Microcrustaceans in rice fields: A scientometric analysis from 1977 to 2019.

We evaluated the worldwide trends in studies of the active and dormant forms of microcrustaceans in rice fields, and the potential of this environment as a stock of diversity through a scientometric analysis. Web of Science and Scopus databases were used to compile the 77 studies published before 2019. Publications were distributed over 35 years, with a positive correlation between the number of studies and the year of publication (rho = 0.34). The identified studies were from 18 countries, and 58.4% were conducted in Japan, Italy, the United States, and Spain. Most studies addressed more than two groups of microcrustaceans (37.6%), followed by those focused on Cladocera (27.2%) and Ostracoda (18.1%). We quantified 301 species from six groups of microcrustaceans, the majority of which were Cladocera (41.5%) and Ostracoda (39.8%). The greatest richness of microcrustaceans identified in studies were found in Italy, Thailand, Malaysia, Spain, France, Japan, and Brazil. Of the studies, 87% were centered on the active forms of microcrustaceans rather than dormant forms. We found that 15.5% of the countries that grow rice have identified the richness of microcrustaceans, and even though they are artificial environments, rice fields have high potential to store a high diversity of microcrustaceans.

Cladocera (Crustacea, Branchiopoda) in coastal temporary environments in southern Brazil.

The coastal plain of Rio Grande do Sul state, southern Brazil, presents as characteristic large expanses of wetlands. Some of these environments are of a temporary nature, and thus have a community adapted to periods with water and periods of drought. Among these communities we can highlight the Cladocera, which have the capacity to form structures of dormancy, and due to this adaptation are effective at colonizing these environments. This study aims to identify the Cladocera species present in the temporary aquatic environments of the southern coastal region of Brazil. Samples were collected in 14 temporary aquatic environments using a classical filtering methodology. As results we obtained 64 Cladocera taxa, representing 54% of the total number of species described in Brazil. The number of taxa was high, the species accumulation curve showed a tendency to stabilization, demonstrating that this region possesses a greater richness.

Natural diet of three species of shrimp in a tropical coastal lagoon

The gut content of 495 specimens of Farfantepenaeus brasiliensis, 131 of F. paulensis (Penaeidae) and 102 of Macrobrachium acanthurus (Palaemonidae) were analyzed to establish the composition of their diets F. brasiliensis had as the most important feeding items in its diet larvae of Chironomidae, Polychaeta and Heleobia australis (Mollusca). For F. paulensis, the most important items were the same as for F. brasiliensis, but the order of importance of H. australis and Polychaeta was inverted. M. acanthurus had detritus as the most important item, followed by Chironomidae larvae, Odonata nymphs, and fragments of the macroalgae Chara. The results showed that the three species were omnivorous, with a varied diet including both components of macrofauna of benthos and associated to the macroalgae Chara and plant fragments and detritus