Juvenile dispersal in Calomys venustus (Murida : Sigmodontinae)

摘要

Both spacing behaviour and dispersal movement are viewed as hierarchical processes in which the effects may be expressed at spatial scale. This research was carried out to examine the hypothesis that the presence of parents promotes the dispersal of juveniles from their natal nest and their father or mother home-range, in Calomys venustus. The study was carried out in four 0.25 ha fences (two controls and two experimentals), in a natural pasture. This study had two periods: Father Removal (FR) (August and December 1997; year one) and Mother Removal (MR) (August 1998 and January 1999; year two). For the FR treatment fathers were removed after juveniles were born, but in the MR treatment mothers were removed after the juveniles were weaned. The effect of parents on the dispersal distance of juveniles was analysed with respect to their natal nest and their mother and father home-range. Dispersal distance from the nest of C. ventistus was independent of either male or female parent. Juveniles were more dispersing in relation to the centre of activity of their mothers than to that of their fathers, and females were more dispersing than males. Female juveniles overlap their home-range with their parents less than male juveniles do. The differences observed between female and male juveniles would be related to their different sexual maturation times, as well as to the female territoriality. (C) 2004 Elsevier SAS. All rights reserved.