Papers by Marcilio Fagundes
Biodiversitas Journal of Biological Diversity
The role of interspecific competition in the organization of herbivorous insect communities may v... more The role of interspecific competition in the organization of herbivorous insect communities may vary depending on resource availability. Trees are structurally more complex and have greater resource availability for herbivorous insects than shrubs. In this study, we evaluated the roles of plant architecture and interspecific interactions on community organization of the gall-inducing insect associated with trees (adult plants) and shrubs (young plants) of Copaifera langsdorffii. Our results showed that the species composition of gall-inducing insect communities associated with C. langsdorffii differed statistically between trees and shrubs. In addition, the trees presented greater diversity of gall-inducing insects than the shrubs, corroborating the hypothesis of plant architecture. The results of the analysis of null models showed that the co-occurrence of gall-inducing insect species associated with trees not differ from the co-occurrence predicted by chance. Thus, interspecific interactions cannot be used to explain the community organization of the gall-inducing insects on C. langsdorffii trees. On the other hand, the co-occurrence of gall-inducing insect species differed from the co-occurrence predicted by chance when shrubs plants were analyzed, indicating that biotic interactions can shape the structure of the gall-inducing insect community on shrubs. The lower availability of oviposition sites probably generates a dispute for these resources among females of different species of gall-inducing insects only in the shrubs. Therefore, the role of competition in the organization of herbivore insect communities on their host plant may vary depending on the ontogenetic stage of the host plant.
Arthropod-Plant Interactions, 2012
ABSTRACT Plants use different defense strategies throughout their ontogenetic development. In thi... more ABSTRACT Plants use different defense strategies throughout their ontogenetic development. In this study, three questions were proposed: (1) Is there a greater abundance of ants on young leaves, which possess active extrafloral nectaries, than on mature leaves? (2) Do ants exert an indirect defense that is effective against the attack of herbivorous insects? (3) Do mature leaves have a greater concentration of physical and chemical defense than young leaves? These questions were addressed through an ant-exclusion experiment in which two branches of Copaifera langsdorffii (n = 25) were marked and monitored throughout the entire foliar expansion and development period. A reduction in the abundance of ants throughout foliar development was observed. The ants exerted an effective defense against herbivores on C. langsdorffii: the branches where ants were excluded had a greater number of herbivores. The mature leaves possessed a greater index of leaf sclerophylly than young leaves, but the leaves did not differ in the concentration of tannins. The foliar ontogeny of C. langsdorffii promoted an inversion in the defense strategy against herbivores, and despite showing an opportunistic relationship, the interaction between ants and extrafloral nectaries appears to play an important role in structuring the interactions between herbivorous insects and their host plants.
Ecología Austral, 2019
Gall-forming insects are sophisticated sedentary herbivores that present high level of specificit... more Gall-forming insects are sophisticated sedentary herbivores that present high level of specificity with host plant, but their performance can be affected by biotic and abiotic factors. In this study we have tested two predictions: a) plants that have a greater number of conspecific neighbors have greater richness and abundance of gall-forming insects, and b) interspecific competition is a force capable of shaping the organization of gall-forming insect communities in super-host plants. We used the Copaifera oblongifolia (Fabaceae)/galling insects' system to test these predictions. Fieldwork was carried out in areas of Cerrado (Brazilian Savanna) in northern Minas Gerais, Brazil. To test the first hypothesis, we evaluated with generalized linear mixed models, the effects of the number of conspecific neighbors on the richness and abundance of galls associated with 67 C. oblongifolia individual plants belonging to two populations. To test the second hypothesis, we used null models to evaluate whether a plant of C. oblongifolia colonized by a species of gall is preferred or avoided by another species of gall. A total of 2901 gall-forming insects belonging to 15 species were collected from the host plant C. oblongifolia. We observed negative relationships between the number of conspecific neighbors and the abundance and richness of gall-forming insects associated C. oblongifolia. Thus, our data did not support the resource concentration hypothesis. Instead, we used the resource dilution theory to explain the negative relation between resource concentration and frequency of attack by galling insects. Our results also showed that the co-occurrence pattern of gall-forming insects in the host plant did not differ from those expected by chance. Therefore, the structure of the gall-forming insect community associated to single C. oblongifolia plants cannot be attributed to deterministic factors such as interspecific competition.
