Tamanho corporal em populações naturais de Didelphis (Mammalia: Marsupialia) do Sul do Brasil

Abstract

Body size in natural populations of Didelphis (Mammalia:Marsupialia) from southern BrazilNowaday, data about marsupial biometry are poorly available in Brazil, considering the high richness of marsupial species in this country. Then, relationships of body size and sexual dimorfism of natural populations of the white-eared opossum, Didelphis albiventris, and of the common opossum, D. marsupialis, were studied in two mixed forests of Curitiba, southern Brazil, between February 1995 and February 1997. As a result, there was a strong relationship among the teeth emergence, weight and several body measures obtained from opossums. Hence, measures as the head length may be used to estimate other measures of the body. Sexual dimorfism was also verified in relation to the body size and the head shape for the common opossum. Adult females of the white-eared opossum proved to be bigger than adult females of the common opossum. Besides, some individuals of both species had an increase in their weight during the autumn probably to support the low food available' season. However, the white-eared opossum usually storages more fat that the common opossum in any season. Therefore, the adaptative strategies of both species revealed different among themselves in southern Brazil and probably are results of different life histories, despite their related kinship.Key words: opossums, biometry, growth, sexual dimorfism, fat index. RESUMO

Body size of commom opossum Didelphis aurita Wied-Neuwied 1826 (Didelphimorphia: Didelphidae) on southern brazilian islands

“…Some authors have reported no sexual dimorphism for Didelphis (Monteiro-Filho, 1987;Stallings, 1989), but it is common to find that at least some of the body measurements are larger in males than in females (e.g., Gardner, 1973;Tyndale-Biscoe and Mackenzie, 1976;Fonseca and Kierluff, 1989;Cherem et al, 1996;Catzeflis et al, 1997;Cáceres and Monteiro-Filho, 1999;Cerqueira and Lemos, 2000) as observed in this study. However, a variation in this pattern, such as the tail length of females from Arvoredo Island being longer than that of males, can occasionally occur.…”

“…They also play a major Nevertheless, biometric information on Didelphis is restricted to general studies (e.g., Gardner, 1973;Tyndale-Biscoe and Mackenzie, 1976;Fonseca and Kierluff, 1989;Catzeflis et al, 1997;Cerqueira and Lemos, 2000) with little data being available on insular species (Cherem et al, 1996) or comparisons between populations (Cáceres and Monteiro-Filho, 1999). Even so, the few studies which have compared body size among Didelphis populations have contributed to some ecological understanding of this genus (Cáceres and Monteiro-Filho, 1999).…”

Pequenos mamíferos não-voadores do Planalto Atlântico de São Paulo: identificação, história natural e ameaças

“…A dieta onívora é corroborada também pelo comprimento similar de todos os segmentos do trato digestivo (Caceres 2005). Pode ser considerada dispersora de sementes, importante na manutenção da regeneração da floresta (Caceres e Monteiro-Filho 2007), pois grande parte das sementes é viável após consumo (Caceres e Monteiro-Filho 1999).…”

“…: Caceres et al 2002, Grelle 2003, Almeida 2008) e em diversos fragmentos florestais (Caceres e Monteiro-Filho 1999, Barros 2006, Medina 2007, Guedes 2008, Pinto et al 2009), e no Rio de Janeiro como no Planalto de São Paulo, foi mais comum em fragmentos de mata do que em floresta contínua ). Apesar de ter sido raramente capturada em áreas abertas , movimenta-se entre fragmentos de mata através de áreas abertas (Pires e Fernandez 1999, Quental et al 2001, Goulart et al 2006), a distâncias de até 800 m (Pires et al 2002).…”

“…A dieta insetívora-onívora é corroborada por estudos de fezes que encontraram maior consumo de artrópodes (Caceres e Monteiro-Filho 1999), especialmente das ordens Coleoptera e Hymenoptera , Pinheiro et al 2002 , crustáceos (Pinheiro et al 2002) e fragmentos de flores .…”