Increased food availability raises eviction rate in a cooperative breeding mammal.

C Dubuc,H C Spence-Jones,S P Sharp,B Dantzer,D Gaynor,S English,T H Clutton-Brock,N Thavarajah

doi:10.1098/rsbl.2016.0961

C Dubuc, H C Spence-Jones + Show 6 more

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https://doi.org/10.1098/rsbl.2016.0961

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Abstract

In group-living mammals, the eviction of subordinate females from breeding groups by dominants may serve to reduce feeding competition or to reduce breeding competition. Here, we combined both correlational and experimental approaches to investigate whether increases in food intake by dominant females reduces their tendency to evict subordinate females in wild meerkats (Suricata suricatta). We used 20 years of long-term data to examine the association between foraging success and eviction rate, and provisioned dominant females during the second half of their pregnancy, when they most commonly evict subordinates. We show that rather than reducing the tendency for dominants to evict subordinates, foraging success of dominant females is positively associated with the probability that pregnant dominant females will evict subordinate females and that experimental feeding increased their rates of eviction. Our results suggest that it is unlikely that the eviction of subordinate females serves to reduce feeding competition and that its principal function may be to reduce reproductive competition. The increase in eviction rates following experimental feeding also suggests that rather than feeding competition, energetic constraints may normally constrain eviction rates.

Highlights

In group-living mammals, adult females may leave their natal groups voluntarily when food competition increases (e.g. African lions, Panthera leo, California ground squirrels, Otospermophilus beecheyi [1]), while in some cooperative breeders, dispersal is commonly imposed by breeding females who commonly evict subordinate females from the group
All data used in our analyses were collected at the Kuruman River Reserve, South Africa, as part of the long-term Kalahari Meerkat Project (KMP) which has followed more than 60 different groups of wild meerkats over 20 years [4]
Our aim was to investigate whether food competition stimulates the eviction of subordinate females by dominants in wild Kalahari meerkats

Summary

Introduction

In group-living mammals, adult females may leave their natal groups voluntarily when food competition increases (e.g. African lions, Panthera leo, California ground squirrels, Otospermophilus beecheyi [1]), while in some cooperative breeders, dispersal is commonly imposed by breeding females who commonly evict subordinate females from the group (e.g. meerkats, Suricata suricatta, banded mongooses, Mungos mungo [1,2]). We use a combination of long-term records of the behaviour of individuals and experiment in which we increased the food intake of dominant females in wild meerkats (S. suricatta) to investigate whether foraging success affects the tendency of dominants to evict subordinates. Pregnant dominant females evict subordinate females from the group when they reach an age when their weight approaches that of dominant females and the frequency with which they attempt to breed

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