Growth and home range size of the gracile mouse opossum Gracilinanus microtarsus (Marsupialia: Didelphidae) in Brazilian cerrado

Abstract

Differences in growth patterns between the sexes of the gracile mouse opossum Gracilinanus microtarsus and the consequences for home range size were investigated in a savanna habitat (cerrado) of south-eastern Brazil. A total of 51 juvenile individuals of Gracilinanus microtarsus was monitored using capture-mark-recapture from November 2005 to August 2006. The increase in body mass of gracile mouse opossums was described using the Gompertz growth model. Male gracile mouse opossums grew faster than females (dimorphic ratio of 1.5). Home range size, estimated with the minimum convex polygon method, was positively related to body mass. Model selection using Akaike's Information Criterion (AIC c ) and incorporating body mass, sex and season as independent variables showed that the best-supported model describing variance in home range sizes included only body mass. Our data suggest that a greater body mass gain in juvenile males is probably the proximate cause of sexual dimorphism in adult gracile mouse opossums and that energetic needs required for growth have a greater influence in home range size.

Spatial patterns of the semi-aquatic rodentNectomys squamipesin Atlantic forest streams

“…A similar pattern was also documented for the HRs of several mammals (Harestad and Bunnel 1979;Mace and Harvey 1983;Fernandes et al 2010;Oliveira et al 2012). As bigger animals demand more resources, they need to explore larger areas to find them (Harestad and Bunnel 1979).…”

Effect of body size on the abundance of ectoparasitic mites on the wild rodent Oligoryzomys nigripes

“…This intersexual difference in physiology is based on the negative relationship between the male hormone, testosterone, and immune function, making males more susceptible to the majority of parasite infections (Klein 2004). Behavioral differences between genders are related to the greater mobility of males in systems with promiscuous mating, as the range of a female is generally associated with habitat quality, while the range of a male is associated with an improved probability of finding sexual partners (Püttker et al 2006;Fernandes et al 2010;Perdue et al 2011).…”

Modelling Animal Activity as Curves: An Approach Using Wavelet-Based Functional Data Analysis

“…On the other hand, survival rate in males decreases sharply in the post-mating period and is significantly lower than that of females [41]. The decrease in survival rate in males is probably explained by than that in females (0.12 ± 0.09 ha [48]). …”

“…Body size has a positive, linear association with the area traversed by an individual in its normal activities of food gathering, mating and caring for the young [45] [46] [47]. As expected, the area traversed in nature is larger and more variable in male than in female gracile opossum [48]. Therefore, we expect that activity patterns will differ between male and female gracile opossum.…”