Sexual conflict, the different interests of males and females over reproduction, is a potent evolutionary force. Here I investigate sexual conflict in the context of parental care by focussing on two questions: (i) which behavioural, morphological and environmental traits influence the parents’ decision to care for the brood or desert? (ii) How does sexual conflict influence the evolution of behaviour and morphology? I investigate both questions using a small, polygamous passerine bird, the Eurasian penduline tit Remiz pendulinus, which exhibits intense sexual conflict over parental care such that either the male, the female or both parents desert the clutch. Using detailed behavioural observations during the crucial few days preceding desertion, I argue that it may be in the parents’ best interest to conceal their intention to care for (or desert) their brood. The rapid resulting process that leads to variable parental care resembles a coordination game in which either parent may desert first. I developed a game-theoretical model that suggests that a key to resolving the conflict between parents is the sex difference in reproductive payoffs for given parental care strategies, rather than differences in parental quality per se. Environmental variables (e.g. food availability and mating opportunities) seem only subsidiary in the decision-making process of parents. My final chapter explores ramifications of sexual conflict at an evolutionary timescale. By comparing the highly polygamous Eurasian penduline tit with the monogamous Cape penduline tit, I show that morphological and behavioural differences between these two species are consistent with predictions of sexual conflict theory. During my PhD I also identified that there is considerable variation in breeding systems within different species of penduline tits. I argue that by studying these systems new insights will emerge into (i) the drivers of breeding systems, and (ii) neural and genomic traits that underlie breeding system evolution.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:507745 |
| Date | January 2009 |
| Creators | van Dijk, Rene E. |
| Contributors | Szekely, Tamas |
| Publisher | University of Bath |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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