Ecology and Evolution, 2018
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Journal of Insect Conservation
Understanding the factors that influence the diversity and composition of arthropod communities i... more Understanding the factors that influence the diversity and composition of arthropod communities is a major topic in ecology. Canopy arthropod communities are a major constituent of biodiversity and show great variation in time and space according to different factors. Recently, genetic variation within tree species has attracted attention as a significant factor determining the diversity and composition of canopy arthropod communities. A major source of genetic and phenotypic novelty in plant species is interspecific hybridization, and therefore it is of interest to evaluate how this process affects the communities of associated organisms. In this study, we used microsatellite markers and geometric morphometry of leaf shape to analyze genetic and morphological variation in 45 individuals in a local hybrid zone between the oaks Quercus affinis and Q. laurina in Mexico. Individual trees were assigned to one of the parental species or to the hybrid category. The percentage of leaf area removed by herbivores was quantified in each individual and the canopies of five individuals of each categeory (two parental species and hybrids) was fogged with insecticide to assess the diversity and composition of arthropod communities. Results indicated that hybrid trees experience higher levels of herbivory than parental species and also sustain a higher abundance and richness of canopy arthropods. In general, our study supports the “hybrid susceptibility hypothesis” that predicts a higher incidence of associated arthropods on hybrid plants than in their parental species as result of the disruption of co-adapted gene complexes associated to resistance traits.
PLOS ONE
Intraspecific trait variation has been singled out as an important mechanism by which individuals... more Intraspecific trait variation has been singled out as an important mechanism by which individuals can cope with environmental variations and avoid local extinctions. Here we evaluate variation in metamer traits (i.e., traits associated with internodes, petioles and their corresponding leaves) and parameters of chlorophyll fluorescence within and among populations of a neotropical tree, Copaifera langsdorffii. We also evaluated phenotypic plasticity in natural settings comparing traits between shade and sun-exposed metamers. We selected six populations along a climatic gradient ranging from semi-arid to humid and representing three different biomes (Caatinga, Cerrado, and Atlantic Forest). Local climatic conditions significantly affected the morphological and physiological traits of populations. Trait variation among populations was explained mainly by aridity index and evapotranspiration. Individuals from drier regions had lower specific leaf area (SLA), lower investment in leaf area per total dry mass of metamer (LARm), lower specific petiole length (SPL) and lower potential quantum yield (Fv/Fm, only for sun-exposed metamers). Populations from locations with greater environmental heterogeneity (interannual variation) had greater plasticity in response to light for Fv/Fm and electron transport rate (ETR) and morphological traits related to the hydraulic and biomechanical aspects of the leaves (petiole length, internode length and SPL). High intraspecific variation in metamer traits in C. langsdorffii coupled with its ability to modify these traits in response to different climate conditions can explain the success of the species over a range of different habitats and represent important factors for the persistence of this species in the face of climate change.
Ecologia Austral, Dec 1, 2013
Ecology and Evolution
rising knowledge about plant defenses, the role of competition has gained prominence (Kaplan & De... more rising knowledge about plant defenses, the role of competition has gained prominence (Kaplan & Denno, 2007; Murdoch, 1966; Reitz & trumble, 2002), and recent studies have highlighted the important role of competition for phytophagous insect community structure
Plant Species Biology, 2016
Um dos fatores que mais afetam a dinâmica dos fragmentos florestais é o efeito de borda, fisicame... more Um dos fatores que mais afetam a dinâmica dos fragmentos florestais é o efeito de borda, fisicamente caracterizado como uma alteração na composição e abundância relativa das espécies na parte marginal do fragmento (Formam & Godron, 1986). A ocorrência de uma borda afeta o resultado das interações entre espécies. Por exemplo, a maior incidência de luz na borda afeta a dinâmica dos meristemas das plantas, aumentando o número de gemas , que constituem recursos básicos para o desenvolvimento de insetos herbívoros (e.g. Espírito-Santo et al 2003). Além disso, as bordas encontram-se mais expostas a fatores estressantes como ventos, temperatura e variações na estrutura física do solo, que provocam alterações marcantes na fisiologia das plantas . Estes efeitos também podem estender para os níveis tróficos superiores, promovendo mudanças na organização das comunidades de herbívoros e seus parasitóides. Neste cenário e considerando-se a hipótese do estresse , plantas presentes na borda de um fragmento estariam mais vulneráveis ao ataque de herbívoros, onde devem ser esperadas maior riqueza e abundância de insetos herbívoros. Além disso, plantas situadas na borda poderiam crescer mais que aquelas situadas no interior do fragmento e, portanto, serem mais atacadas como previsto pela hipótese do vigor da planta . Desta forma, o objetivo deste trabalho foi verificar se existe o efeito de borda na taxa de crescimento e na comunidade de galhadores em um fragmento de Cerrado, uma vez que grande parte dos estudos foi realizada em florestas úmidas. Para isso será testada a hipótese de que plantas presentes na borda de um fragmento são mais atacadas por insetos galhadores se comparadas a plantas presentes no interior do fragmento. Assim, neste estudo foi comparada (1) a riqueza e a abundância de galhas associadas a C. langsdorffii no interior e na borda de um fragmento de Cerrado, (2) a taxa de crescimento das plantas nos dois ambientes e (3) verificado se existe relação da taxa de crescimento com a abundância e riqueza de galhas.
