The evolution of individual foraging specialisation in a group-living mammal

Abstract

Individual foraging specialisation has received much attention in the past few decades, however the causes and consequences of such specialisation in group-living and cooperative species remain poorly understood. These species merit special consideration as many of the key drivers associated with individual foraging specialisation, such as intrapopulation competition and social learning, are likely to be influenced by the intensified local social environment. In this thesis, I aim to investigate such social influences on individual foraging niche. I first explore current theory behind individual foraging specialisation and apply this to the social group in order to predict how living in groups may impact the development of such specialisation (Chapter 1). I also discuss the consequences of between-individual variation in foraging niche and consider how the development of this may feedback on the social environment of group- living species (Chapter 1). Following my review of current theoretical and empirical work in Chapter 1, I investigate the causes of individual foraging specialisation in a population of wild banded mongooses, Mungos mungo. I begin by outlining the general methods used in this thesis, detailing the study species, study site, data collection and sample preparation and processing (Chapter 2). Presenting my findings, I first show that increasing group size results in smaller individual foraging niche, suggesting that intragroup competition drives individual foraging specialisation (Chapter 3). Second, I present evidence for the non-genetic social inheritance of foraging niche and explore the influence of role models on the transmission of behavioural traditions (Chapter 4). This work highlights that the social group environment, in particular increased local competition and 2 opportunity for social learning, has a substantial effect on individual foraging niche in banded mongooses. I hypothesise that the ability to specialise may reduce intragroup competition, promoting group stability and propose further work to explore how living in groups influences both the causes and consequences of individual foraging specialisation.