Raihani, NJ;
(2008)
Cooperation and conflict in pied babblers.
Doctoral thesis , University of Cambridge.
Abstract
Cooperative breeding occurs when individuals receive assistance from others in the production of young. Research attention has traditionally focussed on explaining how reproductive altruism can be reconciled with evolutionary theory; however in recent years, more emphasis has been placed on examining the extent of cooperation and conflict within cooperative societies. In this thesis, I present data on conflict and cooperation in cooperatively breeding pied babblers. In Chapter Three, I show that dispersal patterns dictate the circumstances under which helpers encounter unrelated individuals and attempt to breed, and suggest that sex-biases in dispersal might therefore be an important determinant of breeder-helper conflict in cooperative species. Chapter Four describes correlations between dispersal patterns and juvenile aggression: females, the dispersing sex, are more aggressive than males, and more aggressive females disperse earlier than less aggressive females. I then go on to examine offspring care in this species, focussing on food-associated ‘purr’ calls that are given by adults when feeding young. Most studies have shown that the function of food-calling is to ‘switch-on’ nestling begging; however, I found that adult pied babblers continue to use purr calls after young have fledged, and that their primary function is to move mobile offspring around the territory, rather than to elicit begging (Chapter Five). Chapter Six demonstrates that adults actively condition young to associate purr calls with food. Finally, I address trade-offs in cooperatively breeding species in two contexts. First, I show that the decision to fledge young depends critically on group size and the risk of nestling predation: in smaller groups, where predation risk is higher, adults fledge young earlier. This is traded off against allowing young a longer period to develop in the nest (Chapter Seven). I then discuss the trade-off between investing in current and future young and how this might be alleviated by the presence of non-reproductive helpers that care for first-born young, liberating breeders to initiate subsequent broods. Although this is thought to be common among cooperative breeders, the mechanism by which the care of different subsets of offspring is divided between breeders and helpers is not known. In Chapter Eight, I show that breeder-offspring aggression transfers first-born young to helpers; thereby achieving an inter-brood division of labour.
| Type: | Thesis (Doctoral) |
|---|---|
| Title: | Cooperation and conflict in pied babblers |
| Event: | University of Cambridge |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences > Experimental Psychology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1517091 |
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