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1.
Nat Commun ; 12(1): 1937, 2021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33782399

RESUMO

137Cs is a long-lived (30-year radioactive half-life) fission product dispersed globally by mid-20th century atmospheric nuclear weapons testing. Here we show that vegetation thousands of kilometers from testing sites continues to cycle 137Cs because it mimics potassium, and consequently, bees magnify this radionuclide in honey. There were no atmospheric weapons tests in the eastern United States, but most honey here has detectable 137Cs at >0.03 Bq kg-1, and in the southeastern U.S., activities can be >500 times higher. By measuring honey, we show regional patterns in the biogeochemical cycling of 137Cs and conclude that plants and animals receive disproportionally high exposure to ionizing radiation from 137Cs in low potassium soils. In several cases, the presence of 137Cs more than doubled the ionizing radiation from gamma and x-rays in the honey, indicating that despite its radioactive half-life, the environmental legacy of regional 137Cs pollution can persist for more than six decades.


Assuntos
Radioisótopos de Césio/metabolismo , Mel/análise , Plantas/metabolismo , Poluentes Radioativos do Solo/metabolismo , Solo/química , Animais , Abelhas/química , Abelhas/fisiologia , Radioisótopos de Césio/química , História do Século XX , História do Século XXI , Armas Nucleares/história , Plantas/química , Polinização/fisiologia , Poluentes Radioativos do Solo/química , Análise Espaço-Temporal , Estados Unidos
2.
Nat Commun ; 12(1): 718, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33531484

RESUMO

Ficus (figs) and their agaonid wasp pollinators present an ecologically important mutualism that also provides a rich comparative system for studying functional co-diversification throughout its coevolutionary history (~75 million years). We obtained entire nuclear, mitochondrial, and chloroplast genomes for 15 species representing all major clades of Ficus. Multiple analyses of these genomic data suggest that hybridization events have occurred throughout Ficus evolutionary history. Furthermore, cophylogenetic reconciliation analyses detect significant incongruence among all nuclear, chloroplast, and mitochondrial-based phylogenies, none of which correspond with any published phylogenies of the associated pollinator wasps. These findings are most consistent with frequent host-switching by the pollinators, leading to fig hybridization, even between distantly related clades. Here, we suggest that these pollinator host-switches and fig hybridization events are a dominant feature of fig/wasp coevolutionary history, and by generating novel genomic combinations in the figs have likely contributed to the remarkable diversity exhibited by this mutualism.


Assuntos
Ficus/fisiologia , Vespas/fisiologia , Animais , Evolução Biológica , Hibridização Genética , Filogenia , Polinização/fisiologia , Simbiose/fisiologia
3.
Planta ; 253(1): 19, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33394122

RESUMO

In flowering plants, pollen germination on the stigma and pollen tube growth in pistil tissues are critical for sexual plant reproduction, which are involved in the interactions between pollen/pollen tube and pistil tissues. GPI-anchored proteins (GPI-APs) are located on the external surface of the plasma membrane and function in various processes of sexual plant reproduction. The evidences suggest that GPI-APs participate in endosome machinery, Ca2+ oscillations, the development of the transmitting tract, the maintenance of the integrity of pollen tube, the enhancement of interactions of the receptor-like kinase (RLK) and ligand, and guidance of the growth of pollen tube, and so on. In this review, we will summarize the recent progress on the roles of GPI-APs in the interactions between pollen/pollen tube and pistil tissues during pollination, such as pollen germination on the stigma, pollen tube growth in the transmitting tract, pollen tube guidance to the ovule, and pollen tube reception in the embryo sac. We will also discuss the future outlook of GPI-APs in the interactions between pollen/pollen tube and pistil tissues.


