The aim of this study was to characterize the reproductive strategies of a population of Hyalella bonariensis from southern Brazil. Pairing success, reproductive period of males and females, fecundity, and body size at the onset of reproduction were evaluated. Animals were sampled four times (August 2012, October 2012, January 2013, and April 2013) with the 250 µm-mesh dip net during 20 minutes by only one person. In the field, precopulatory pairs and ovigerous females were individualized. In the laboratory, cephalothorax length (CL) were measured and eggs and juveniles were removed from the females' marsupium and counted. The mean CL of paired males and females was significantly higher than that of non-paired males and females. A sexual dimorphism in body size was observed in the population - both paired and non-paired males were larger than females. Probably larger males have a higher probability of losing females during precopulatory behavior. A significant correlation was observed between the size of paired males and females - larger males often paired with larger females and smaller males paired with smaller females (r = 0.81). The pairing success of males increased with body size and we can assume that males from all size classes are able to find mates. The pairing success of females was independent of body size - paired and non-paired females had similar mean CL. The reproductive success increased with body size in males and females, and was more evident in males. Females from the largest size classes had null reproductive success. The idea that larger females can produce more eggs but might have a lower probability of finding a mate than smaller females was corroborated by our results. Therefore, smaller females have higher pairing success because they are capable of mating with a higher percentage of males. The estimated mean fecundity of H. bonariensis was 17.4 (± 3.89) eggs/juveniles. Our results are similar to those of other species of Hyalella from Brazil.

There are 68 known species of Hyalella worldwide, with 23 occurring in Brazil. The state of Rio Grande do Sul, Southern Brazil, has the largest diversity of the genus in the country, with nine species recorded. The current study aimed to describe two new species of Hyalella from state of Rio Grande do Sul, both of them in the Northwest region of the state, one found in a small spring and another in an artificial pond. Hyalella georginae n. sp. presents several clusters of simple setae on antenna 2, maxilliped very slender, gnathopod 2 dactylus not reaching the lobe of propodus, pleopods rami with short plumose setae and a peculiar pattern of setae on uropods and telson. Hyalella gauchensis n. sp. presents antenna 2 with few setae, maxilliped very slender, gnathopod 2 dactylus reaching the lobe of propodus and pleopods rami with long plumose setae. From this work, the number of Hyalella species found in Brazil increases to 25 and 70 for the genus.

Áreas de Preservação Permanente (APPs) e Reserva Legal (RL) são áreas protegidas pelo Código Florestal Brasileiro que exercem importante papel na preservação ambiental. Foram realizadas atividades de conscientização ambiental nos Assentamentos Potreiro Bonito e Terra Nova, localizados no Município de Palmeira das Missões-RS, visando a promover e ampliar a troca de conhecimento sobre APPs e RLs e incentivar a conservação e recuperação destas áreas. A mobilização dos assentados para a participação nas atividades foi realizada com o auxílio da EMATER-Palmeira das Missões e as atividades constaram de palestras, questionamentos, troca de experiências e distribuição de mudas de árvores. Observou-se que os produtores reconhecem a importância da preservação das APPs e RLs, entretanto, não se sentem motivados a conservar tais áreas, por perceberem as áreas protegidas como áreas economicamente inativas. Essa dissonância entre o reconhecimento da importância da preservação das APPs na teoria, e a preocupação da perda de área agriculturável na prática evidencia a importância do investimento contínuo em educação ambiental, principalmente através de projetos e programas de longo prazo, para despertar o interesse dos assentados em participar diretamente de um processo produtivo em harmonia com o meio ambiente.