Helpers increase the reproductive potential of offspring in cooperative meerkats

Abstract

In both animal and human societies, individuals may forego personal reproduction and provide care to the offspring of others. Studies aimed at investigating the adaptive nature of such cooperative breeding systems in vertebrates typically calculate helper 'fitness' from relationships of helper numbers and offspring survival to independence. The aim of this study is to use observations and supplemental feeding experiments in cooperatively breeding meerkats, Suricata suricatta, to investigate whether helpers influence the long-term reproductive potential of offspring during adulthood. We show that helpers have a significant and positive influence on the probability that offspring gain direct reproductive success in their lifetimes. This effect arises because helpers both reduce the age at which offspring begin to reproduce as subordinates and increase the probability that they will compete successfully for alpha rank. Supplemental feeding experiments confirm the causality of these results. Our results suggest that one can neither discount the significance of helper effects when none is found nor necessarily estimate accurately the fitness benefit that helpers accrue, unless their effects on offspring are considered in the long term.

Experimental peripheral administration of oxytocin elevates a suite of cooperative behaviours in a wild social mammal

“…Prosocial behaviours also bring indirect (kin-selected) benefits to the practitioners by increasing the direct fitness of other (usually closely related [20]), group members. Feeding and caring for pups improve their likelihood of survival [31] and attaining dominance [32]. Other adult group members benefit in similar ways to the prosocial individual through access to common goods in the form of a system of well-maintained and prolific shelter burrows [26], and from improved predator detection and alarms given by guarding individuals [24].…”

Natal territory size, group size, and body mass affect lifetime fitness in the cooperatively breeding Florida Scrub-Jay

“…Strong evidence exists that the presence of helpers during the natal rearing period can enhance the growth, development, and condition of young, leading to higher juvenile survival (Hatchwell et al 2004, Hodge 2005, Ridley 2007, Sparkman et al 2010, earlier age at first breeding (Hodge 2005, Russell et al 2007, and higher adult survival later in life (Sparkman et al 2010, Brouwer et al 2012. Collectively, these studies suggest that variation in the early social environment of cooperative breeders can influence the lifetime reproductive fitness of individuals.…”

Strategic female reproductive investment in response to male attractiveness in birds

“…We, therefore, suggest that research should move away from simply assessing patterns of female investment and towards studies that integrate manipulation of male attractiveness with estimation of offspring and female fitness (including the trade-off between current and future reproduction), preferably in ecologically relevant contexts (see e.g. [73,74], for a similar approach in the context of cooperative breeding).…”