The focus of this work was to survey the ichthyofauna of the Penacho stream, a tributary of the Laranjinha River, northeastern Paraná State, in an area of the Upper Paraná River basin still devoid of ichthyofaunal studies. In general, the banks of the Penacho Stream are predominantly characterized by pasture or agricultural activities and may exhibit little riparian vegetation in few stretches. Fishes were collected at eight different locations, from its headwaters to its mouth, between February 2009 to March 2010. A total of seven orders, twelve families and thirty-three species, three of which not native to the basin, were reported. The fish species captured along the Penacho stream are those that still manage to stay in those environments, even in changed conditions. However, to better understand the effects of degradation on fish diversity, it is necessary to monitor it along time.

Over the past few decades, South American Rivers, including the Paraná River system, have been intensely impacted by dam constructions. To mitigate adverse impacts, fish passages were incorporated into two large dams on the Paraná River (Itaipu and Porto Primavera) to reestablish longitudinal connectivity, which is very important for conserving populations of migratory fish species. The aim of this study was to estimate genetic diversity, population differentiation and gene flow, using microsatellites markers and mitochondrial haplotypes (D-loop), in populations of Prochilodus lineatus, a long distance migratory species commonly found in Paraná River basin drainages. Samples were obtained from six locations in the Upper and Middle Paraná River: Porto Primavera Reservoir, downstream of the Porto Primavera Reservoir, four tributaries of this reservoir (Pardo, Peixe, Verde and Aguapeí Rivers) and in the Iguaçu River, downstream of the Itaipu dam. High genetic diversity was observed in all samples, as expected for species with large population sizes and high migration rates. However, the influence of other factors, such as secondary contacts, fish passages and restocking were also suggested. In general, evidence of spatial population structuring was not found, even though there were two large dams in the study area. This could also be attributed to the brief period that has elapsed since the dams were built, the influence of migratory and reproductive patterns and the possible contributory effects of the fish passages. Furthermore, the absence of population structuring also corroborates existing information that emphasizes the importance of unimpeded tributaries for conserving migratory fish populations in fragmented watersheds.

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The Neotropical brown stink bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae), is a major Brazilian soybean pest. Aiming to provide relevant information to implement pest and insecticide resistance management, new microsatellite loci were developed for E. heros and used in a study of genetic diversity and population structure. The population analysis was performed using eight microsatellite loci from 17 samples (n = 243 individuals) collected in the major soybean‐producing regions in Brazil (northeastern, midwestern, and southern regions). These microsatellite loci provided high genetic diversity values on the whole extension for the studied region (He = 0.895; total number of alleles = 400). Neotropical brown stink bug populations in general displayed low genetic structure levels among the samples (overall ΦST = 0.009). An exception was the sample from the northeastern region, which showed a significant genetic differentiation (pairwise ΦST = 0.031–0.063). Bayesian cluster analysis confirmed these results, did not show population subdivision, and indicated considerable levels of gene flow. Significant correlations between genetic differences and geographic distance were obtained. The lowest estimate of migration was found in the population from São Desidério, which was also the most distant from the remaining populations based on genetic distance. Some plausible hypotheses for the low genetic differentiation among these populations are the fast expansion of soybean production areas, the main food source of E. heros, polyvoltinism, and possible influence of anthropogenic dispersal. All these factors could have led to high population densities, a wide distribution that may contribute to reduced population differentiation, and increased genetic diversity.

-The incidence of diploid males among 1457 individuals of different populations of six euglossine bee species (Eufriesea violacea , Eulaema cingulata , Euglossa annectans , Euglossa iopoecila , Euglossa pleosticta and Euglossa truncata ) was investigated with microsatellite markers. Bees were surveyed in Atlantic Forest fragments showing different sizes and degrees of human interference. Our analyses revealed that, although the frequencies of diploid males remained below 10 % for five out of six species studied, the frequencies of these males in three populations of Eg. annectans were above 15.0 %. For this species, while the average estimate of diploid males was around 11.0 %, the highest percentage (27 %) of such males was found for the population from an island. Our findings indicate that the frequency of diploid males can vary substantially among species and this fact should be taking into consideration in studies and conservation actions involving different euglossine bees. microsatellites / Euglossini / euglossine bees / Euglossa annectans / forest fragments

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Specimens of Pimelodellacaptured in the Miranda River, Pantanal of Mato Grosso do Sul State, present morphological features that could indicate at least four species. Therefore, karyotype analysis and molecular biology provided evidence that they were only two species, one showing 2n = 46, and the other, 2n = 52 chromosomes, with only 18% genetic similarity. The morphological analysis evidenced that the dorsal filament is a male characteristic and that the upper lobe of the caudal fin was variable and might or might not be elongated in both species. With respect to morphometric characters, the formation of two groups was evident, but with a small overlap of specimens between them. Among the species with filaments on the dorsal fin observed in the Pantanal, the one with the lesser length of adipose fin base is P. griffini, which corresponds to that with 2n = 46 chromosomes, whereas the species P. taenioptera has 2n = 52 chromosomes. Thus, the accurate detection of these cryptic taxonomic units was only possible with the use of various analysis techniques. Furthermore, it is worth noting that the identification of cryptic species is important for obtaining correct estimates of fish diversity in the Pantanal