Supervisor: Denis Réale
Cooperative breeding refers to a reproductive system in which breeders (generally dominant individuals) re- produce successfully while helpers (subordinates) delay or avoid their own reproduction by remaining in the natal territory and caring for the dominants’ offspring. As adults, subordinate helpers can either become dominant in their natal territory or disperse and settle as dominants in a different territory. This social system raises several interesting evolutionary and ecological questions. For example, why would a helper - that is able to reproduce - remain in its natal territory and delay its reproduction instead of dispersing and attempting to reproduce as a dominant elsewhere? What are the mechanisms underlying this behaviour? Why do some individuals stay and become dominant on their natal territory whereas others disperse to found a new family group? Behavioural ecologists have recently started to consider the importance of personality (i.e. consistent behavioural and physiological differences between individuals)in this context. It has been shown that personality can influence the life history of an individual, and we therefore expect that it could affect its social life and the probability for it to become dominant, to help or to disperse. The subject of my study is the Alpine marmot, a cooperatively breeding rodent that inhabits the alpine meadows of Europe. Alpine marmots live in family groups composed of one dominant pair, their offspring and related or unrelated individuals. In this project I want to explore in detail the influence(if any)of personality on the sociability of this species and try to predict the social role of an individual based on its personality. To this aim I plan five main chapters of the thesis: Ch.1 Personality and social interactions; Here I will analyze the influence of an individual’s personality on the way it interacts with conspecifics, within and outside its group. I expect that personality influences the frequency and the type of social interactions of an individual. Ch.2 The ontogeny of personality and sociability; I will analyze how personality develops and how it affects the ontogeny of sociability in the marmot. I will also analyze how early social context (e.g. level of affiliative or agonistic interactions in the group) will affect the ontogeny of personality. Ch.3 The role of personality in a hierarchical social system and its interaction with kinship between individuals; in this chapter I will try to predict the future dominance status of an individual based on its personality and on the presence-absence of other competitors in the group. Using genetic data I will also test how kinship plays a role in modulating social interactions among individuals within a group and how it interacts with personality types. Ch.4 Personality, reproduction and survival; In the fourth chapter I will consider how personality affects both direct (i.e. survival and reproduction) and inclusive fitness (i.e. including the fitness of relatives). Data on reproduction and survival are collected trough observation and captures-recaptures of marked individuals. Ch.5 The effect of personality on recruitment and stability of the social group; Here I analyze how the personality of both subordinates and dominant individuals within a social group affects yearly recruitment (i.e. number of pups produced or yearlings recruited each year) and the long-term stability of the group.
Ferrari, Caterina, Cristian Pasquaretta, Claudio Carere, Elena Cavallone, Achaz von Hardenberg, Denis Réale
2013 Animal Behaviour