978–0–19–969257–6 04-Royle-c04-drv Royle-et-al (Typeset by SPi, Chennai) 62 of 347 March 31, 2012 14:59 OUP UNCORRECTED PROOF – REVISES, 31/3/2012, SPi CHAPTER 4 Patterns of parental care in vertebrates Sigal Balshine 4.1 Introduction Understanding parental care behaviour has remained a core research area in evolutionary behavioural ecology. Why the fascination with parental behaviour? Many human cultures have a strong focus on children and parenting and our extensive and prolonged care for our own young undoubtedly contributes to our fascination with parental care in other animals. Also by studying parental care, behavioural scientists can gain a useful window on the social dynamics of family groups, providing insights on sexual conflict (Chapter 9), parent–offspring conflict (Chapter 7), sibling rivalry (Chapter 8), and kin-mediated cooperation (Emlen 1994, 1997). The strong link between parental effort and mating effort (and sexual selection patterns in general) has also driven the ever-growing interest in parental behaviour (Williams 1966; Trivers 1972; Emlen and Oring 1977; Kokko and Jennions 2008). Parental care varies widely between species. While costly parental feeding of offspring is a near hallmark feature of birds and mammals, many species of fishes, amphibians, and reptiles also provide care for young by simply but vigorously guarding young against predators. Whether it is the mother or the father that defends the brood also varies widely between species. Understanding the key ecological factors selecting for care and explain- ing the plethora of parental care forms across dif- ferent taxa has remained an enduring challenge in evolutionary behavioural ecology (Lack 1968; Gross 2005; Kvarnemo 2010). Empirical research has shown that providing care benefits parents by increasing offspring survival and increasing their reproductive success. However, parental care also has three potential costs: 1) a decrease in parental survival, 2) decreased growth and associated fecun- dity reduction, and 3) fewer remating opportu- nities (Gross and Sargent 1985). Scientists have used these costs and benefits to better understand when care will evolve and which sex will provide care (Maynard-Smith 1977; Balshine-Earn and Earn 1997; Houston et al. 2005). Vertebrate groups that show great variation in care types, like teleost fishes and shorebirds, have been particular useful models in the search for a better understanding of the evo- lution of parental behaviour. Since Clutton-Brock (1991) published his ency- clopedic bible on parental care, two new tech- nological advances (both molecular) have helped to further invigorate parental care research. First, phylogenetically based, comparative studies are now commonly employed in the study of parental care. The molecular revolution has facilitated the wide scale availability of molecular phylogenies, and analysis that links behaviour to these (Good- win et al. 1998). These phylogenetic studies have strongly augmented and guided the more tradi- tional behavioural ecology approach of experimen- tal manipulation (Wright and Cuthill 1989). Second, the growth of genomic and bioinformatic studies has facilitated investigations into the divergence or conservation of genes, gene networks, and gene regulation across species or genera that share sim- ilar behaviour. Both these new directions have been made possible because of the rapid expansion of molecular data and because of impressive compu- tational improvements that have facilitated large- scale database creation and analysis. In general, the molecular revolution is providing deep insights 62