PARENT OFFSPRING CONFLICT RELATIVE TO PHASE OF LACTATION

Weaning conflict in captive collared peccaries, Tayassu tajacu, was examined to test whether the highest proximate conflict occurs near the termination of lactation or near the mid-lactational decline in milk production. Since the frequency of conflict behaviour might be related to the condition of the nursing female, the subjects were placed on two dietary treatments corresponding to protein availability typical of conditions of drought (7·5%) and high rainfall (16·5%). Data were analysed within three developmental phases: milk dependency (1-7 weeks), transition (7-15 weeks) and terminal (15-36 weeks). Nursing females did not take an active role in interrupting nursing bouts; in all but one phase (transition phase on low protein diet), nursing females interrupted less than half the suckling bouts. Three of four measures of conflict did not differ relative to phase of lactation analysed within diets. On the low protein diet, juveniles persisted at initiating unsuccessful attempts more frequently in the third phase. Within each phase, measures of conflict were more frequent on the low protein diet than on the high protein diet. Juvenile persistence was a more sensitive indicator of conflict than nurser interruptions. Nutritional condition appears to be an important factor modifying the expression of parent-offspring conflict. © 1990 The Association for the Study of Animal Behaviour.