Assuntos
Flores , Proteínas Ligadas por GPI , Proteínas de Plantas , Tubo Polínico , Flores/metabolismo , Proteínas Ligadas por GPI/metabolismo , Óvulo Vegetal/metabolismo , Proteínas de Plantas/metabolismo , Tubo Polínico/metabolismo , Polinização/fisiologia , Pesquisa/tendências
4.
PLoS One ; 15(12): e0237484, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33332351

RESUMO

Livestock grazing and non-native plant species affect rangeland habitats globally. These factors may have important effects on ecosystem services including pollination, yet, interactions between pollinators, grazing, and invasive plants are poorly understood. To address this, we tested the hypothesis that cattle grazing and site colonization by cheatgrass (Bromus tectorum) impact bee foraging and nesting habitats, and the biodiversity of wild bee communities, in a shortgrass prairie system. Bee nesting habitats (litter and wood cover) were marginally improved in non-grazed sites with low cheatgrass cover, though foraging habitat (floral cover and richness, bare soil) did not differ among cattle-grazed sites or non-grazed sites with low or high cheatgrass cover. However, floral cover was a good predictor of bee abundance and functional dispersion. Mean bee abundance, richness, diversity and functional diversity were significantly lower in cattle-grazed habitats than in non-grazed habitats. Differences in bee diversity among habitats were pronounced early in the growing season (May) but by late-season (August) these differences eroded as Melissodes spp. and Bombus spp. became more abundant at study sites. Fourth-corner analysis revealed that sites with high floral cover tended to support large, social, polylectic bees; sites with high grass cover tended to support oligolectic solitary bees. Both cattle-grazed sites and sites with high cheatgrass cover were associated with lower abundances of above-ground nesting bees but higher abundance of below-ground nesters than non-grazed sites with low cheatgrass cover. We conclude that high cheatgrass cover is not associated with reduced bee biodiversity or abundance, but cattle grazing was negatively associated with bee abundances and altered species composition. Although floral cover is an important predictor of bee assemblages, this was not impacted by cattle grazing and our study suggests that cattle likely impact bee communities through effects other than those mediated by forbs, including soil disturbance or nest destruction. Efforts aimed at pollinator conservation in prairie habitats should focus on managing cattle impacts early in the growing season to benefit sensitive bee species.


Assuntos
Abelhas/fisiologia , Gado/fisiologia , Polinização/fisiologia , Animais , Biodiversidade , Bromus/fisiologia , Bovinos , Ecossistema , Flores/fisiologia , Pradaria , Plantas , Estações do Ano
5.
Proc Natl Acad Sci U S A ; 117(34): 20653-20661, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32778582

RESUMO

While the impact of air pollution on human health is well studied, mechanistic impacts of air pollution on wild systems, including those providing essential ecosystem services, are largely unknown, but directly impact our health and well-being. India is the world's largest fruit producer, second most populous country, and contains 9 of the world's 10 most polluted cities. Here, we sampled Giant Asian honey bees, Apis dorsata, at locations with varying air pollution levels in Bangalore, India. We observed significant correlations between increased respirable suspended particulate matter (RSPM) deposition and changes in bee survival, flower visitation, heart rate, hemocyte levels, and expression of genes related to lipid metabolism, stress, and immunity. Lab-reared Drosophila melanogaster exposed to these same sites also exhibited similar molecular and physiological differences. Our study offers a quantitative analysis on the current impacts of air pollution on insects, and indicates the urgency for more nonhuman studies to accurately assess the effects of pollution on our natural world.


Assuntos
Poluição do Ar/efeitos adversos , Abelhas/fisiologia , Polinização/fisiologia , Animais , Abelhas/efeitos dos fármacos , Cidades , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/fisiologia , Ecossistema , Estudos de Avaliação como Assunto , Humanos , Índia , Insetos/fisiologia , Material Particulado/efeitos adversos
6.
Nat Commun ; 11(1): 4086, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32796828

RESUMO

Ecological communities often show changes in populations and their interactions over time. To date, however, it has been challenging to effectively untangle the mechanisms shaping such dynamics. One approach that has yet to be fully explored is to treat the varying structure of empirical communities-i.e. their network of interactions-as time series. Here, we follow this approach by applying a network-comparison technique to study the seasonal dynamics of plant-pollinator networks. We find that the structure of these networks is extremely variable, where species constantly change how they interact with each other within seasons. Most importantly, we find the holistic dynamic of plants and pollinators to be remarkably coherent across years, allowing us to reveal general rules by which species first enter, then change their roles, and finally leave the networks. Overall, our results disentangle key aspects of species' interaction turnover, phenology, and seasonal assembly/disassembly processes in empirical plant-pollinator communities.


