Early growth, dominance acquisition and lifetime reproductive success in male and female cooperative meerkats

Abstract

In polygynous species, variance in reproductive success is higher in males than females. There is consequently stronger selection for competitive traits in males and early growth can have a greater influence on later fitness in males than in females. As yet, little is known about sex differences in the effect of early growth on subsequent breeding success in species where variance in reproductive success is higher in females than males, and competitive traits are under stronger selection in females. Greater variance in reproductive success has been documented in several singular cooperative breeders. Here, we investigated consequences of early growth for later reproductive success in wild meerkats. We found that, despite the absence of dimorphism, females who exhibited faster growth until nutritional independence were more likely to become dominant, whereas early growth did not affect dominance acquisition in males. Among those individuals who attained dominance, there was no further influence of early growth on dominance tenure or lifetime reproductive success in males or females. These findings suggest that early growth effects on competitive abilities and fitness may reflect the intensity of intrasexual competition even in sexually monomorphic species.

Effects of early-life competition and maternal nutrition on telomere lengths in wild meerkats

“…Previous evidence suggests that experimental reductions of pup number, either by temporary pup removal or by contraception of subordinate females, leads to increased weight gain in the remaining pups [33,67]. Heavier pups are subsequently more likely to survive to adulthood and acquire dominance [67,68], suggesting that this accelerated growth does not exceed the optimal growth rate and therefore confers little costs. By eliminating rival offspring, dominant females are therefore likely to improve the condition, survival and probability of dominance acquisition of their own litters.…”

The importance of being beta: female succession in a cooperative breeder

“…Following English et al (2013), only females born between 01/01/1997 and 02/03/2014 were included in the analysis of beta females (02/03/2014 represents 1126 days before the end of our sampling period which is the age at which 75% of dominants had acquired their position; this restriction helps to reduce bias caused by including individuals who had not yet had sufficient time to acquire dominance). The lower date limit was the point at which the group data coverage reached a level allowing for beta positions to be tracked reliably and accurately at a monthly resolution.…”

“…In many cooperatively breeding mammals, a single dominant female virtually monopolises reproduction in each group and her offspring are reared by other group members that seldom breed successfully (Bennett & Faulkes, 2000;Clutton-Brock & Manser, 2016;Creel & Creel, 2002;Hackländer, Möstl, & Arnold, 2003;Rood, 1990;Saltzman, Digby, & Abbott, 2009). Since most females never acquire dominance, while those that do may maintain their position for several years and may breed several times a year, variance in the lifetime breeding of females is unusually high and frequently exceeds that of males (Clutton-Brock et al, 2006;Hauber & Lacey, 2005), generating strong selection among females for characteristics and strategies that enhance their ability to acquire and maintain dominant positions (Clutton-Brock et al, 2006;English, Huchard, Nielsen, & Clutton-Brock, 2013).…”

“…Female meerkats may acquire a dominant position either in their natal group or in a group they dispersed and founded, and do so either by inheriting after the death of the previous dominant female; by displacing (and usually evicting) the existing dominant female or at the founding of a new breeding group with a male(s) that have dispersed from another group (Clutton-Brock & Manser, 2016). Previous work has shown that the probability that individual females will acquire dominant status during their lifespan is associated with the status of their mothers (Hodge, Manica, Flower, & Clutton-Brock, 2008), their growth rates as pups (English et al, 2013) and the level of investment by helpers during their own development (Russell, Young, Spong, Jordan, & Clutton-Brock, 2007). In this study we describe the relative frequency with which females acquire dominant breeding status, the breeding tenure and success of individuals that acquire dominance in different ways and the traits that affect the ability of females to acquire dominant status.…”

Dominance behaviour in a non-aggressive flatfish, Senegalese sole (Solea senegalensis) and brain mRNA abundance of selected transcripts

“…The knowledge of the natural preference and the competition for different compartments is essential to avoid a misleading interpretation of results [ 29 , 31 ]. In addition, animals that acquire the dominant position in early life stages (juvenile) in fitness-related traits might expand this social status to reproductive success [ 32 , 33 ]. Therefore, the use of feeding and place preference tests adapted to Senegalese sole could provide insights into how dominance is established and expressed in a social flatfish species and such information can provide tools to establish how social interactions lead to growth dispersion and / or suppression of reproductive success.…”