Comparative analysis of life-history traits in two species of C alomys (Rodentia: Sigmodontinae) in captivity / Analyse comparative des traits d'histoire de vie de deux espèces de Calomys (Rodentia: Sigmodontinae) en captivité
AbstractWe analyzed life-history traits (fertility, growth and rate of postnatal development) in captive-bred colonies of two closely related sympatric species: Calomys expulsus and C. tener (Rodentia, Sigmodontinae). We found significant differences between the species in growth rate and several reproductive traits. C. tener had a smaller litter size and litter mass, smaller proportion of litter mass to maternal mass, lower growth rate and higher infant mortality. We also found an apparent difference in correlation patterns of life history parameters between the two species of Calomys . The strong correlation between body size and fecundity found in other studies of life history traits and in selection experiments seems to be disrupted in C. tener . We found a significant positive correlation between maternal mass and litter size and mass only for C. expulsus, which means that in C. tener the fertility of females does not depend strongly on body mass. We discuss inbreeding depression and stress reactions as possible reasons for these results.