Assuntos
Polinização/fisiologia , Animais , Biodiversidade , Biota , Insetos/fisiologia , Estações do Ano
7.
PLoS One ; 15(7): e0216190, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32639984

RESUMO

Understanding how bees use resources at a landscape scale is essential for developing meaningful management plans that sustain populations and the pollination services they provide. Bumblebees are important pollinators for many wild and cultivated plants, and have experienced steep population declines worldwide. Bee foraging behavior can be influenced by resource availability and bees' lifecycle stage. To better understand these relationships, we studied the habitat selection of Bombus pauloensis by tracking 17 queen bumblebees with radio telemetry in blueberry fields in Entre Ríos province, Argentina. To evaluate land use and floral resources used by bumblebees, we tracked bees before and after nest establishment and estimated home ranges using minimum convex polygons and kernel density methods. We also classified the pollen on their bodies to identify the floral resources they used from the floral species available at that time. We characterized land use for each bee as the relative proportion of GPS points inside of each land use. Bumblebees differed markedly in their movement behavior in relation to pre and post nest establishment. Bees moved over larger areas, and mostly within blueberry fields, before nest establishment. In contrast, after establishing the nest, the bees preferred the edges near forest plantations and they changed the nutritional resources to prefer wild floral species. Our study is the first to track queen bumblebee movements in an agricultural setting and relate movement changes across time and space with pollen resource availability. This study provides insight into the way bumblebee queens use different habitat elements at crucial periods in their lifecycle, showing the importance of mass flowering crops like blueberry in the first stages of queen's lifecycle, and how diversified landscapes help support bee populations as their needs changes during different phases of their lifecycle.


Assuntos
Agricultura , Abelhas/fisiologia , Polinização/fisiologia , Animais , Mirtilos Azuis (Planta) , Comportamento de Retorno ao Território Vital , Densidade Demográfica , Análise Espaço-Temporal
8.
PLoS One ; 15(6): e0234498, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584843

RESUMO

Bumble bee communities are strongly disrupted worldwide through the population decline of many species; a phenomenon that has been generally attributed to landscape modification, pesticide use, pathogens, and climate change. The mechanisms by which these causes act on bumble bee colonies are, however, likely to be complex and to involve many levels of organization spanning from the community down to the least understood individual level. Here, we assessed how the morphology, weight and foraging behavior of individual workers are affected by their surrounding landscape. We hypothesized that colonies established in landscapes showing high cover of intensive crops and low cover of flowering crops, as well as low amounts of local floral resources, would produce smaller workers, which would perform fewer foraging trips and collect pollen loads less constant in species composition. We tested these predictions with 80 colonies of commercially reared Bombus impatiens Cresson placed in 20 landscapes spanning a gradient of agricultural intensification in southern Québec, Canada. We estimated weekly rate at which workers entered and exited colonies and captured eight workers per colony over a period of 14 weeks during the spring and summer of 2016. Captured workers had their wing, thorax, head, tibia, and dry weight measured, as well as their pollen load extracted and identified to the lowest possible taxonomic level. We did not detect any effect of landscape habitat composition on worker morphology or body weight, but found that foraging activity decreased with intensive crops. Moreover, higher diversity of local floral resources led to lower pollen constancy in intensively cultivated landscapes. Finally, we found a negative correlation between the size of workers and the diversity of their pollen load. Our results provide additional evidence that conservation actions regarding pollinators in arable landscapes should be made at the landscape rather than at the farm level.


Assuntos
Abelhas/fisiologia , Ecossistema , Pólen/fisiologia , Polinização/fisiologia , Animais , Canadá , Produtos Agrícolas , Humanos , Quebeque , Estações do Ano
9.
Sci Rep ; 10(1): 9476, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32528048

