Community structure of mites (Arachnida: Acari) in six rubber tree clones

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

From cuckoos to chickens: a caught-in-the-act case of host shift in feather mites (Arachnida: Acari: Psoroptoididae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Competition and phylogeny determine community structure in Mullerian co-mimics

Until recently, the study of negative and antagonistic interactions (for example, competition and predation) has dominated our understanding of community structure, maintenance and assembly(1). Nevertheless, a recent theoretical model suggests that positive interactions (for example, mutualisms) may counterbalance competition, facilitating long-term coexistence even among ecologically undifferentiated species(2). Mullerian mimics are mutualists that share the costs of predator education(3) and are therefore ideally suited for the investigation of positive and negative interactions in community dynamics. The sole empirical test of this model in a Mullerian mimetic community supports the prediction that positive interactions outweigh the negative effects of spatial overlap(4) (without quantifying resource acquisition). Understanding the role of trophic niche partitioning in facilitating the evolution and stability of Mullerian mimetic communities is now of critical importance, but has yet to be formally investigated. Here we show that resource partitioning and phylogeny determine community structure and outweigh the positive effects of Mullerian mimicry in a species-rich group of neotropical catfishes. From multiple, independent reproductively isolated allopatric communities displaying convergently evolved colour patterns, 92% consist of species that do not compete for resources. Significant differences in phylogenetically conserved traits (snout morphology and body size) were consistently linked to trait-specific resource acquisition. Thus, we report the first evidence, to our knowledge, that competition for trophic resources and phylogeny are pivotal factors in the stable evolution of Mullerian mimicry rings. More generally, our work demonstrates that competition for resources is likely to have a dominant role in the structuring of communities that are simultaneously subject to the effects of both positive and negative interactions.

Horizontal and vertical tree community structure in a lowland atlantic rain forest, southeastern Brazil

A estrutura horizontal e vertical do componente arbóreo foi investigada em um trecho de Floresta Atlântica baixo-montana através de um levantamento fitossociológico em dois blocos amostrais de 0,99 ha cada no Parque Estadual Intervales. Todos os indivíduos com DAP > 5 cm foram registrados. Foram amostrados 3.078 indivíduos distribuídos em 172 espécies. O índice de diversidade de Shannon foi de H' = 3,85 nat.ind.-1. A família Myrtaceae se destacou tanto em número de espécies (38) quanto em número de indivíduos (745) no levantamento. Euterpe edulis Mart. teve o maior valor de importância (33,98%), abrangendo 21,8% do total de indivíduos registrados. O índice de similaridade quantitativo foi maior do que o qualitativo, mostrando pouca variação estrutural entre os blocos amostrais, mas a grande quantidade de espécies pouco abundantes, resultou em pronunciadas diferenças florísticas entre eles. Uma análise de correspondência retificada (DCA) gerou três estratos verticais arbitrários. O estrato A (> 26 m) teve a menor densidade e foi bem representado pelas espécies Sloanea guianensis (Aubl.) Benth. e Virola bicuhyba (Schott. ex A.DC.) Warb. O estrato B (8 m < h < 26 m) mostrou a maior riqueza e diversidade florística, e o estrato C (< 8 m) a maior densidade. Euterpe edulis, Guapira opposita (Vell.) Reitz, Garcinia gardneriana (Planch. & Triana) Zappi e Eugenia mosenii (Kausel) Sobral foram bem representadas nos estratos B e C da floresta. A existência de estratos verticais em florestas tropicais é discutida, recomendando-se o uso da DCA para estudos da estratificação vertical em outras florestas tropicais.

Feather mites of Brazil (Acari: Astigmata: Analgoidea and Pterolichoidea)

We present a checklist of feather mites known from native birds in Brazil. The list was compiled from a survey of Brazilian records published in indexing databases (e.g. Zoological Records) and from the available literature. To date, 185 nominal species representing 21 families have been recorded from Brazilian birds. Associations with 15 bird orders were found: Anseriformes, Apodiformes, Caprimulgiformes, Ciconiiformes, Columbiformes, Cuculiformes, Falconiformes, Galliformes, Gruiformes, Opisthocomiformes, Passeriformes, Piciformes, Psittaciformes, Tinamiformes and Trogoniformes. These birds sum to 218 species, which represent only 12.4% of all bird species occurring in Brazil. The feather mite fauna of several species-rich and important bird orders in Brazil remain unexplored, including Cathartiformes, Charadriiformes, Coraciiformes, Galbuliformes and Strigiformes. We estimate that between 900 and 5300 feather mite species are expected to occur on Brazilian birds, which is at least five times greater than current records. The training of researchers with expertise in the taxonomy of this group of mites should be stimulated so that there is a compatible number of taxonomists to discover and describe the almost unexplored feather mite fauna in Brazil.

Fish community structure along a conservation gradient in Bodoquena Plateau streams, central West of Brazil.

Aim: To investigate whether composition and structure of stream ichthyofauna vary along the conservation gradient in the Bodoquena Plateau; Methods: Standardized sampling was performed in nine stream stretches (three references, three in the pasture, and three in urban areas), each 80 m long, in April, May and June/08; Results: A quantity of 8,102 individuals representing 36 species was collected. There were no significant differences with respect to absolute species richness among stretches. Urban stretches were more similar to each other than the other two groups, both regarding species composition and abundance. A set of six species was considered an indicator of reference stretches, whereas two were of pasture stretches and four of urban stretches. Poecilia reticulata and Corydoras aeneus, occurring only in urban stretches, were unique in showing the maximum values in the indicator species analysis; Conclusions: Results indicate changes in the ichthyofauna with urbanized surrounding water courses. The presence and abundance of Poecilia reticulata and Corydoras aeneus may indicate the quality loss of these environments.

