Revista Brasileira de Zoologia 24 (2): 283-293, junho 2007The structure of the fauna of aquatic insects in lotic environments is directly related to geomorphology, hydrology, quality of water, quality and availability of food resources, dominant substratum, temperature and dissolved oxygen (VANNOTE et al. 1980, RICHARDS et al. 1993, ZAMORA-MUÑOZ et al. 1993, ZAMORA-MUÑOZ & ALBA TERCEDOR 1996, BISPO et al. 2006. Those characteristics vary in time and space; therefore, it is expected that those variation determine the spatial and temporal alteration of diversity and of structure of fauna in the aquatic communities.Among the aquatic insects, Ephemeroptera, Plecoptera and Trichoptera, usually known as EPT, comprise a rich assemblage of taxa in low and medium order cobble streams. These organisms are sensitive to environmental perturbations and occur, mainly, in clean and well-oxygenated waters. Due to those characteristics, these organisms are frequently considered as good indicators of water quality (ROSENBERG & RESH 1993). According to MARCHANT et al. (1995), patterns found for EPT represent the same patterns found for the macroinvertebrate fauna as a whole; for this reason, studies could be restricted to that fauna. BISPO et al. (2006) have investigated the effect of environmental factors over the distribution of EPT and have concluded that precipitation, stream order and altitude were the main factors that determine distribution and fauna abundance. The present work aimed to evaluate the effect of spatial variation, including the effects of stream size, anthropic action, and seasonality (dry and rainy seasons) over diversity and structure of Ephemeroptera, Plecoptera and Trichoptera assemblages. Caixa Postal 131, Goiás, ABSTRACT. The diversity and structure of Ephemeroptera, Plecoptera and Trichoptera (EPT) assemblages in streams of Central Brazil (Serra dos Pireneus, Pirenópolis, State of Goiás) was investigated. Abundance data of EPT were obtained in Central-West Brazilian streams in order to evaluate the effect of spatial variability, including the effect of size of the stream and anthropic action, and seasonality (dry and rainy seasons) on faunal diversity and structure. The immatures were collected with circular sieves (0.5 mm mesh) during one hour at five collection stations over 14 months. From a spatial point of view, the data showed that anthropic action determined the patterns of diversity whereas the size of streams (1 st and 3 rd -4 th orders) determined the faunistic composition. In addition, environmental seasonality was an important factor for structuring the EPT fauna. Div

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Wing pigmentation is a trait that predicts the outcome of male contests in some damselflies. Thus, it is reasonable to suppose that males would have the ability to assess wing pigmentation and adjust investment in a fight according to the costs that the rival may potentially impose. Males of the damselfly Mnesarete pudica exhibit red-coloured wings and complex courtship behaviour and engage in striking male-male fights. In this study, we investigated male assessment behaviour during aerial contests. Theory suggests that the relationship between male resource-holding potential (RHP) and contest duration describes the kind of assessment adopted by males: self-assessment, opponent-only assessment or mutual assessment. A recent theory also suggests that weak and strong males exhibit variations in the assessment strategies adopted. We estimated male RHP through male body size and wing colouration (i.e. pigmentation, wing reflectance spectra and transmission spectra) and studied the relationship between male RHP and contest duration from video-documented behavioural observations of naturally occurring individual contests in the field. The results showed that males with more opaque wings and larger red spots were more likely to win contests. The relationships between RHP and contest durations partly supported the self-assessment and the mutual assessment models. We then experimentally augmented the pigmented area of the wings, in order to evaluate whether strong and weak males assess rivals' RHP through wing pigmentation. Our experimental manipulation, however, clearly demonstrated that strong males assess rivals' wing pigmentation. We finally suggest that there is a variation in the assessment strategy adopted by males.

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Universidade Federal da Integrac ßão Latino-Americana (UNILA), Parque Tecnol ogico Itaipu, Foz do Iguac ßu, Paran a, Brasil SUMMARY 1. Habitat complexity is thought to play an important role in various ecological communities, but its role under variable natural conditions is not well understood, particularly in lotic habitats where the complexity of the substratum influences the diversity and abundance of the benthic community. 2. We investigated the effects of the habitat complexity of the substratum, as represented by fractal structure, on the establishment of stream macroalgae. We also analysed the influence of hydraulic conditions associated with variations in the fractal dimension of the substratum. We hypothesised that habitats with higher surface complexity would have higher macroalgal abundance and that hydraulic conditions would affect macroalgal establishment differently on surfaces of differing complexity. 3. We designed a field experiment to elucidate the role of habitat complexity (represented by the fractal dimension and density of roughness elements) and consequent hydraulic conditions (assessed by the Reynolds number and drag forces) on algal growth. Sterile artificial substrata with five levels of complexity were placed in four unshaded streams. After 60 days of complete submergence, the substrata were removed from the streams, and the per cent cover of macroalgae was measured. 4. We used a principal components analysis (PCA) to reduce the dimensionality and collinearity among our variables (fractal dimension, density of roughness elements, Reynolds number and drag force) and summarise them adequately. Axis 1 (PC1) values were used in a linear model to assess the relationship between the variables and macroalgal cover. 5. PC1 explained 82.2% of the variability in substratum complexity and hydraulic condition. The fractal dimension and density of the roughness elements were negatively related with PC1, whereas the Reynolds number and drag force were related positively. Hydraulic conditions differed among each level of complexity, with the Reynolds number and drag force decreasing with increasing complexity. Macroalgal cover increased on surfaces with lower turbulence and drag force, indicating that less aggressive conditions are suitable for macroalgal colonisation. Additionally, the establishment of macroalgae was greatest on the leading edge of flat-top ridges, where the water velocity slows and the current changes direction. 6. Habitat complexity and hydraulic conditions play an important role in the establishment of macroalgae in streams and could explain their naturally patchy distribution.

-This study aimed at evaluating the effect of collect time (day and night) on ant fauna attracted to baits in areas of Eucalyptus cloeziana (Myrtaceae) and cerrado. The ants were collected in Fazenda Boa Vista, Mannesmann Fi -El Florestal Ltda, Paineiras, Minas Gerais State. Eigthteen sample units were collected: 12 in E. cloezina and six in cerrado. Each sample unit consisted of three plots (25 x 35 m each). The plot consisted of 34 baits distributed in a grid pattern at 5 m intervals. The sampling was carried out in the diurnal and nocturnal period. The results obtained revealed that both type of vegetation (cerrado x Eucalyptus) and the collect time (day x night) had a signifi cative infl uence on the epigaeic ant fauna. The ordination (DCA) indicated that collect time effect was more important to fauna structuration than the vegetation effect. (Finn et al. 1999). A variabilidade espacial tem sido levantada como um dos

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Specimens of Perlidae (Plecoptera) deposited in the Entomological Collection "Padre Jesus S. Moure" of the Universidade Federal do Paraná and additional material recently collected in Paraná and Santa Catarina states, Brazil were studied. Six previously described species were identified, Anacroneuria debilis (Pictet, 1841), A. cathia Froehlich, 2002, A. polita (Burmeister, 1839), A. trimacula Jewett, 1959, Kempnyia neotropica (Jacoson and Bianchi, 1905) and K. colossica (Navás, 1934). Additionally, a new species, Anacroneuria iguazu n. sp is described.