78 research outputs found

    Phenotypic matching in ovipositor size in the parasitoid Galeopsomyia sp. (Hymenoptera, Eulophidae) attacking different gall inducers

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    O tamanho do ovipositor dos parasitoides influencia a escolha do hospedeiro. Parasitoides que atacam hospedeiros expostos tendem a ter ovipositores menores em relação aos que precisam perfurar algum tipo de substratos ou tecidos como o das galhas. Como a maioria dos estudos trata esse assunto em nível interespecífico, o objetivo deste trabalho foi testar a variação intraespecífica e acoplamento fenotípico no tamanho do ovipositor de Galeopsomyia sp. no ataque a galhas. Foram amostradas galhas coletadas em Guapira opposita (Nyctaginaceae), planta hospedeira de cinco espécies de galhadores: Bruggmannia elongata, B. robusta, B. acaudatae duas espécies não descritas de Bruggmannia (sp. 1 e sp. 2) (Diptera, Cecidomyiidae). Em cada transecção, todas as galhas das 30 primeiras plantas encontradas foram coletadas e acondicionadas em saco plástico até a emergência dos parasitoides. Foram feitas 15 amostragens ao longo de dois anos. As larvas de último ínstar dos galhadores, espessura das galhas, assim como o tamanho do ovipositor dos indivíduos de Galeopsomyia sp. foram medidos. Não foi encontrada diferença para o tamanho das larvas entre espécies de galhador. Porém, as galhas de Bruggmannia sp. 1 e sp. 2 foram significativamente mais espessas que as de B. acaudata e essas mais espessas que as de B. elongata e B. robusta. Os tamanhos do ovipositor diferiram significativamente para vespas emergidas das galhas de Bruggmannia sp. 1 e sp. 2 em relação às demais. A dimensão do hospedeiro é fundamental para determinar o tamanho do parasitoide, mas neste caso o tamanho do hospedeiro não variou, e sim a espessura do tecido a ser perfurado. Galhas mais espessas foram atacadas por parasitoides maiores e com ovipositor mais longo, indicando acoplamento fenotípico. Assim, espessuras maiores de galha parecem estar selecionando indivíduos maiores da população, o que pode ter consequências evolutivas importantes a longo prazo.Parasitoid ovipositor size importantly affects host choice; those attacking exposed hosts usually have shorter ovipositors compared to those needing drilling deeper through substrates such as plant tissue and gall tissue. Most studies treat this theme at the interspecific level, and the aim of this work was to test for intraspecific variation and phenotypic matching in ovipositor size for Galeopsomyia sp. attacking galls. Galls were sampled from Guapira opposita(Nyctaginaceae), a host plant to five species of Bruggmannia gallers (Diptera, Cecidomyiidae) in southern Brazil: Bruggmannia elongata, B. robusta, B. acaudata, and two undescribed species of Bruggmannia (sp. 1 and sp. 2). On forest transects, all galls from the 30 first galled plants found were sampled and kept in sealed plastic bags until parasitoid emergence. A total of 15 samples were done along two years. We measured galler last instar larvae length and gall thickness for each galling species, and ovipositor length for all Galeopsomyia sp. individuals emerging from the galls. There were no differences in larval length among galler species. However, Bruggmannia sp. 1 and sp. 2 galls were significantly thicker than those of B. acaudata, and the latter thicker than both B. elongata and B. robusta galls. Wasp ovipositor size differed significantly between those coming from Bruggmannia sp. 1 and sp. 2 galls relative to all others. Host extended phenotype size is thus fundamental to determine parasitoid size, but in this case host (larval) size does not change among species, although gall thickness was different. Thicker galls were attacked by larger parasitoids with longer ovipositors, denoting phenotypic matching. Thicker galls appear to be selecting larger parasitoid individuals, which in the long run can lead to important evolutionary change as well

    Combining functional traits and phylogeny to disentangling Amazonian butterfly assemblages on anthropogenic gradients

