286 research outputs found
Is the taxonomy of Brachycephalus (Anura: Brachycephalidae) in need of rescue? A reply to Condez et al. (2017)
No full textPie, Marcio R., Ribeiro, Luiz F., Bornschein, Marcos R. (2017): Is the taxonomy of Brachycephalus (Anura: Brachycephalidae) in need of rescue? A reply to Condez et al. (2017). Zootaxa 4350 (3): 587-589, DOI: 10.11646/zootaxa.4350.3.1
Phylogenetic diversity and the structure of host-epiphyte interactions
No full textThis repository contains code, and data used in the paper "Phylogenetic diversity and the structure of host-epiphyte interactions!", by Marcio R. Pie, Fernanda S. Caron, Sven P. Batke, Johan Reyes-Chávez, Thom Dallimore et al. Use the following link: https://github.com/fernandacaron/epi_evo
The macroevolution of climatic niches and its role in ant diversification
No full textInvestigating how climatic niches change over evolutionary timescales is a necessary step to understanding the current distribution of lineages, yet few studies have addressed this issue using comprehensive datasets. In this study, the evolution of ant climatic niches is investigated at a global scale based on bioclimatic data associated with 163481 ant occurrence records. The resulting dataset was subjected to principal component analysis, and the scores obtained were used to characterise the main axes of ant climatic niche evolution. Principal component axis 1 (PC1) reflected variation in average temperature and seasonality - consistent with typical tropical/temperate gradients - whereas PC2 was associated with varying levels of aridity. Evolution along these two niche axes was markedly different: differences in the amount of explained variance between PC1 (65%) and PC2 (19%) suggest that climatic niche evolution was nearly three times more pronounced along a tropical-temperate climate axis. There was statistically significant phylogenetic signal on PC1, with genera occupying more tropical conditions diversifying at a faster rate, yet neither of these results is significant on PC2. In addition, most of the ancient ant lineages are associated with conditions of low seasonality and high temperatures. These results provide partial support for the tropical conservatism hypothesis as an explanation for geographical patterns of ant species richness.</p
Phylogenetic diversity and the structure of host-epiphyte interactions across the Neotropics
No full textUnderstanding the mechanisms driving community assembly has been a major focus of ecological research for nearly a century, yet little is known about these mechanisms in commensal communities, particularly with respect to their historical/evolutionary components. Here, we use a large-scale dataset of 4,440 vascular plant species to explore the relationship between the evolutionary distinctiveness (ED) (as measured by the ’species evolutionary history’ (SEH)) of host species and the phylogenetic diversity (PD) of their associated epiphyte species. Although there was considerable variation across hosts and their associated epiphyte species, they were largely unrelated to host SEH. Our results mostly support the idea that the determinants of epiphyte colonization success might involve host characteristics that are unrelated to host SEH (e.g., architectural differences between hosts). While determinants of PD of epiphyte assemblages are poorly known, they do not appear to be related to the evolutionary history of host species. Instead, they might be better explained by neutral processes of colonization and extinction. However, the high level of phylogenetic signal in epiphyte PD (independent of SEH) suggests it might still be influenced by yet unrecognized evolutionary determinants. This study highlights how little is still known about the phylogenetic determinants of epiphyte communities
Formigas cultivadoras de fungos: estado da arte e direcionamento para pesquisas futuras.
No full textA tribo Attini (Hymenoptera: Formicidae) compreende 14 gêneros com aproximadamente 230 espécies de formigas descritas que estão envolvidas em um mutualismo obrigatório com fungos. Este fungo é cultivado no interior das colônias para a alimentação das formigas, e tem como substrato uma variedade de material orgânico. O fungo é utilizado na dieta das formigas, que em retribuição fornecem ao fungo substratos para o crescimento, proteção contra parasitas ou competidores e asseguram a sua reprodução. Embora todas as espécies da tribo cultivem fungo, essas formigas são bastante heterogêneas em relação ao sistema de agricultura, tamanho da colônia e estrutura social, métodos de cultivo do fungo, forrageamento, etc. Nesta revisão são discutidas as principais características da agricultura, simbiose e história natural das formigas cultivadoras de fungos, bem como o direcionamento para as pesquisas futuras com essas formigas.Artigo de revisão
A null model of morphospace occupation.
