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1.
Mol Ecol ; 33(6): e17285, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38288563

RESUMO

Understanding how spatial patterns of mating and gene flow respond to habitat loss and geographical isolation is a crucial aspect of forest fragmentation genetics. Naturally fragmented riparian tree populations exhibit unique characteristics that significantly influence these patterns. In this study, we investigate mating patterns, pollen-mediated gene flow, and genetic diversity in relict populations of Frangula alnus in southern Spain by testing specific hypotheses related to the riparian habitat. We employ a novel approach that combines paternity analysis, particularly suited for small and isolated populations, with complex network theory and Bayesian models to predict mating likelihood among tree pairs. Our findings reveal a prevalence of short-distance pollination, resulting in spatially driven local mating clusters with a distinct subset of trees being highly connected in the mating network. Additionally, we observe numerous pollination events over distances of hundreds of metres and considerable pollen immigration. Local neighbourhood density is the primary factor influencing within-population mating patterns and pollen dispersal; moreover, mating network properties reflect the population's size and spatial configuration. Conversely, among-population pollen dispersal is mainly determined by tree size, which influences floral display. Our results do not support a major role of directional pollen dispersal in longitudinal trends of genetic diversity. We provide evidence that long-term fragmented tree populations persist in unique environments that shape mating patterns and impose constraints to pollen-mediated gene flow. Nevertheless, even seemingly strongly isolated populations can maintain functional connectivity over extended periods, especially when animal-mediated mating networks promote genetic diversity, as in this riparian tree species.


Assuntos
Genética Populacional , Repetições de Microssatélites , Animais , Teorema de Bayes , Repetições de Microssatélites/genética , Reprodução/genética , Polinização/genética , Fluxo Gênico , Variação Genética/genética
2.
Am J Bot ; 111(3): e16303, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38531667

RESUMO

PREMISE: Vertical stratification is a key feature of tropical forests and plant-frugivore interactions. However, it is unclear whether equally strong patterns of vertical stratification exist for plant-nectarivore interactions and, if so, which factors drive these patterns. Further, nectar-inhabiting bacteria, acting as "hidden players" in plant-nectarivore interactions, might be vertically stratified, either in response to differences among strata in microenvironmental conditions or to the nectarivore community serving as vectors. METHODS: We observed visitations by a diverse nectarivore community to the liana Marcgravia longifolia in a Peruvian rainforest and characterized diversity and community composition of nectar-inhabiting bacteria. Unlike most other plants, M. longifolia produces inflorescences across forest strata, enabling us to study effects of vertical stratification on plant-nectarivore interactions without confounding effects of plant species and stratum. RESULTS: A significantly higher number of visits were by nectarivorous bats and hummingbirds in the midstory than in the understory and canopy, and the visits were strongly correlated to flower availability and nectar quantity and quality. Trochiline hummingbirds foraged across all strata, whereas hermits remained in the lower strata. The Shannon diversity index for nectar-inhabiting bacterial communities was highest in the midstory. CONCLUSIONS: Our findings suggest that vertical niche differentiation in plant-nectarivore interactions seems to be partly driven by resource abundance, but other factors such as species-specific preferences of hummingbirds, likely caused by competition, play an important role. We conclude that vertical stratification is an important driver of a species' interaction niche highlighting its role for promoting biodiversity and ecosystem functioning.