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    Environmental gradients consist of sequential changes in the physical and structural characteristics of a region. These allow us to follow species responses and tolerances under different habitat conditions. Among them, forest fragmentation and succession comprise the most common examples of forest gradients, where organismal responses require distinct morphological, physiological, and behavioral adaptations. However, environmental changes can impose ecological and evolutionary constraints that act on species traits, as well as on local species assemblies through their phylogenetic history. In this study, we evaluated the differences in species distribution and composition on fruit-feeding butterfly assemblages along forest fragmentation and succession gradients. We combine functional and phylogenetic methods for determining butterfly assemblages, and inferred species resistance and resilience according to habitat changes in tropical forests. We used a database of 471 fruit-feeding butterflies of 60 species sampled from different environments in the central Amazon rainforest. A total of 13 functional traits were measured, and a phylogenetic tree was obtained for the sampled species. The trait–environment relationship was analyzed along both forest fragmentation and succession gradients, controlling for phylogenetic signal on species distribution and functional composition when necessary. Several traits presented phylogenetic signal, and phylogeny was also driving butterfly species distribution along the successional gradient. After controlling for phylogeny, individual characteristics related to flight speed (thoracic weight) and antipredatory strategies (camouflage) increased in early-successional forests, with large butterflies (body length) prevailing in primary forests. No clear functional and phylogenetic pattern was identified for the fragmentation gradient. Our results are consistent with the idea that butterflies may be employing distinct functional strategies to attenuate habitat change effects. Larger butterflies, with lower dispersal ability, are preferentially susceptible to local extinctions in the early-successional environments, mainly when forested habitat and its resources become spatially restricted. In addition, several anti-predatory strategies related to conspicuous colors may be losing their functionality in open areas, where not being distinctive against the background becomes the primary defense against predation

    Insetos indutores de galhas das florestas decidual e semidecidual no Estado do Rio Grande do Sul, Brasil

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    Galls are specific changes induced by insects on plant organs mainly through increases in plant cell number and/or size. Gall diversity is easy to recognize in the field because gallers are mostly species-specific, and thus each gall morphotype can be a proxy for a galling species. Insect galls are virtually unknown in Seasonal Deciduous and Semi-Deciduous forests of southern Brazil. Here, galls and host plants were surveyed between 2015 and 2017 in four forest fragments of Rio Grande do Sul State in these two vegetation types, in secondary-growth and areas under restoration. We recorded 89 gall morphotypes, with gallers belonging to Lepidoptera and Diptera, with the latter represented mainly by Cecidomyiidae. Galls were associated to 46 plant species in 27 families. Asteraceae, Piperaceae, Fabaceae, Myrtaceae and Lauraceae were the richest families in terms of galls, whilst Piper aduncum and Mikania glomerata were superhosts. Most galls occurred in leaves and shoots. The most common shapes were fusiform, globoid and lenticular. Forty-eight gall morphotype records are new for both Rio Grande do Sul and Brazil, an expressive number considering only two seasonal forest types sampled and few sampling points, showing how important surveys still are for these little know fauna both in taxonomic and ecological terms.Galhas são alterações específicas induzidas por insetos sobre órgãos das plantas principalmente através de aumento no número e/ou tamanho das células vegetais. A diversidade de galhas é reconhecível em campo porque os galhadores são na sua vasta maioria espécie-específicos e assim cada morfotipo de galha serve como proxy para uma espécie de galhador. Insetos galhadores são virtualmente desconhecidos nas florestas estacionais deciduais e semideciduais do sul do Brasil. Galhas e plantas hospedeiras foram inventariadas entre 2015 e 2017 em quarto fragmentos florestais do Estado do Rio Grande do Sul nestas duas formações vegetacionais, em áreas com sucessão secundária e sob restauração. Foram encontrados 89 morfotipos de galhas, com galhadores pertencentes a Lepidoptera e Diptera, com os últimos representados principalmente por Cecidomyiidae. As galhas estiveram associadas a 46 espécies de plantas em 27 famílias. Asteraceae, Piperaceae, Fabaceae, Myrtaceae e Lauraceae foram as famílias mais ricas em termos de galhas, sendo Piper aduncum e Mikania glomerata considerados super-hospedeiras. A maioria das galhas ocorreu em folhas e ramos. As formas mais comuns foram fusiforme, globoide e lenticular. Dos morfotipos de galhas registrados, 48 são novos para o Rio Grande do Sul e o Brasil, um número expressivo considerando que somente dois tipos de florestas foram amostradas em um número restrito de pontos amostrais, demonstrando a importância de levantamentos para esta fauna quase desconhecida tanto em termos taxonômicos quanto ecológicos

    Long-term ecological research in southern Brazil grasslands: effects of grazing exclusion and deferred grazing on plant and arthropod communities

