Behavioural trait assortment in a social network: patterns and implications
- 1.8k Downloads
The social fine structure of a population plays a central role in ecological and evolutionary processes. Whilst many studies have investigated how morphological traits such as size affect social structure of populations, comparatively little is known about the influence of behaviours such as boldness and shyness. Using information on social interactions in a wild population of Trinidadian guppies (Poecilia reticulata), we construct a social network. For each individual in the network, we quantify its behavioural phenotype using two measures of boldness, predator inspection tendency, a repeatable and reliably measured behaviour well studied in the context of co-operation, and shoaling tendency. We observe striking heterogeneity in contact patterns, with strong ties being positively assorted and weak ties negatively assorted by our measured behavioural traits. Moreover, shy fish had more network connections than bold fish and these were on average stronger. In other words, social fine structure is strongly influenced by behavioural trait. We assert that such structure will have implications for the outcome of selection on behavioural traits and we speculate that the observed positive assortment may act as an amplifier of selection contributing to the maintenance of co-operation during predator inspection.
KeywordsBehavioural phenotype Co-operation Evolutionary graph theory Guppy Personality Poecilia reticulata Predator inspection
We would like to thank P. Thomas, M. Botham, J. Dyer, J. Ward and C. Piyapong for assistance with data collection and Graeme Ruxton and two anonymous referees for valuable comments on a previous version of this manuscript. Funding was provided to DPC by NERC (NE/E001181/1) and JK by the EPSRC (GR/T11241/01(P)).
- Croft DP, James R, Krause J (2008) Exploring animal social networks. Princeton University Press, Princeton, NJGoogle Scholar
- Dugatkin LA, Wilson DS (2000) Assortative interactions and the evolution of cooperation during predator inspection in guppies (Poecilia reticulata). Evol Ecol Res 2:761–767Google Scholar
- Krause J, Ruxton GD (2002) Living in groups. Oxford University Press, OxfordGoogle Scholar
- Magurran AE (1993) Individual differences and alternative behaviours. In: Pitcher TJ (ed) Behaviour of teleost fishes, 2nd edn. Chapman & Hall, LondonGoogle Scholar
- Maynard Smith J (1982) Evolution and the theory of games. Cambridge University Press, CambridgeGoogle Scholar
- Newman MEJ (2003) Mixing patterns in networks. Phys Rev E 67:art. no.-026126Google Scholar
- Ohguchi O (1978) Experiments on the selection against colour oddity of water fleas by three-spined stickelbacks. Z Tierpsychol 47:254–267Google Scholar
- Wilson EO (1975) Sociobiology: the new synthesis. Harvard University Press, Cambridge, MAGoogle Scholar