Assuntos
Ecossistema , Néctar de Plantas , Animais , Florestas , Biodiversidade , Flores , Aves/fisiologia
3.
J Plant Res ; 137(4): 605-617, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38506958

RESUMO

The intervention of nectar robbers in plant pollination systems will cause some pollinators to modify their foraging behavior to act as secondary robbers, consequently adopting a mixed foraging strategy. The influence of nectar robbing on pollinator behavior may be affected by spatio-temporal difference of robbing intensity, and consequently, may have different effects on the pollination of host plants. However, whether and how the nectar robbing might influence pollinators under different robbing intensity still needs further investigation. In this study, Symphytum officinale was used to detect the effect of nectar robbers on pollinators under different robbing intensity as well as their effects on plant reproductive success. Six robbing levels and three bumblebees with mixed foraging behaviors were used to evaluate the effect of different robbing intensity on pollinator behavior, visitation rate, flower longevity and pollen deposition. Our results indicated that the robbing rate increased gradually with the proportion of robbed flowers, but which did not affect the frequency of legitimate visits. The increase of robbing rate promoted the corolla abscission, and then enhanced the self-pollen deposition, but which had no significant effect on cross-pollen deposition. These results indicate that the overall fitness of S. officinale was improved by combined self and cross-pollination modes when visited by both pollinators and nectar robbers simultaneously. Although nectar robbing is not uncommon, its consequences for pollination in the interaction web have not been well studied. Our results emphasize the significance of indirect impacts in mediating the adaptive outcomes of species interactions.


Assuntos
Boraginaceae , Flores , Néctar de Plantas , Polinização , Reprodução , Polinização/fisiologia , Flores/fisiologia , Animais , Abelhas/fisiologia , Reprodução/fisiologia , Néctar de Plantas/fisiologia , Boraginaceae/fisiologia , Pólen/fisiologia
4.
Plants (Basel) ; 13(4)2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38498564

RESUMO

Florivores consume floral structures with negative effects on plant fitness and pollinator attraction. Several studies have evaluated these consequences in hermaphroditic plants, but little is known about the effects on monoecious and dioecious species. We characterize the florivory and its effects on floral visitors and reproductive success in a monoecious population of Sagittaria lancifolia. Five categories of florivory were established according to the petal area consumed. Visits were recorded in male and female flowers within the different damage categories. Reproductive success was evaluated through fruit number and weight, as well as the number of seeds per fruit. Our results show that the weevil Tanysphyrus lemnae is the main florivore, and it mainly damages the female flowers. Hymenoptera were recorded as the most frequent visitors of both male and female flowers. Male and female flowers showed differences in visit frequency, which decreases as flower damage increases. Reproductive success was negatively related to the level of damage. We found that florivory is common in the population of S. lancifolia, which can exert a strong selective pressure by making the flowers less attractive and reducing the number of seeds per fruit. Future studies are needed to know how florivores affect plant male fitness.

5.
BMC Ecol Evol ; 24(1): 10, 2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38243160

RESUMO

BACKGROUND: Artificial light at night, also referred to as light pollution (LP), has been shown to affect many organisms. However, little is known about the extent to which ecological interactions between earthworms and plants are altered by LP. We investigated the effects of LP on anecic earthworms (Lumbricus terrestris) that come to the surface at night to forage and mate, and on the germination and growth of the invasive and allergenic ragweed (Ambrosia artemisiifolia). In a full factorial pot experiment in the greenhouse, we tested four factors and their interactions: LP (5 lux vs. 0 lux at night), earthworms (two individuals vs. none), plant species (seeding of ragweed only vs. mixed with Phacelia seeds) and sowing depth (seed placed at the surface vs. in 5 cm depth). Data were analysed using Generalized Linear (Mixed) Models and multifactorial ANOVAs with soil parameters as covariates. RESULTS: Light pollution reduced earthworm surface activity by 76% as measured by casting activity and toothpick index; 85% of mating earthworms were observed in the absence of LP. Light pollution in interaction with earthworms reduced ragweed germination by 33%. However, LP increased ragweed height growth by 104%. Earthworms reduced ragweed germination especially when seeds were placed on the soil surface, suggesting seed consumption by earthworms. CONCLUSIONS: Our data suggest that anecic earthworms are negatively affected by LP because reduced surface activity limits their ability to forage and mate. The extent to which earthworm-induced ecosystem services or community interactions are also affected by LP remains to be investigated. If the increased height growth of ragweed leads to increased pollen and seed production, it is likely that the competition of ragweed with field crops and the risks to human health will also increase under LP.


