Marta E. Fabián

Hábitos alimentares e uso de abrigos por Chrotopterus auritus (Chiroptera, Phyllostomidae)

Chrotopterus auritus (Peters, 1856) (Phyllostomidae, Chiroptera) é a única espécie carnívora de morcego registrada para o estado do Rio Grande do Sul. Neste trabalho a dieta e o uso de abrigos diurnos foram estudados. Sete cavernas foram monitoradas, a cada quinze dias, no período de maio/2002 a abril/2003, nos municípios de Machadinho e Barracão, Rio Grande do Sul, Brasil. A dieta foi estudada por meio da análise das fezes (n = 67) e restos alimentares (n = 63) coletados quinzenalmente em cada abrigo. Mamíferos, aves e artrópodes constituíram a base alimentar de C. auritus. O resultado do exame das fezes não evidencia a preferência por presas como mamíferos, aves ou artrópodes, pois não há diferença significativa na freqüência de ocorrência dos mesmos. O mesmo resultado foi obtido na comparação dos itens alimentares constantes nas fezes entre as estações do ano. Dentre os mamíferos consumidos predominaram os roedores; dentre as aves, os passeriformes e dentre os artrópodes, os coleópteros. Frutos foram consumidos em menor freqüência, cerca de 5,9% do total das amostras. C. auritus esteve presente durante todo o período de estudo em cavernas, variando em número de indivíduos e abrigos ocupados. Observou-se coabitação com Desmodus rotundus e Myotis nigricans.

Food habits and use of roosts by Chrotopterus auritus (Chiroptera, Phyllostomidae). Chrotopterus auritus (Peters, 1856) (Phyllostomidae, Chiroptera) is the only species of carnivorous bat recorded in Rio Grande do Sul State. In this work we identified the diet items and observed their spatial distribution within roosting sites at daytime. We monitored seven caves, every fifteen days, from May 2002 to April 2003, in Machadinho and Barracão Counties, Rio Grande do Sul State, Brazil. The diet was inferred from fecal samples (n = 67) and food remains (n = 63). Mammals, birds and arthropods, composed the diet of the C. auritus. C. auritus did not show preference by food items, such as mammals, birds or arthropods, because there were no significant differences among them in fecal samples. The result was similar when comparing the presence of these items between seasons. Rodents, Passeriformes and coleopterans were the prevailing items in the diet of the C. auritus. Fruits were consumed occasionally, about 5.9% of the total of the samples. C. auritus was, during the whole study period, present in the studied caves, varying in number of individuals and shelters. Cohabitation with Desmodus rotundus and Myotis nigricans was observed.

Biologia reprodutiva de Delomys dorsalis (Hensel, 1872) —Rodentia, Sigmodontinae— em área de floresta ombrófila mista, Rio Grande do Sul, Brasil

Cristina Vargas Cademartori, Marta E. Fabián, João O. Manegheti

Reproductive biology of Delomys dorsalis (Hensel, 1872)—Rodentia, Sigmodontinae—in an area of mixed forest with conifers, at Rio Grande do Sul, Brasil. Delomys dorsalis is restricted to the wet tropical and subtropical forests of southern and southeastern Brazil and northeastern Argentina. The reproductive cycle of this species was studied by the histological examination of the reproductive tracts of animals caught in an area of mixed forest with conifers (29° 23′ S, 50° 23′ W), in southern Brazil, and from observations on a laboratory group of individuals. Fourteen expeditions were carried out from February 1997 to April 1998, during approximately 3 nights, using 140 live traps set on the ground and on branches between 1.5 and 2.0 m high. Reproductively active individuals were observed year round, although winter was marked by a reduction in breeding activity resulting from recruitment. Females showed a post-partum oestrus and a gestation time between 21 and 22 days. The litter size in captivity ranged from two to four, though pregnant females collected from the field had even five embryos. External reproductive features, frequently used as indicatives of the reproductive status of small mammals in ecological studies, were not accurate and underestimated the number of active animals in the population. Some individuals showed a remarkable scansorial ability that should be considered in future studies about population dynamics.