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    Grazing exclusion may lead to biodiversity loss and homogenization of naturally heterogeneous and species-rich grassland ecosystems, and these effects may cascade to higher trophic levels and ecosystem properties. Although grazing exclusion has been studied elsewhere, the consequences of alleviating the disturbance regime in grassland ecosystems remain unclear. In this paper, we present results of the first five years of an experiment in native grasslands of southern Brazil. Using a randomized block experimental design, we examined the effects of three grazing treatments on plant and arthropod communities: (i) deferred grazing (i.e., intermittent grazing), (ii) grazing exclusion and (iii) a control under traditional continuous grazing, which were applied to 70 x 70 m experimental plots, in six regionally distributed blocks. We evaluated plant community responses regarding taxonomic and functional diversity (life-forms) in separate spatial components: alpha (1 x 1 m subplots), beta, and gamma (70 x 70 m plots), as well as the cascading effects on arthropod high-taxa. By estimating effect sizes (treatments vs. control) by bootstrap resampling, both deferred grazing and grazing exclusion mostly increased vegetation height, plant biomass and standing dead biomass. The effect of grazing exclusion on plant taxonomic diversity was negative. Conversely, deferred grazing increased plant taxonomic diversity, but both treatments reduced plant functional diversity. Reduced grazing pressure in both treatments promoted the break of dominance by prostrate species, followed by fast homogenization of vegetation structure towards dominance of ligneous and erect species. These changes in the plant community led to increases in high-taxa richness and abundance of vegetation-dwelling arthropod groups under both treatments, but had no detectable effects on epigeic arthropods. Our results indicate that decision-making regarding the conservation of southern Brazil grasslands should include both intensive and alleviated levels of grazing management, but not complete grazing exclusion, to maximize conservation results when considering plant and arthropod communities

    Use of multivariate statistical methods for classification of olive oil

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    Multivariate statistical methods can contribute significantly to classification studies of extra virgin and common olive oil groups. Therefore, nuclear magnetic resonance (NMR) was used to discriminate olive oil samples, multivariate statistical techniques Principal Component Analysis - PCA, Fuzzy Cluster, Silhouette Validation Method to describe and classify. The groups' distinction into organic and common was observed by applying the non-hierarchical Fuzzy grouping with a distinction between the two groups with a 65% confidence interval. The validation was performed by the silhouette index that presented S (i) of 0.73, which showed that the adopted grouping presented adequate strength and distinction criterion. However, PCA only analyzed the behaviors of data from extra virgin olive oil. Thus, the Fuzzy clustering method was the most suitable for classifying extra virgin olive oil

    12,500+ and counting: biodiversity of the Brazilian Pampa

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    Knowledge on biodiversity is fundamental for conservation strategies. The Brazilian Pampa region, located in subtropical southern Brazil, is neglected in terms of conservation, and knowledge of its biodiversity is fragmented. We aim to answer the question: how many, and which, species occur in the Brazilian Pampa? In a collaborative effort, we built species lists for plants, animals, bacteria, and fungi that occur in the Brazilian Pampa. We included information on distribution patterns, main habitat types, and conservation status. Our study resulted in referenced lists totaling 12,503 species (12,854 taxa, when considering infraspecific taxonomic categories [or units]). Vascular plants amount to 3,642 species (including 165 Pteridophytes), while algae have 2,046 species (2,378 taxa) and bryophytes 316 species (318 taxa). Fungi (incl. lichenized fungi) contains 1,141 species (1,144 taxa). Animals total 5,358 species (5,372 taxa). Among the latter, vertebrates comprise 1,136 species, while invertebrates are represented by 4,222 species. Our data indicate that, according to current knowledge, the Pampa holds approximately 9% of the Brazilian biodiversity in an area of little more than 2% of Brazil’s total land The proportion of species restricted to the Brazilian Pampa is low (with few groups as exceptions), as it is part of a larger grassland ecoregion and in a transitional climatic setting. Our study yielded considerably higher species numbers than previously known for many species groups; for some, it provides the first published compilation. Further efforts are needed to increase knowledge in the Pampa and other regions of Brazil. Considering the strategic importance of biodiversity and its conservation, appropriate government policies are needed to fund studies on biodiversity, create accessible and constantly updated biodiversity databases, and consider biodiversity in school curricula and other outreach activitie

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Mapping density, diversity and species-richness of the Amazon tree flora

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    Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution
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