Behavioural Ecology


Behavioural ecology investigates how animal behaviour is adapted to the physical and social environment of individuals. Over the past 40 years behavioural ecology has been established as a field of research in which both empirical and theoretical studies analyse how evolution has shaped animal behaviour through the process of natural selection. The underlying premise is that individuals adopt strategies (behaviours) that maximise their fitness, that is, the contribution of their genes to future populations. Behavioural ecology seeks to understand why a specific behaviour confers a fitness advantage to an individual given a set of ecological and social conditions. The adoption of methods from genetics, physiology, bioinformatics and developmental biology has greatly expanded the tool kit with which questions in behavioural ecology are addressed.

Key Concepts:

  • Behavioural ecology is the study of how animal behaviour is adapted to the physical and social environment through natural selection.

  • Key concepts in behavioural ecology are the comparative approach, game theory, the optimality approach.

  • Animals are assumed to tradeoff between costs and benefits of different behaviours, for example between maximising food intake or reproduction at a given time.

  • Competitive interactions often evolve into evolutionary stable strategies, situations where frequency‚Äźdependent dynamics are in equilibrium.

  • Conflicts exist between species, between members of a species and between genetic elements within individuals; these often result in arms races where exploitation and defences evolve progressively in response to each other.

  • New molecular, genetic and bioinformatic tools are opening up new questions in behavioural ecology, for example in phenotypic plasticity and epigenetics.

Keywords: evolution; behaviour; fitness; optimality; evolutionarily stable strategy (ESS)

Figure 1.

The number of leatherjackets the starling should pick up depends on how much time the bird spends searching and how long it takes to travel to the nest. The load curve (red line) represents a curve of diminishing returns, that is, the more time the bird spends searching the fewer prey items it will find. The optimal rate of delivery to the nest is found by drawing a tangent to the load curve starting from the travel time estimate on the x‐axis. For instance, the optimal number of prey items the bird is expected to pick up is a when travel time to the nest is long. By contrast, if the nest is near, the bird should pick up only b number of leatherjackets. Redrawn from Krebs and Davies .

Figure 2.

Parker's results illustrating the development of an ESS for male dung flies leaving mating sites. (a) The number of male flies on a cow pat declines over time. Some males leave within the first hour to find new pats that will attract more females. Other males remain longer and experience less competition over the small number of late‐arriving females. (b) The reproductive success of males on a pat is constant over time, because the balance between high male–male competition in the early stages and the scarcity of females later. The population has reached an ESS where all male strategies have the same pay‐off. Redrawn from Parker , by permission of Wiley.



Arnqvist G and Rowe L (2002) Antagonistic coevolution between the sexes in a group of insects. Nature 415(6873): 787–789.

Axelrod R and Hamilton WD (1981) The evolution of cooperation. Science 211: 1390–1396.

Burt A and Trivers R (2006) Genes in Conflict: The Biology of Selfish Genetic Elements. Cambridge, MA: Harvard University Press.

Chapman T, Liddle LF, Kalb JM, Wolfner MF and Partrige L (1995) Cost of mating in Drosophila melanogaster females is mediated by male accessory gland products. Nature 373(6511): 241–244.

Crook JH and Gartlan JS (1966) Evolution of primate societies. Nature 210(5042): 1200.

Davies NB (2000) Cuckoos, Cowbirds and Other Cheats. London: T & AD Poyser Ltd.

Davies NB and Welbergen JA (2009) Social transmission of a host defense against cuckoo parasitism. Science 324(5932): 1318–1320.

Duckworth RA (2009) The role of behavior in evolution: a search for mechanism. Evolutionary Ecology 23: 513–531.

Edward DA, Fricke C and Chapman T (2010) Adaptations to sexual selection and sexual conflict: insights from experimental evolution and artificial selection. Philosophical Transactions of the Royal Society B: Biological Sciences 365(1552): 2541–2548.

Foster KR (2011) The sociobiology of molecular systems. Nature Reviews Genetics 12: 193–203.

Grafen A (1984) Natural selection, kin selection and group selection. In: Krebs JR and Davies NB (eds) Behavioural Ecology: An Evolutionary Approach, 2nd edn, pp. 62–84. Oxford: Blackwell.

Grozinger CM (2010) Genomic approaches to behavioural ecology and evolution. In: Westneat DF and Fox CW (eds) Evolutionary Behavioural Ecology, pp. 488–505. Oxford: Oxford University Press.

Hager R, Cheverud JM and Wolf JB (2012) Genotype dependent responses to levels of sibling competition over maternal resources in mice. Heredity 108: 515–520.