RESUMO

Intraspecific floral colour polymorphism is a common trait of food deceptive orchids, which lure pollinators with variable, attractive signals, without providing food resources. The variable signals are thought to hinder avoidance learning of deceptive flowers by pollinators. Here, we analysed the cognitive mechanisms underlying the choice of free-flying stingless bees Scaptotrigona aff. depilis trained to visit a patch of artificial flowers that displayed the colours of Ionopsis utricularioides, a food deceptive orchid. Bees were trained in the presence of a non-rewarding colour and later tested with that colour vs. alternative colours. We simulated a discrete-polymorphism scenario with two distinct non-rewarding test colours, and a continuous-polymorphism scenario with three non-rewarding test colours aligned along a chromatic continuum. Bees learned to avoid the non-rewarding colour experienced during training. They thus preferred the novel non-rewarding colour in the discrete-polymorphic situation, and generalized their avoidance to the adjacent colour of the continuum in the continuous-polymorphism situation, favouring thereby the most distant colour. Bees also visited less flowers and abandoned faster a non-rewarding monomorphic patch than a non-rewarding polymorphic patch. Our cognitive analyses thus reveal that variable deceptive orchids disrupt avoidance learning by pollinators and exploit their generalization abilities, which make them favour distinct morphs.


Assuntos
Abelhas/fisiologia , Cognição/fisiologia , Comportamento Alimentar/fisiologia , Polinização/fisiologia , Animais , Aprendizagem da Esquiva/fisiologia , Cor , Flores/fisiologia , Orchidaceae/fisiologia , Pólen/fisiologia
10.
Emerg Top Life Sci ; 4(1): 33-43, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32537636

RESUMO

Plant induced responses to herbivory have long been found to function as plant direct and indirect defenses and to be major drivers of herbivore community and population dynamics. While induced defenses are generally understood as cost-saving strategies that allow plants to allocate valuable resources into defense expression, it recently became clear that, in particular, induced metabolic changes can come with significant ecological costs. In particular, interactions with mutualist pollinators can be significantly compromised by herbivore-induced changes in floral morphology and metabolism. We review recent findings on the evidence for ecological conflict between defending against herbivores and attracting pollinators while using similar modes of information transfer (e.g. visual, olfactory, tactile). Specifically, we discuss plant traits and mechanisms through which plants mediate interactions between antagonists and mutualist and present functional hypotheses for how plants can overcome the resulting conflicts.


Assuntos
Flores/metabolismo , Herbivoria/fisiologia , Plantas/metabolismo , Polinização/fisiologia , Ecologia , Interações Hospedeiro-Parasita , Fenótipo , Fenômenos Fisiológicos Vegetais , Metabolismo Secundário , Simbiose
11.
Emerg Top Life Sci ; 4(1): 87-97, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32558902

RESUMO

Ecosystems are at increasing risk from the global pollination crisis. Gaining better knowledge about pollinators and their interactions with plants is an urgent need. However, conventional methods of manually recording pollinator activity in the field can be time- and cost-consuming in terms of labour. Field-deployable video recording systems have become more common in ecological studies as they enable the capture of plant-insect interactions in fine detail. Standard video recording can be effective, although there are issues with hardware reliability under field-conditions (e.g. weatherproofing), and reviewing raw video manually is a time-consuming task. Automated video monitoring systems based on motion detection partly overcome these issues by only recording when activity occurs hence reducing the time needed to review footage during post-processing. Another advantage of these systems is that the hardware has relatively low power requirements. A few systems have been tested in the field which permit the collection of large datasets. Compared with other systems, automated monitoring allows vast increases in sampling at broad spatiotemporal scales. Some tools such as post-recording computer vision software and data-import scripts exist, further reducing users' time spent processing and analysing the data. Integrated computer vision and automated species recognition using machine learning models have great potential to further the study of pollinators in the field. Together, it is predicted that future advances in technology-based field monitoring methods will contribute significantly to understanding the causes underpinning pollinator declines and, hence, developing effective solutions for dealing with this global challenge.


Assuntos
Insetos/fisiologia , Plantas/parasitologia , Polinização/fisiologia , Gravação em Vídeo/instrumentação , Animais , Ecossistema , Processamento Eletrônico de Dados , Monitoramento Ambiental , Interações Hospedeiro-Parasita
12.
Emerg Top Life Sci ; 4(1): 7-17, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32558903

RESUMO

The bee-flower biological association is one of the most famous examples of insect-plant interactions, and it is axiomatic that these are of critical importance for sustaining thriving terrestrial ecosystems. Yet, the most familiar associations are often artificially managed agricultural ecosystems, reflecting an exceptionally narrow range of bee species (often only one) and a concomitantly restricted range of associated behaviors, morphologies, and mechanisms tied to pollination. Here we provide a brief account of the range of bee-floral associations encompassing floral specialization in terms of diet, behavior, and morphology. These natural associations not only promote healthy ecosystems, but also can be integrated in sustainable ways for more efficient pollination of crops by targeting bee species whose diets, behaviors, and pollen-gathering structures evolved precisely to visit such floral species rather than less efficient, and often non-native, generalists that are otherwise exploited for such purposes.


