1. Dunbar, R. I. M. in Perspectives in Ethology Vol. 5 (eds Bateson, P. P. G. & Klopfer, P. H.) 385–431 (Plenum, New York, 1982).
2. Alcock, J. in Sexual Selection and Reproductive Competition in Insects (eds Blum, M. S. & Blum, N. A.) 381–402 (Academic, New York, 1979).
3. Arak, A. in Producers and Scroungers (ed. Barnard, C. J.) 154–194 (Croom Helm, London, 1984).
4. Zimmerer, E. J. & Kallman, K. D. Evolution 43, 1298–1307 (1989).
5. Ryan, M. J., Pease, C. M. & Morris, M. R. Am. Nat. 139, 21–31 (1992).