American Journal of Plant Sciences, 2014
Seed size is a plastic trait of the plants that directly affect seed germination and seedling rec... more Seed size is a plastic trait of the plants that directly affect seed germination and seedling recruitment. This study aimed to investigate the relationship between seed size, seed germinability and seedling performance of Copaifera langsdorffii by testing four hypotheses: 1) larger seeds have higher germination percentage; 2) smaller seeds require less time to germinate and for initial development of the seedlings; 3) larger seeds produce more vigorous seedlings and 4) seed size negatively affects seedling root/shoot ratio. In 2011, we selected 30 individuals of C. langsdorffii from which 300 seeds were randomly collected in the plant canopy. All these seeds were weighted and placed in germination tray using vermiculite as substrate. Seed germinability and initial development of seedlings were monitored daily until cotyledons fell. Small seeds have higher germination percentage and germinate faster when compared to large seeds. Nonetheless, seedlings originated from larger seeds have longer development times, resulting in more vigorous seedlings. In addition, seedlings originating from small seeds allocate proportionally greater amount of resources to roots when compared to larger seeds. The fact that small seeds have higher germination percentage and faster germination favors the colonization of transient habitats. However, larger seeds produce more vigorous seedlings, favoring the seedling establishment in more stable habitats. Thus, we argue that high variability in seed size of C. langsdorffii favors its widespread geographic distribution.
Neotropical Insect Galls, 2014
Ecol Entomol, 2005
1. The relative importance of direct and indirect interactions in controlling organism abundance ... more 1. The relative importance of direct and indirect interactions in controlling organism abundance is still an unresolved question. This study investigated the role of the direct and indirect interactions involving ants, aphids, parasitoids, and the host plant Baccharis dracunculifolia (Asteraceae) on a galling herbivore Baccharopelma dracunculifoliae (Homoptera: Psyllidae).
O objetivo deste trabalho foi caracterizar a diversidade de borboletas frugívoras em três fitofis... more O objetivo deste trabalho foi caracterizar a diversidade de borboletas frugívoras em três fitofisionomias adjacentes (cerrado, mata ciliar e mata seca) no norte de Minas Gerais, enfatizando o efeito da sazonalidade nestes habitats. Foram coletadas 5.249 borboletas (Eunica tatila representou 80%). A maior riqueza foi encontrada na mata ciliar (31 espécies) e abundância na mata seca (2.117 indivíduos). Comparativamente, a mata ciliar é a menos caducifólia e mais úmida. Em Maio (início da seca) observou-se maior riqueza de borboletas (31 espécies), provavelmente relacionada à maior disponibilidade de recursos na estação chuvosa, mas a maior abundância (2.888 indivíduos) ocorreu em setembro (final da seca), por fatores intrínsecos à biologia de E. tatila.
The genus Baccharis is composed of ca. 500 species which are distributed primarily in tropical Am... more The genus Baccharis is composed of ca. 500 species which are distributed primarily in tropical America. It is dioecious and highly diverse in chemistry, architecture, phenology and occupy many different niches across several gradients of light, temperature, humidity, altitude and succession. It is host to the most speciose galling fauna, with more than 121 galling species on 40 host plant. This system provide an ideal scenario to test several ecological hypotheses, including the long standing plant sexual differences on timing and intensity of energy allocation, vigor, architecture and herbivore attack. Moreover its wide distribution enables to test latitudinal and altitudinal gradients on gall attack. We review the studies performed on these Neotropical shrubs related to galling insects. These studies have been crucial for the establishment of generalities and testing of ecological and evolutionary theories across the Americas, as well as to generate new ideas and hypotheses. For these reasons and power of the field and experimental observations we suggest that the galling insects on their Baccharis hosts may represent a Neotropical model system for studies on insect plant interactions.
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Papers by Marcilio Fagundes