Linking body mass and group dynamics in an obligate cooperative breeder

Authored by Arpat Ozgul, Andrew W Bateman, Sinead English, Tim Coulson, Tim H Clutton-Brock

Date Published: 2014

DOI: 10.1111/1365-2656.12239

Sponsors: Biotechnology and Biological Sciences Research Council (BBSRC) Leverhulme Trust Swiss National Science Foundation (SNSF) Isaac Newton Trust University of Cambridge Earthwatch Institute

Platforms: R

Model Documentation: ODD Flow charts Mathematical description

Model Code URLs: Model code not found

Abstract

Social and environmental factors influence key life-history processes and population dynamics by affecting fitness-related phenotypic traits such as body mass. The role of body mass is particularly pronounced in cooperative breeders due to variation in social status and consequent variation in access to resources. Investigating the mechanisms underlying variation in body mass and its demographic consequences can help elucidate how social and environmental factors affect the dynamics of cooperatively breeding populations. In this study, we present an analysis of the effect of individual variation in body mass on the temporal dynamics of group size and structure of a cooperatively breeding mongoose, the Kalahari meerkat, Suricata suricatta. First, we investigate how body mass interacts with social (dominance status and number of helpers) and environmental (rainfall and season) factors to influence key life-history processes (survival, growth, emigration and reproduction) in female meerkats. Next, using an individual-based population model, we show that the models explicitly including individual variation in body mass predict group dynamics better than those ignoring this morphological trait. Body mass influences group dynamics mainly through its effects on helper emigration and dominant reproduction. Rainfall has a trait-mediated, destabilizing effect on group dynamics, whereas the number of helpers has a direct and stabilizing effect. Counteracting effects of number of helpers on different demographic rates, despite generating temporal fluctuations, stabilizes group dynamics in the long term. Our study demonstrates that social and environmental factors interact to produce individual variation in body mass and accounting for this variation helps to explain group dynamics in this cooperatively breeding population.

Tags

Individual-based model growth Population-dynamics Environmental-change Group-size Social-structure Sex-differences Life-history Meerkats suricata-suricatta Subordinate reproduction