No full textProgress in understanding the relationship between lineage diversity, morphological diversity, and morphospace dynamics has been hampered by the lack of an appropriate null model of morphospace occupation. In this article, we introduce a simple class of models based on branching random walks (BRWs) for continuous traits. We show that many of the observed patterns of morphospace occupation might be simply a consequence of the dynamics of BRWs and therefore might not require special explanations. We also provide expected patterns of morphospace occupation according to a number of different conditions. In particular, we model BRWs on neutral landscapes and demonstrate that clumping in morphospace is possible even in the absence of adaptive landscapes with well-defined peaks and valleys. The quantitative definition of the BRW provides a means to analyze, both computationally and analytically, patterns of morphospace occupation according to different hypotheses.</p
Conectividade do caranguejo Grapsus grapsus (Linnaeus, 1758) em ilhas oceânicas brasileiras
Get PDFDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-Graduação em EcologiaO ambiente marinho favorece a troca de indivíduos entre as populações promovendo a conectividade entre elas, o que pode contribuir para esforços na conservação. No Brasil, as ilhas oceânicas (Atol das Rocas (RA), Fernando de Noronha (FN), Arquipélago de São Pedro e São Paulo (SPSPA) e Ilha da Trindade (TR)) têm diferentes estratégias de conservação. O caranguejo Grapsus grapsus (Linnaeus, 1758), no Brasil, ocorre somente nestas ilhas oceânicas, além disso, ele dispersa apenas no estágio larval e depois passa a fase adulta nos costões rochosos. Portanto, essa espécie não se utiliza de trampolins ecológicos submersos e precisa das correntes marinhas superficiais para dispersão. Para entendermos o papel do oceano para cada espécie é importante estudarmos as diferenças genéticas e morfológicas entre as populações. O objetivo deste estudo foi verificar o nível de diferenças genéticas e morfométricas entre as populações do caranguejo G. grapsus em todas as ilhas oceânicas brasileiras e esclarecer o "status" de identificação da população na Ilha da Trindade. Além disso, nós também avaliamos esta espécie como modelo de conectividade para o planejamento de áreas marinhas protegidas. Assim, um total de 564 indivíduos de G. grapsus foi utilizado nas análises morfométricas e 84 nas análises genéticas. O DNA genômico utilizado foi um fragmento de 570bp da região controle do mtDNA. As análises morfométricas mostraram similaridade entre as populações do SPSPA e TR, tanto para os machos quanto para as fêmeas. Considerando os aspectos genéticos, SPSPA foi o local com maior diversidade haplotípica, enquanto TR foi o menos diverso. Além disso, este último local apresentou haplótipos exclusivos, enquanto as outras ilhas compartilharam alguns. Diferentes padrões encontrados na genética e na morfometria são comuns em caranguejos decápodos. Consequentemente, é importante combinarmos análises morfométricas e genéticas quando comparamos populações, para uma visão mais completa sobre sua diferenciação. G. grapsus aparenta ser capaz de dispersar livremente entre as ilhas brasileiras equatoriais, onde a distância é relativamente curta, mas incapaz de alcançar ilhas muito distantes. Portanto, TR é um local importante para a manutenção de G. grapsus, pois representa um estoque genético com haplótipos diferenciados o que é essencial para a manutenção da diversidade genética da espécie e, portanto, ela deveria ser objeto de maior atenção
Lek behavior as the mating strategy of Setellia sp. (Diptera:Richardiidae)
No full textA field study revealed that the mating system of the richardiid Setellia sp. meets even the most stringent definition of lek behavior. Males remain on the upper surface of the leaves of Saranthe aff. klotzchiana (Maranthaceae), where they perform ritualized displays related to courtship and territorial behavior. Correlational data support the existence of reproductive dominance hierarchies, which are based on both male vs. male and female vs. female agonistic interactions. Curiously, the behavioral acts performed by Setellia sp. show remarkable similarities to other nonrelated dipteran lekkers. Aspects of evolution and convergence of these behaviors in the Acalyptratae are considered.</p
The influence of phylogenetic uncertainty on the detection of positive darwinian selection
No full textThe power of maximum likelihood tests of positive selection on protein-coding genes depends heavily on detecting and accounting for potential biases in the studied data set. Although the influence of transition: transversion and codon biases have been investigated in detail, little is known about how inaccuracy in the phylogeny used during the calculations affects the performance of these tests. In this study, 3 empirical data sets are analyzed using sets of simulated topologies corresponding to low, intermediate, and high levels of phylogenetic uncertainty. The detection of positive selection was largely unaffected by errors in the underlying phylogeny. However, the number of sites identified as being under positive selection tended to be overestimated.</p
Behavioral repertoire, age polyethism and adult transport in Ectatomma opaciventre (Formicidae:Ponerinae)
No full textThis study describes the behavioral repertoire of a mature colony of Ectatomma opaciventre Roger. Twenty-eight different behavioral acts were recorded from 4538 individual observations. There was evidence of age polyethism, with young workers performing significantly more brood care and allogrooming than older workers. Experiments were also performed to investigate the behavioral organization of nest relocation in E. opaciventre. This complex social behavior was regulated by a few workers which specialized in transporting nestmates, including other workers, winged gynes, males, and the queen. Winged gynes were also observed performing adult transport. The carrying posture utilized in E. opaciventre is similar to that in other ponerines, although some idiosyncratic features were detected.</p
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