Assuntos
Oligoquetos , Animais , Humanos , Ecossistema , Ambrosia , Poluição Luminosa , Solo
6.
Ecology ; 105(5): e4306, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38590050

RESUMO

Plants produce an array of defensive compounds with toxic or deterrent effects on insect herbivores. Pollen can contain relatively high concentrations of such defense compounds, but the causes and consequences of this enigmatic phenomenon remain mostly unknown. These compounds could potentially protect pollen against antagonists but could also reduce flower attractiveness to pollinators. We combined field observations of the pollen-rewarding Lupinus argenteus with chemical analysis and laboratory assays to test three hypotheses for the presence of pollen defense compounds: (1) these compounds are the result of spillover from adjacent tissues, (2) they protect against pollen thieves, and (3) they act as antimicrobial compounds. We also tested whether pollen defense compounds affect pollinator behavior. We found a positive relationship between alkaloid concentrations in pollen and petals, supporting the idea that pollen defense compounds partly originate from spillover. However, pollen and petals exhibited quantitatively (but not qualitatively) distinct alkaloid profiles, suggesting that plants can adjust pollen alkaloid composition independently from that of adjacent tissues. We found no relationship between pollen alkaloid concentration and the abundance of pollen thieves in Lupinus flowers. However, pollen alkaloids were negatively associated with bacterial abundance. Finally, plants with more alkaloids in their pollen received more pollinator visits, but these visits were shorter, resulting in no change in the overall number of flowers visited. We propose that pollen defense compounds are partly the result of spillover from other tissues, while they also play an antimicrobial role. The absence of negative effects of these compounds on pollinator visitation likely allows their maintenance in pollen at relatively high concentrations. Taken together, our results suggest that pollen alkaloids affect and are mediated by the interplay of multiple interactions.


Assuntos
Lupinus , Pólen , Polinização , Pólen/química , Animais , Lupinus/química , Lupinus/fisiologia , Alcaloides , Flores/química , Abelhas/fisiologia , Insetos/fisiologia , Insetos/efeitos dos fármacos
7.
Integr Zool ; 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39011657

RESUMO

Natural native forests are rapidly being replaced by anthropogenic forests often with a strong presence of invasive alien plant species. Eucalypt species are widely planted worldwide, with Eucalyptus globulus plantations being particularly expressive in Portugal. Poor forestry practices often lead to the associated expansion of invasive species, such as Acacia dealbata. However, we still know relatively little about the functioning of anthropogenic forests, such as seed and pollen dispersal services. Here, we compared bird abundance and richness and the seed and pollen dispersal networks in both forest types. Anthropogenic forests presented lower bird abundance, and smaller, more simplified, and more random (abundance-based) seed dispersal services than those of natural forests. Interestingly, the pollen dispersal network was more similar than the seed dispersal network for both forest types and dominated by opportunistic and neutral processes, given the absence of specialized nectarivorous. The proportion of birds transporting seeds decreased, while those carrying pollen significantly increased in the anthropogenic forest compared to the native forest. Our work highlights the impact of anthropogenic forests on bird abundance, with consequences for seed dispersal services and forest regeneration.