Assuntos
Abelhas/fisiologia , Produtos Agrícolas , Flores , Pólen , Polinização/fisiologia , Animais , Biodiversidade , Evolução Biológica , Dieta , Ecossistema , Interações Hospedeiro-Parasita , Comportamento de Busca por Hospedeiro
13.
Emerg Top Life Sci ; 4(1): 77-86, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32558904

RESUMO

The mutualism between plants and their pollinators provides globally important ecosystem services, but it is likely to be disrupted by global warming that can cause mismatches between both halves of this interaction. In this review, we summarise the available evidence on (i) spatial or (ii) phenological shifts of one or both of the actors of this mutualism. While the occurrence of future spatial mismatches is predominantly theoretical and based on predictive models, there is growing empirical evidence of phenological mismatches occurring at the present day. Mismatches may also occur when pollinators and their host plants are still found together. These mismatches can arise due to (iii) morphological modifications and (iv) disruptions to host attraction and foraging behaviours, and it is expected that these mismatches will lead to novel community assemblages. Overall plant-pollinator interactions seem to be resilient biological networks, particularly because generalist species can buffer these changes due to their plastic behaviour. However, we currently lack information on where and why spatial mismatches do occur and how they impact the fitness of plants and pollinators, in order to fully assess if adaptive evolutionary changes can keep pace with global warming predictions.


Assuntos
Aquecimento Global , Insetos/fisiologia , Plantas/parasitologia , Polinização/fisiologia , Animais , Evolução Biológica , Dieta , Ecossistema , Efeito Estufa , Interações Hospedeiro-Parasita , Desenvolvimento Vegetal , Simbiose , Temperatura
14.
Emerg Top Life Sci ; 4(1): 19-32, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32478390

RESUMO

Existing assessments of the ecosystem service of pollination have been largely restricted to diurnal insects, with a particular focus on generalist foragers such as wild and honey bees. As knowledge of how these plant-pollinator systems function, their relevance to food security and biodiversity, and the fragility of these mutually beneficial interactions increases, attention is diverting to other, less well-studied pollinator groups. One such group are those that forage at night. In this review, we document evidence that nocturnal species are providers of pollination services (including pollination of economically valuable and culturally important crops, as well as wild plants of conservation concern), but highlight how little is known about the scale of such services. We discuss the primary mechanisms involved in night-time communication between plants and insect pollen-vectors, including floral scent, visual cues (and associated specialized visual systems), and thermogenic sensitivity (associated with thermogenic flowers). We highlight that these mechanisms are vulnerable to direct and indirect disruption by a range of anthropogenic drivers of environmental change, including air and soil pollution, artificial light at night, and climate change. Lastly, we highlight a number of directions for future research that will be important if nocturnal pollination services are to be fully understood and ultimately conserved.


Assuntos
Flores , Insetos/fisiologia , Pólen , Polinização/fisiologia , Animais , Biodiversidade , Mudança Climática , Produtos Agrícolas , Ecossistema , Poluição Ambiental , Interações Hospedeiro-Parasita , Luz , Estações do Ano , Transdução de Sinais , Fatores de Tempo
15.
Nat Commun ; 11(1): 2395, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32409656

