A two-year mark-recapture study of small mammals was conducted in an area of Atlantic Forest hillside in the state of Santa Catarina, Brazil. Four species of marsupial and seven species of rodent were captured during 12 132 trap-nights. Aspects of population dynamics and natural history are discussed for each common species. The sex ratio was biased toward males for all species. Oryzomys russatus, Didelphis aurita and Akodon montensis had the highest population densities, the least amount of variation in population density and an inverse relationship between survivorship rates and population densities. Micoureus paraguayanus, Nectomys squamipes and O. angouya, registered the higher population densities after continual survivorship rates. The recruitment rates were low for most species (< 50%), with some, M. paraguayanus, Lutreolina crassicaudata, Oligoryzomys nigripes, O. angouya and Oxymycterus aff. judex, disappearing occasionally from the study area. The survivorship rates were high for most species (> 50%). Population densities of D. aurita, O. nigripes and O. aff. judex increased in cold and dry periods. The marsupials reproduced seasonally from late winter until the end of the summer, whereas rodents reproduced throughout the year. No species were long-lived, with average life-span < six months.

Mesmo tendo sido desenvolvido um arcabouço teórico dos processos que estruturam as comunidades, existem poucos testes dos mecanismos que promovem a coexistência em comunidades locais. Neste trabalho é descrito um experimento de campo desenhado para determinar o papel da partilha de recursos como um mecanismo promotor da coexistência e do aumento da diversidade usando comunidade necrófagas como modelo. Para realizar este estudo foram deixadas no campo para que fossem colonizadas, 36 carcaças com peso variando entre 17 e 440 g em um experimento com três repetições. A comunidade é composta de 21 espécies de moscas necrófagas. As análises iniciais sugeriam partilha de recursos mas existe mais sobreposição do que é esperado ao acaso e o nível de especialização em relação ao tamanho da carcaça foi baixo. Assim, as evidências indicam que a partilha de recursos não pode ser o principal mecanismo promotor da coexistência, considerando o tamanho das carcaças utilizadas.

Even though an extensive framework has been develop on community structuring process, there have been few tests of mechanisms promoting coexistence in local communities.We report field experiments designed to assess the role of resource partitioning as a mechanism promoting coexistence and enhancing diversity using necrophagous communities as a model system. In order to achieve this objective we let in field to be colonize, 36 carcasses with weight ranging from 17 to 440 g, performing three repetitions. The community was composed by twenty one species of necrophagous flies. Initial analysis suggest some level of resource partitioning but there were more overlap than could be accounted by chance and the level of specialization on carcass size were very low. Based on this findings resource partitioning could not be promoting coexistence and another mechanism should be invoked to account for such effect.

Along ten years of study of a common dolphin from the brazilian coast, Sotalia brasiliensis Van Beneden, 1874, I could see some occasions of feeding associations of this dolphin with five species of birds, Sula leucogaster (Boddaert, 1783), Fregata magnificens Mathews, 1914, Sterna hirundinacea Lesson, 1831, Larus dominicanus Lichtenstein, 1823 and Phalacrocorax olivaceus Humboldt, 1895. The commonest association observed was between the dolphin and S. leucogaster, and in all the associations was characterized the commensalism, with advantaged to the birds.

A method for chronological age determination based on mesothoracic post-phragma post-emergence deposition of chitin is used for Chrysomya putoria and Phaenicia cuprina (Diptera, Calliphoridae). The age of these species were obtained by the maximum period of deposition which were of 11-12 days.