8.
Rev. biol. trop ; 71(1)dic. 2023.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1449507

RESUMO

Introducción: La frugivoría es un proceso ecológico determinante para la estructuración y regeneración de los bosques. En los trópicos, donde la diversidad de plantas y animales frugívoros es alta, las relaciones interespecíficas son complejas y requieren estudio. Objetivo: Identificar las especies de plantas ecológicamente importantes en dos redes de interacción, y el papel de los rasgos funcionales de los frutos en esas interacciones en un bosque seco. Métodos: Recolectamos 10 frutos por planta de 10 plantas de cada especie de interés en un bosque seco colombiano, calculamos el índice de importancia de las plantas a partir de la relevancia de aves y mamíferos frugívoros en la estructura de las redes. Esta relevancia se relaciona directamente con el potencial del animal como dispersor efectivo de semillas. Utilizamos modelos lineales generalizados para estimar el tamaño, color, estrato, y tipo de pulpa, en el índice. Resultados: Las plantas más importantes son especies de los géneros Miconia, Ficus, Cecropia, Bursera, Casearia y Trichilia, también identificadas como recursos importantes para los frugívoros de los trópicos en otros estudios. Las plantas con frutos carnosos, rojos y de menor tamaño son los mejores para dispersores de semillas. El índice de importancia de las plantas tiene alta variación; esto sugiere que un conjunto de especies frugívoras beneficiadas por cada especie de planta tiene una contribución diferenciada en procesos ecológicos derivados de la dispersión de semillas. Conclusiones: Programas de restauración para este tipo de bosque tropical seco debería incluir una variedad de plantas, incluyendo especies con frutos pequeños, rojos y carnosos.


Introduction: Frugivory is a pivotal ecological process for the structure and regeneration of forests. In the tropics, where the diversity of plants and frugivorous animals is high, interspecific relationships in the interaction networks are complex and need study. Objective: To identify ecologically important plant species in two interaction networks, and the role of functional fruit traits in those interactions in a dry forest. Methods: We collected 10 fruits per plant from 10 plants of each species of interest in a Colombian dry forest, we calculated the Plant Importance Index based on the bird and mammal frugivores relevance for network structure. This relevance is directly related to the animal's potential as effective seed dispersers. We used generalized linear models to estimate the effect of fruit size, color, stratum, and type of pulp, on the index. Results: The most important plants are species of the genera Miconia, Ficus, Cecropia, Bursera, Casearia and Trichilia, also identified as important resources for tropical frugivores in other studies. Plants with small, red, and fleshy fruits are the best for seed dispersers. The plant importance index has a high variation; this suggests that the set of frugivore species benefited by each plant species has a differential contribution to the ecological processes derived from seed dispersal. Conclusions: Restoration programs for this kind of tropical dry forest should include a variety of plants, including species with small, red, and fleshy fruits.

9.
Biota Neotrop. (Online, Ed. ingl.) ; 22(spe): e20221399, 2022. graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1403638

RESUMO

Abstract Since its inception, biodiversity has largely been understood as species diversity and assessed as such. Interactions among species or functional groups are gradually becoming part of an expanded concept of biodiversity. As a case study of the development of a research program in biodiversity, we summarize our multi-decade studies on interactions of Asteraceae and flowerhead-feeding insects in Brazil. Initially, host species were treated as independent replicates in order to assess the local and turnover components of their herbivore diversity. Research then expanded into sampling entire interactive communities of host plants and their associated herbivores in different localities and regions, enabling new research lines to be pursued. Interaction diversity could be assessed and factored into spatial and among-host components, suggesting a new field of interaction geography. Second, host specialization, a key component of interaction diversity, was reframed considering simultaneously relatedness and local availability of plant hosts. Third, with the influence of complex network theory, community-wide species interactions were probed for topological patterns. Having identified the modular structure of these plant-herbivore systems, later we demonstrated that they fit a compound hierarchical topology, in which interactions are nested within large-scale modules. In a brief survey of research funded by Fapesp, especially within the Biota-Fapesp program, we highlight several lines of internationally recognized research on interaction diversity, notably on plant-frugivore and plant-pollinator interactions, together with new theoretical models. The interplay of field studies with new theoretical and analytical approaches has established interaction diversity as an essential component for monitoring, conserving and restoring biodiversity in its broader sense.