RESUMO

Pollen tubes are highly polarized tip-growing cells that depend on cytosolic pH gradients for signaling and growth. Autoinhibited plasma membrane proton (H+) ATPases (AHAs) have been proposed to energize pollen tube growth and underlie cell polarity, however, mechanistic evidence for this is lacking. Here we report that the combined loss of AHA6, AHA8, and AHA9 in Arabidopsis thaliana delays pollen germination and causes pollen tube growth defects, leading to drastically reduced fertility. Pollen tubes of aha mutants had reduced extracellular proton (H+) and anion fluxes, reduced cytosolic pH, reduced tip-to-shank proton gradients, and defects in actin organization. Furthermore, mutant pollen tubes had less negative membrane potentials, substantiating a mechanistic role for AHAs in pollen tube growth through plasma membrane hyperpolarization. Our findings define AHAs as energy transducers that sustain the ionic circuit defining the spatial and temporal profiles of cytosolic pH, thereby controlling downstream pH-dependent mechanisms essential for pollen tube elongation, and thus plant fertility.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Tubo Polínico/crescimento & desenvolvimento , Polinização/fisiologia , ATPases Translocadoras de Prótons/metabolismo , Proteínas de Arabidopsis/genética , Membrana Celular/metabolismo , Polaridade Celular/fisiologia , Citosol/metabolismo , Técnicas de Silenciamento de Genes , Germinação/fisiologia , Concentração de Íons de Hidrogênio , Potenciais da Membrana/fisiologia , Mutação , Plantas Geneticamente Modificadas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ATPases Translocadoras de Prótons/genética , Análise Espaço-Temporal
16.
Proc Natl Acad Sci U S A ; 117(21): 11559-11565, 2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32393622

RESUMO

Pathogens pose significant threats to pollinator health and food security. Pollinators can transmit diseases during foraging, but the consequences of plant species composition for infection is unknown. In agroecosystems, flowering strips or hedgerows are often used to augment pollinator habitat. We used canola as a focal crop in tents and manipulated flowering strip composition using plant species we had previously shown to result in higher or lower bee infection in short-term trials. We also manipulated initial colony infection to assess impacts on foraging behavior. Flowering strips using high-infection plant species nearly doubled bumble bee colony infection intensity compared to low-infection plant species, with intermediate infection in canola-only tents. Both infection treatment and flowering strips reduced visits to canola, but we saw no evidence that infection treatment shifted foraging preferences. Although high-infection flowering strips increased colony infection intensity, colony reproduction was improved with any flowering strips compared to canola alone. Effects of flowering strips on colony reproduction were explained by nectar availability, but effects of flowering strips on infection intensity were not. Thus, flowering strips benefited colony reproduction by adding floral resources, but certain plant species also come with a risk of increased pathogen infection intensity.


Assuntos
Abelhas , Brassica napus , Flores , Infecções Protozoárias em Animais , Animais , Comportamento Apetitivo/fisiologia , Abelhas/parasitologia , Abelhas/fisiologia , Brassica napus/microbiologia , Brassica napus/parasitologia , Crithidia/patogenicidade , Ecossistema , Flores/parasitologia , Flores/fisiologia , Larva/fisiologia , Polinização/fisiologia , Infecções Protozoárias em Animais/fisiopatologia , Infecções Protozoárias em Animais/transmissão
17.
An Acad Bras Cienc ; 92 Suppl 1: e20180558, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348411

RESUMO

The study investigated native solitary bee species that nest in pre-existing cavities in the Baturité Massif, State of Ceará, Brazil, their preference for nest substrates and aspects of these bee communities. Samples were taken in four distinct areas of the Baturité Massif using three types of trap-nests: dried bamboo internodes, cardboard tubes and rational boxes. Out of the 185 nests offered, 34 were colonized and 24 of them produced 131 bees, belonging to two families (Apidae and Megachilidae) and five genera (Centris, Mesocheira, Euglossa, Megachile and Coelioxys) from six species, including parasitic ones. Nesting preference was observed to certain types of substrates (χ²=17.89, p<0.001), with bamboo internodes being preferred by bee to build their nests, while monthly variation in temperature and humidity did not affect bee emergency. Spite of few nests foundations and the few species sampled, this work contributed to an unprecedented knowledge about the species that use pre-existing cavities in the Baturité Massif that may contribute to assist in the maintenance and conservation of this mountainous area and can be useful for pollination services of native and agricultural plants.


