Dynamics of biparental care in a burying beetle: experimental handicapping results in partner compensation

Abstract

Negotiation models of biparental care predict that parents should partially compensate for a reduction in the level of care that their partner provides. A number of studies, mostly with monogamous birds, have tested this prediction by removing or manipulating the level of effort of one parent and then measuring the response of the other parent. In this study, we test this prediction with the burying beetle Nicrophorus orbicollis, which breeds on small vertebrate carcasses and provides biparental care to their young. We reduced the effort of either the male or female parent by attaching a weight to their elytron and evaluated the effect that their reduction in time spent providing care had on their partner’s level of effort during the carcass preparation stage of reproduction. After their partner was weighted, males increased the time spent preparing the carcass by 28 %. Females were already spending nearly 100 % of their time working and observed changes in effort were negligible. Our results show that parents directly monitor their partner’s level of effort in the carcass preparation stage of reproduction. This is the first handicapping study in an invertebrate species to provide support for the negotiation model of intersexual conflict over parental investment.