Resumo Desde seu início, a biodiversidade geralmente tem sido entendida e avaliada principalmente como diversidade de espécies. Interações entre espécies ou grupos funcionais vêm sendo incorporadas em um conceito expandido de biodiversidade. Como um estudo de caso da evolução de um programa de pesquisa em biodiversidade, resumimos aqui nossos estudos das interações de Asteráceas com insetos endófagos em capítulos no Brasil, desenvolvidos por várias décadas. Inicialmente a diversidade de herbívoros foi estimada em diferentes espécies hospedeiras, tratando-as como réplicas independentes para estimar os componentes locais e de substituição da diversidade dos insetos associados. Posteriormente, passamos a amostrar comunidades interativas de plantas e insetos associados em diferentes localidades e regiões, o que abriu novas linhas de investigação. A diversidade de interações, agora fatorada em componentes espaciais e inter-hospedeiras, sugere um novo campo, a geografia de interações. Em segundo lugar, um componente essencial da diversidade de interações, a especialização trófica, foi redefinida como função da contiguidade filogenética bem como da disponibilidade local de plantas hospedeiras. Terceiro, sob influência da teoria de redes complexas, foram investigados padrões topológicos de comunidades interativas. Identificamos a estrutura modular dessas comunidades de plantas e herbívoros; posteriormente, demonstramos a topologia hierárquica dessas interações, composta por módulos internamente aninhados. Numa revisão sucinta de pesquisas sustentadas pela Fapesp, especialmente no programa Biota-Fapesp, destacamos diversas linhas de pesquisa sobre diversidade de interações que alcançaram reconhecimento internacional, tais como interações de plantas e frugívoros ou polinizadores, além de novos modelos teóricos. A conjugação de estudos de campo com novas abordagens teóricas e analíticas firmou a diversidade de interações como um componente essencial para monitorar, conservar e restaurar a biodiversidade em seu sentido mais amplo.

10.
Biota Neotrop. (Online, Ed. ingl.) ; 21(2): e20201109, 2021. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1285461

RESUMO

Abstract: Florivory can alter plant reproductive success by damaging sexual reproductive structures and disrupting plant-pollinator interactions through decreased flower attractiveness. Here, we report new records of the cactus Tacinga inamoena flower consumption by the Tropidurus hispidus lizard in the Brazilian Caatinga. We monitored 53 flowers from 11 T. inamoena individuals with camera traps over a 1-year period, totalling 450 camera-days of sample effort. We detected four florivory events. In three of these events, flowers were entirely consumed or had their reproductive structures severely damaged, leading to no fruit formation. Florivory events occurred in the morning, right after anthesis, in flowers near the ground, and lizards did not climb the cactus. Our results suggest that T. hispidus florivory on T. inamoena could have a negative impact on fruit set, since the consumed flowers were entirely destroyed. However, the long-term effects of florivory by lizards on T. inamoena reproductive success in the Caatinga still needs to be elucidated.


Resumo: A florivoria pode alterar o sucesso reprodutivo da planta através de danos às estruturas reprodutivas sexuais e interrupção das interações planta-polinizador por meio da diminuição da atratividade das flores. Aqui, relatamos novos registros de consumo de flores da cactácea opuntióide Tacinga inamoena pelo lagarto Tropidurus hispidus na Caatinga brasileira. Nós monitoramos 53 flores de 11 indivíduos de T. inamoena com armadilhas fotográficas por um período de um ano, totalizando 450 dias-câmera de esforço amostral. Detectamos quatro eventos de florivoria. Em três desses eventos, as flores foram totalmente consumidas ou tiveram suas estruturas reprodutivas severamente danificadas, não levando à formação de frutos. Os eventos de florivoria ocorreram pela manhã, logo após a antese, em flores próximas ao solo, e os lagartos não escalaram o cacto. Nossos resultados sugerem que a florivoria de T. hispidus em T. inamoena pode ter um impacto negativo na frutificação, uma vez que as flores consumidas foram totalmente destruídas. No entanto, os efeitos a longo prazo da florivoria por lagartos sobre o sucesso reprodutivo de T. inamoena na Caatinga ainda precisam ser elucidados.