Hager R and Johnstone RA (2003) The genetic basis of family conflict resolution in mice. Nature 421: 533–535.

Haig D and Graham C (1991) Genomic imprinting and the strange case of the insulin‐like growth factor II receptor. Cell 64: 1045–1046.

Hamilton WD (1964a) The genetical evolution of social behaviour. I. Journal of Theoretical Biology 7(1): 1–16.

Hamilton WD (1964b) The genetical evolution of social behaviour. II. Journal of Theoretical Biology 7: 17–52.

Hinde CA, Johnstone RA and Kilner RM (2010) Parent‐offspring conflict and coadaptation. Science 327: 1373–1376.

Kacelnik A (1984) Central place foraging in starlings (Sturnus vulgaris). I. Patch residence time. Journal of Animal Ecology 53: 283–299.

Krebs JR and Davies NB (1993) An Introduction to Behavioural Ecology, 3rd edn, Oxford: Blackwell Science.

Lack D (1968) Ecological Adaptation for Breeding in Birds. London: Methuen.

Laland KN, Sterelny K, Odling‐Smee J, Hoppitt W and Uller T (2011) Cause and effect in biology revisited: is Mayr's proximate‐ultimate dichotomy still useful. Science 334(6062): 1512–1516.

MacArthur RH and Pianka ER (1966) On optimal use of a patchy environment. American Naturalist 100: 603–609.

Maynard Smith J (1982) Evolution and the Theory of Games. Cambridge: Cambridge University Press.

Milinski M and Heller R (1978) Influence of a predator on the optimal foraging behaviour of sticklebacks (Gasterosteus aculeatus L.). Nature 275(5681): 642–644.

Neumann J and Morgenstern O (1944) Theory of Games and Economic Behavior. Princeton: Princeton University Press.

Nowak MA and Sigmund K (1993) A strategy of win‐stay, lose‐shift that outperforms tit‐for‐tat in Prisoner's Dilemma. Nature 364: 56–58.

Nowak MA and Sigmund K (1998) Evolution of indirect reciprocity by image scoring. Nature 393(6685): 573–577.

Nowak MA (2006) Five rules for the evolution of cooperation. Science 314(5805): 1560–1563.

Owens IPF (2006) Where is behavioural ecology going? Trends in Ecology and Evolution 21(7): 356–361.

Parker GA (1970) The reproductive behaviour and the nature of sexual selection in Scatophaga stercoraria L. Diptera: Scatophagidae) II. Journal of Animal Ecology 39: 205–228.

Sherman PW (1977) Nepotism and the evolution of alarm calls. Science 197(4310): 1246–1253.

Tinbergen N (1963) On aims and methods of ethology. Zeitschrift für Tierpsychologie 20: 410–433.

Traulsen A and Nowak MA (2006) Evolution of cooperation by multilevel selection. Proceedings of the National Academy of Sciences of the USA 103(29): 10952–10955.

Trivers RL (1974) Parent–offspring conflict. American Zoologist 14: 249–264.

West SA, Griffin AS and Gardner A (2007a) Social semantics: altruism, cooperation, mutualism, strong reciprocity and group selection. Journal of Evolutionary Biology 20: 415–432.

West SA, Griffin AS and Gardner A (2007b) Evolutionary explanations for cooperation. Current Biology 17(16): R661–R672.

Williams GC (1966) Adaptation and Natural Selection. Princeton: Princeton University Press.

Wilson DS and Wilson EO (2007) Rethinking the theoretical foundation of sociobiology. Quarterly Review of Biology 82(4): 327–348.

Young LJ and Wang Z (2004) The neurobiology of pair bonding. Nature Neuroscience 7(10): 1048–1054.

Further Reading

Alexander RD (1974) The evolution of social behaviour. Annual Review of Ecology and Systematics 5: 325–383.

Davies NB, Krebs JR and West SA (2012) An Introduction to Behavioural Ecology, 4th edn. Oxford: Blackwell Science.

Keller L (1999) Levels of Selection in Evolution. Princeton: Princeton University Press.

Krebs JR and Davies NB (1997) Behavioural Ecology, 4th edn. Oxford: Blackwell Science.

Rice WR (1996) Sexually antagonistic male adaptation triggered by experimental arrest of female evolution. Nature 381: 232–234.

Szekely T, Moore A and Komdeur J (2010) Social Behaviour: Genes, Ecology and Evolution. Cambridge: Cambridge University Press.

Trivers RL (1971) The evolution of reciprocal altruism. Quarterly Review of Biology 46: 35–57.

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Hager, Reinmar, and Gini, Beatrice(Jul 2012) Behavioural Ecology. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0003217.pub2]