Behavioral Ecology Vol. 12 No. 6: 659-665
© 2001 International Society for Behavioral Ecology
Conflict of interest between sexes over cooperation: a supergame on egg carrying and mating in a coreid bug
a Department of Theoretical Ecology, Ecology Building, University of Lund, S-223 62 Lund, Sweden b Department of Biology, University of Oulu, Box 3000, Fin-90 014 Oulu, Finland
Address correspondence to R. Härdling, who is now at Graham Kerr Building, University of Glasgow, Glasgow G12 8QQ, UK. E-mail: rfh1n{at}udcf.gla.ac.uk .
In the golden egg bug (Phyllomorpha laciniata Vill. Heteroptera: Coreidae) females lay eggs on the backs of conspecifics, often on courting males. Although the bugs do not provide care to the eggs, this decreases the risk of egg predation. As an effect males carry many eggs which are not their own. The male and female interests are in conflict; females need to find an oviposition site, and male fitness depends on the obtained number of matings. By using a very rare modeling approach, a supergame where the individuals actions change payoffs over time, we show that combinations of reciprocating strategies where males obtain a mating in return for a carried egg can be stable. The value of the mating, to males, is more important than the relatedness to the eggs in gaining their cooperation in carrying eggs. Females may also take advantage of the males without reciprocating. This is especially likely if the probability of future meeting is high and the value of a mating is high for the male. We relate our results to our own data from empirical studies and experiments on the species. In the light of the results we discuss the behavior of the bugs in relation to nuptial gifts. We also discuss the general applicability of the supergame approach.
Key words: cooperation, egg-laying, mating, Phyllomorpha, sexual conflict, supergame.