Parental defence of an empty nest after catastrophic brood loss

We studied parental care behaviour in a field population of convict cichlids, Amatitlania siquia, a fish with biparental care of its free-swimming young (fry). We simulated catastrophic brood loss by removing all of the young from 26 broods of various ages. We recorded parental defence behaviour for 5 min preremoval and three consecutive 5 min postremoval intervals. We then returned all of the young and recorded 5 min of parent-offspring reunion behaviour. Following brood loss, both parents defended the empty territory and searched for missing young. Females spent more time in the empty territory and performed more attacks in defence of the empty territory than did males. Females searched and defended a significantly larger area than males did. During the 15 min fry-absent period, males increasingly spent more time away, whereas females maintained a constant level of investment in searching the brood area. Four of 26 males (15%) engaged in courtship with a new female within 15 min of brood loss. Attacks to repel potential predators from the brood area declined in frequency over the 15 min fry-absent period in both sexes. Standard length (age) of young was positively correlated with parental investment for females but not males. Number of young was positively correlated with parental investment for males but not for females. We conclude that post-brood-loss behaviours are search and recovery tactics that contribute to parental inclusive fitness in the event of incomplete brood predation. (C) 2008 The Association for the study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.