Assuntos
Abelhas/fisiologia , Comportamento de Nidação/fisiologia , Animais , Brasil , Florestas , Polinização/fisiologia , Estações do Ano
18.
BMC Plant Biol ; 20(1): 137, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32245411

RESUMO

BACKGROUND: Flower longevity plays an important role in pollen dispersal and reproductive success in plants. In dichogamous plants, the duration of anthesis as well as the time allocated to male and female functions can vary in response to intrinsic factors (e.g., flowering time and resource allocation) and pollination context along a growth season. However, the fitness consequences of phenological dynamics have rarely been examined. This study aims to unravel the potential causes driving variation in flower longevity, duration of sex phases, and phenotypic sex during a flowering season of strongly protandrous Aconitum gymnandrum, and particularly reproductive consequences of the phenological pattern. RESULTS: Population floral sex ratio shifted from completely male at the beginning to completely female at the end of the season, as is common in other protandrous plants. Phenological dynamics of the floral sex ratio and the duration of sex phases caused a shift from femaleness to maleness in the mean phenotypic sex over the whole season. Floral longevity was negatively correlated with flower size and positively affected by temperature. Early flowers within inflorescences rather than early-flowering individuals emphasized the duration of female over male phase. Owing to the dominance of male-phase flowers, early flowering for individual flowers and plants, or female-biased sex resulted in higher pollen deposition per flower and seed set. At the flower level, flower longevity positively affected female reproductive success, while the effect of flower size was negative. By contrast, plant-level female reproductive success was negatively affected by flower longevity but positively correlated to flower size. CONCLUSIONS: The major result of this study lies in elucidating the relationship between variation in phenological sex expression and floral longevity and their fitness consequences of protandrous A. gymnandrum. The contrasting results on female fitness for individual flowers and plants contribute to our current understanding of the adaptive significance of floral longevity.


Assuntos
Aconitum/fisiologia , Flores , Longevidade , Adaptação Fisiológica , Flores/crescimento & desenvolvimento , Flores/fisiologia , Organismos Hermafroditas/fisiologia , Polinização/fisiologia , Reprodução/fisiologia , Estações do Ano , Razão de Masculinidade , Tundra
19.
Sci Rep ; 10(1): 6143, 2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-32273546

RESUMO

Pollen dispersal is one of the main ways of gene flow. In the past years, rice pollen dispersal and gene flow have been well studies. However, there is much dispute whether the risk of pollen dispersal and gene flow continuously increases with the source area. A Lagrangian stochastic model was used to simulate the pollen depositions at different distances from different pollen source areas. The field experiments showed a good fit in the pollen depositions. The larger the source area, the more the pollen grains were deposited at each distance, with the pollen dispersal distance increasing accordingly. However, this effect gradually leveled off as the source area increased. In the large-area of pollen source, we found a significantly higher saturation point for the amount of pollen deposition. Once the source area exceeded 1000 × 1000 m2, the pollen deposition no longer increased, even if the source area continued to increase, indicating the "critical source area" of rice pollen dispersal. However, a 100 × 100 m2 critical source area for conventional rice and hybrid rice was sufficient, while the critical source area for the sterile line was about 230 × 230 m2.


Assuntos
Fluxo Gênico , Oryza/fisiologia , Polinização , Fluxo Gênico/fisiologia , Modelos Estatísticos , Oryza/genética , Pólen , Polinização/fisiologia
20.
Plant Mol Biol ; 103(1-2): 9-32, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32124177

RESUMO

KEY MESSAGE: In light of the available discoveries in the field, this review manuscript discusses on plant reproduction mechanism and molecular players involved in the process. Sperm cells in angiosperms are immotile and are physically distant to the female gametophytes (FG). To secure the production of the next generation, plants have devised a clever approach by which the two sperm cells in each pollen are safely delivered to the female gametophyte where two fertilization events occur (by each sperm cell fertilizing an egg cell and central cell) to give rise to embryo and endosperm. Each of the successfully fertilized ovules later develops into a seed. Sets of macromolecules play roles in pollen tube (PT) guidance, from the stigma, through the transmitting tract and funiculus to the micropylar end of the ovule. Other sets of genetic players are involved in PT reception and in its rupture after it enters the ovule, and yet other sets of genes function in gametic fusion. Angiosperms have come long way from primitive reproductive structure development to today's sophisticated, diverse, and in most cases flamboyant organ. In this review, we will be discussing on the intricate yet complex molecular mechanism of double fertilization and how it might have been shaped by the evolutionary forces focusing particularly on the model plant Arabidopsis.


Assuntos
Flores/fisiologia , Magnoliopsida/fisiologia , Polinização/fisiologia , Evolução Biológica , Gametogênese Vegetal , Óvulo Vegetal/fisiologia , Pólen/fisiologia , Sementes
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