11.
Rev. biol. trop ; 66(4): 1683-1700, oct.-dic. 2018. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1003356

RESUMO

Resumen La selección mediada por herbívoros moldea la evolución de los caracteres defensivos en las plantas. El conocimiento acerca del rol de los herbívoros como mediadores de selección es escaso y más aún si se consideran los grupos funcionales de herbívoros. Los objetivos de este trabajo fueron (1) describir la variación en rasgos foliares entre poblaciones, entre plantas dentro de una población y a nivel sub-individual (intra-planta), (2) explorar la relación entre la variación en el nivel de herbivoría y rasgos foliares, (3) determinar la relación entre rasgos foliares y patrones de daño y (4) estimar los regímenes de selección por diferentes grupos funcionales de herbívoros. Realizamos este estudio en cuatro poblaciones de Vassobia breviflora en el noroeste de Argentina (Yungas). Los rasgos foliares considerados fueron: tamaño, área foliar (af), forma (relación longitud/ancho de la hoja; laf) y proporción de área foliar removida (pafr) (N = 1 582 hojas, 57 plantas). Los herbívoros consumieron 15.6 % del área foliar y 76.8 % de la variación en la pafr ocurrió a nivel sub-individual. El patrón de daño fue dominado por herbívoros cortadores (70 %), seguido de un patrón de herbivoría punteada (22 %), 5 % mixto y 1 % minador. Se detectó selección no lineal para laf (γii = -0.180, EE = 0.76, P < 0.05), y selección correlacional entre el daño cortador y af (γij = -1.297, SE = 0.62, P < 0.05) y entre el daño punteado y af (γij= -1.130, SE=0.76, P < 0.05). La selección natural favoreció plantas con hojas pequeñas y alta remoción foliar y hojas grandes con menor daño y se detectó selección en contra de hojas grandes con mayor daño. Además, deducido de la relación entre el tipo de daño y la adecuación relativa, la selección favorecería el daño punteado por sobre el cortador. Las plantas resolverían el conflicto con los herbívoros según el tipo de daño y la selección natural regularía el despliegue foliar como una estrategia para lidiar con la diversidad de herbívoros.(AU)


Abstract Herbivore mediated-selection shapes the evolution of defensive plant traits. Knowledge about the role of herbivores as mediators of selection is scarce and even more if herbivore functional groups are considered. The objectives of this work were (1) to describe the variation in foliar traits between populations and both between and intra-plants within a population, (2) to explore the relationship between the variation in the herbivory level and foliar traits, (3) to determine the relationship between leaf traits and damage patterns and (4) estimate the selection regimes by different herbivore functional groups. We conducted this study in four populations of Vassobia breviflora in Northwestern Argentina (Yungas). The foliar traits considered were size, leaf area (af), shape (leaf length / width ratio; laf) and proportion of leaf area removed (pafr) (N = 1 582 leaves, 57 plants). The herbivores consumed 15.6 % of the leaf area and 76.8 % of the variation in the pafr occurred at the sub-individual level. The damage pattern was dominated by cutter herbivores (70 %), followed by a dotted herbivory pattern (22 %), mixed 5 % and 1 % miner. Nonlinear selection was detected for laf (γii = -0.180; EE = 0.76; P < 0.05), and correlational selection between the cutter damage and af (γij = -1.297; SE = 0.62; P < 0.05) and between the dotted damage and af (γij = -1.130; SE = 0.76; P < 0.05). Natural selection favored plants with small leaves and high foliar removal and large leaves with less damage and selection against larger leaves with greater damage was detected. In addition, deduced from the relationship between the damage type and the relative fitness, the selection would favor the dotted damage over the cutter one. The plants would resolve the conflict with the herbivores according to the damage type and natural selection would regulate the foliar display as a strategy to deal with the herbivore diversity.(AU)


Assuntos
Plantas , Biodiversidade , Herbivoria , Variação Biológica da População , Argentina
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