Community structure of aquatic insects (Ephemeroptera, Plecoptera, and Trichoptera) in Cerrado streams of Paraguay, Paraná, and São Francisco river basins

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Temporary fragmentation of a marginal lake and its effects on zooplankton community structure and organization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Environmental factors predicting fish community structure in two neotropical rivers in Brazil

Com o objetivo de identificar os padrões de organização das comunidades de peixes dos rios Jogui e Iguatemi nós amostramos peixes através de redes de espera trimestralmente entre Novembro/1999 e Agosto/2000. Hypostomus ancistroides e Parauchenipterus galeatus foram as espécies de peixes mais abundantes nos rios Jogui e Iguatemi, respectivamente. A variação longitudinal foi mais importante que a sazonal na determinação da composição de espécies em ambos os rios e a diferença entre estações não foi significativa. A altitude foi o fator mais importante na determinação da distribuição das espécies.

Community structure and comparative analysis of the woody component of a cerrado remnant in Southeastern Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Foraging, diet and community structure in an epigaeic ant (Hymenoptera: Formicidae) assemblage: the role of recruitment

The significance of recruitment systems for community structure of epigaeic ants in a tropical upland forest in southern Brazil was evaluated by examining patterns of spatial occurrence at fixed points. Normal exploratory activity was evaluated with pitfall traps, while the effect of recruitment and diet was evaluated by using honey and sardine baits at the same points. Through techniques developed for environmental impact assessment, the significance of recruitment was evaluated following perturbation, or the placement of bait. Of the 46 species encountered, 15 were sufficiently frequent to study. Of these, only 6 showed significant spatial frequency changes at baits when compared with pitfall trap collections. In one analysis, monthly differences were important for a few smaller species, suggesting thermic limitations, while bait types either increased or decreased spatial point usage. The magnitude of spatial point variation is an index for the strength of recruitment in community organization. Bait types suggest nutritional possibilities of each species. Both recruitment and diet are probably functions of the species composition of the ant community.

A systematic review of feather mites of the pterodectes generic complex (acari: Proctophyllodidae: Pterodectinae) with redescriptions of species described by vladimír cerný

Five species of feather mites originally described in the genus Pterodectes by Vladimir černý (1974) are redescribed: Pterodectes havliki, P. maculatus , P. reticulatus, P. storkani, P. thraupicola and P. troglodytis. The formerly unknown males of P. thraupicola and P. reticulatus and the female of P. maculatus are described for the first time. A synopsis of known species of the Pterodectes generic complex is presented, and species content of the genus Pterodectes is revised. Fifteen species previously included in this genus are transferred to the new genus Amerodectes gen. n.: Amerodectes atyeoi (OConnor et al., 2005) comb. n., A. bilineatus (Berla, 1958) comb. n., A. geothlypis (Berla, 1973) comb. n., A. gracilis (Trouessart, 1885) comb. n., A. maculatus comb. n., A. molothrus (Mironov, 2008) comb. n., A. nordestensis (Berla, 1958) comb. n., A. paroariae (Mironov, 2008) comb. n., A. pitangi (Mironov, 2008) comb. n., A. tangarae (Mironov, 2008) comb. n., A. turdinus (Berla, 1959) comb. n., A. sialiarum (Stoll, 1893) comb. n., A. storkani (černý, 1974) comb. n., A. thraupicola (cčerný, 1974) comb. n., and A. troglodytis (černý, 1974) comb. n. Five species are transferred to the genus Tyrannidectes Mironov, 2008: Tyrannidectes amaurochalinus (Hernandes et Valim, 2006) comb. n., T. banksi (Valim et Hernandes, 2008) comb. n., T. crassus (Trouessart, 1885) comb. n., T. fissuratus (Hernandes et Valim, 2005) comb. n., and T. reticulatus (Cerný, 1974) comb. n.; and one species is moved to the genus Metapterodectes Mironov, 2008: Metapterodectes muticus (Banks, 1909) comb. n. The genus Pterodectes remains monotypic, with the type species P. rutilus Robin, 1877. © Acarina 2010.

Relation between green spaces and bird community structure in an urban area in Southeast Brazil

Increased urbanization typically leads to an increase in abundance of a few species and a reduction in bird species richness. Understanding the structure of biotic communities in urban areas will allow us to propose management techniques and to decrease conflicts between wild species and human beings. The objective of this study was to describe the structure of the bird community in an urban ecosystem. The study was carried out in the city of Taubaté in southeastern Brazil. Point-counts were established in areas with different levels of tree density ranging from urban green spaces to predominantly built-up areas. We looked for a correlation between the richness/abundance of birds and the size of the area surveyed, the number of houses, the number of tree species and the number of individual trees. The results of multiple regression showed that bird richness had a direct relationship with vegetation complexity. The abundance and diversity of tree species were better predictors of bird species than the number of houses and size of the area surveyed. We discuss implications of this study for conservation and management of bird diversity in urban areas, such as the need to increase green areas containing a large diversity of native plant species. © 2011 Springer Science+Business Media, LLC.