干旱区生态环境知识资源中心

To understand the evolution of parental care, one needs to estimate the payoffs from providing care for the offspring and from terminating care and deserting them. In this study we estimated the payoff from care provision, and in a companion paper we analyze the payoff from offspring desertion. In the current study we experimentally investigated the influence of the number and sex of attending parents on growth and survival of offspring in the Kentish plover Charadrius alexandrinus, in two sites (A and B). Either the male or the female parent was removed from some broods at hatching of the chicks (female-only and male-only broods, respectively), whereas in control broods both parents were allowed to attend their young. At site A survival of the chicks was lower in uniparental (male-only and female-only) broods than in control broods, whereas we found no difference in brood survival at site B. Brood survival decreased over the season. Removal of either parent did not influence the growth of the young, although growth varied over the breeding season, and it was significantly different between the sites. These results suggest that the payoff from parental care decreases over the breeding season and that the value of parental care (i.e., the contribution of parents to the survival of their young) may depend on the environment.