowered populations. A pollinator shift from bumblebees to flies, combined with high visitation frequency, compensates for the attractiveness disadvantage in camouflaged plants.


Assuntos
Flores , Fritillaria , Polinização , Reprodução , Polinização/fisiologia , Animais , Flores/fisiologia , Flores/anatomia & histologia , Reprodução/fisiologia , Abelhas/fisiologia , Fritillaria/fisiologia , Dípteros/fisiologia , Cor , Frutas/fisiologia , Mimetismo Biológico/fisiologia , Pigmentação/fisiologia
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