Taxonomic revision of the Neotropical genus Heteragrion Selys, 1862 (Zygoptera: Heteragrionidae): male morphology, new species and illustrated key

In this study, we have comprehensively presented taxonomic information on all 62 known species of Heteragrion Selys, 1862, which includes illustrations, photographs, diagnostic characters, and a key to males. Our analysis is based on the examination of over 900 specimens from 19 different collections worldwide, encompassing the type material for at least 42 species. Furthermore, we have described a new species, Heteragrion corderoi sp. nov. (, BRAZIL, So Paulo state, Campos do Jordo, Condomnio Paradise, 24.i.1999, (Coordinates: -22.7072, -45.5894, 1796 m asl), F.A.A. Lencioni leg., LABECO), which we identified from a male that was previously considered to be a paratype of H. mantiqueirae Machado, 2006 and additional specimens collected in Campos do Jordo, So Paulo state.

Allometry for Sexual Size Dimorphism in Stoneflies Defies the Rensch's Rule

The Rensch's rule predicts that male-biased sexual size dimorphism (SSD) increases with body size, while female-biased SSD (FBSSD) decreases. In insects, many groups follow this rule, but the evidence suggests that it is taxon dependent and that the inverse of the rule can occur in species with FBSSD. Therefore, we conducted this study with Gripopterygidae stoneflies (Plecoptera) to describe their pattern of SSD and determine if they follow the Rensch's rule. Our data suggest that stoneflies exhibit FBSSD and do not follow the rule, but a reverse pattern. Our results corroborate other studies that suggest that the Rensch's rule is taxon based and that groups with FBSSD usually fail to obey the rule.

Fluctuations in richness and abundance of social wasps during the dry and wet seasons in three phyto-physiognomies at the tropical dry forest of Brazil

The social wasp nests were quantified in three different plant physiognomies (forested Caatinga, shrubby Caatinga, and agricultural systems) to analyze the effect of environmental seasonality and plant physiognomy on the richness, nest abundance, and species composition of social wasps in the region of tropical dry forest of Brazil. The forested Caatinga physiognomy had the greatest richness of species (S = 16), followed by shrubby Caatinga (S = 13) and by agricultural system (S = 12). The first axis of detrended correspondence analysis (DCA) explained 67.8% of the variability and shows a gradient of the fauna from agricultural system and shrubby Caatinga to forested Caatinga. In the first axis, wet season scores were much higher than those for the dry season in forested Caatinga. The second axis explained 18.7% of the variability and shows a separation of samples collected during the wet or the dry periods in shrubby Caatinga. This separation was less evident in the agricultural system. Variations in nest abundance were more intense in arbustive caatinga (45% decrease in number of active nests in the dry period), moderate in forested Caatinga (24% decrease in number of active nests in the dry period), and low in agricultural systems (8% decrease in the dry period).

Bee communities (Hymenoptera: Anthophila) of the "Cerrado" ecosystem in São Paulo State, Brazil

Five surveys of the bee communities in four "Cerrado" ecosystem reserves in São Paulo State were compared for species richness and similarity. These areas are fragment vegetation reser-ves located in the Cerrado Corumbataí Reserve (Corumbataí), Jataí Ecological Park (Luiz Antônio), Cajuru (Cajuru), and Vassununga State Park - "Gleba de Cerrado de Pé-de-Gigante" (Santa Rita do Passa Quatro). The methodology consisted of capturing bees foraging on flowers along transects, though with small differences between surveys. These "cerrado" areas have a large number of species of native bees, which are important pollinators in several Brazilian ecosystems. The community of bees varied among these different fragments. Based on 500 individuals (standardized by rarefaction), Cajuru, Corumbataí 1 and Corumbataí 2 were the areas with highest species richness, and Jataí and Pé-de-Gigante had the lowest species richness in the bee communities. The bee faunas of Corumbataí 2 and Pé-de-Gigante had the highest similarity, forming a group with the bee fauna of Cajuru. The bee faunas of Corumbataí 1 and Jataí were isolated from this group. We found that the bee species richness and similarity found in these "cerrado" areas cannot be explained by general factors such as the size of the fragment, the species richness of plants and the distance between the areas. Therefore, we suppose that local factors that differ among areas, such as interactions between populations, and competition and interference from surrounding areas influence and determine bee species richness and similarity in these reserves.

Ephemeroptera, Plecoptera and Trichoptera assemblages from riffles in mountain streams of Central Brazil: environmental factors influencing the distribution and abundance of immatures

The influence of environmental factors on the distribution of Ephemeroptera, Plecoptera and Trichoptera (EPT) immatures was investigated in streams of the Brazilian Center-West (Serra do Pireneus, Pirenópolis, State of Goiás). The insects were sampled by lifting the stones in front of a sieve (0.5 mm mesh) and then removing the insects from both the stone and the sieve. Sampling was carried out for 1 h at 5 collection sites over a period of 14 months. Air and water temperature (degrees C), water velocity (m/s), discharge (m(3)/s), electric conductivity (microS/cm), pH, and rainfall (mm) were also recorded. In general, we may state that altitude, hydrologic classification (order) and vegetation cover were the most important factors explaining the distribution of Ephemeroptera, Plecoptera and Trichoptera immatures. The influence of the rainfall on the temporal variation of the abundance of insects was stronger in stream segments of medium order (3rd, 4th order) compared to smaller streams (first order).

Spatial distribution of Plecoptera nymphs in streams of a mountainous area of Central Brazil

In this paper the spatial distribution of Plecoptera nymphs in the Almas' River basin, Pirenópolis, GO, was studied. Two Surber samples, each comprising 20 sampling units and totalling 2 m2, were taken in each of the 13 stations, one during the rainy season (January 1994) and the second during the dry season (July 1994). In 5 of these stations, monthly samplings were made from June 1993 to July 1994; in these, temperature, velocity, discharge, electrical conductivity and pH were measured. Regional rainfall was also obtained. To ascertain the distribution of nymphs in the habitat, a separate sample was taken. Of the factors considered, the most important affecting the spatial distribution of the stonefly nymphs were altitude, stream order, and anthropic influence. Locally, the genera Anacroneuria and Kempnyia showed clumped distributions, but the data for Gripopteryx and Tupiperla were inconclusive due to low numbers.