Genetic variation in patch time allocation in a parasitic wasp

1.The intra‐patch experience acquired by foraging parasitoid females has often been considered to have a strong influence on their tendency to leave a patch, and thus on their total patch residence time. Most studies that have been performed on this subject suggest that the patch‐leaving rules observed are adaptive because they enable the females to adjust their patch residence time to local environmental conditions.2.Considering a behavioural rule as being adaptive supposes that it has been progressively settled by natural selection, and thus that there is, in the population, genetic variation on which the natural selection could act.3.Therefore, this study aimed to discover whether there was indeed genetic variability in the patch‐leaving decision rules in a population of the egg parasitoid speciesTelenomus busseolae, which attacks patches of its hosts, the eggs ofSesamia nonagrioides. Different wasp families were compared using the isofemale lines method, and the behavioural records were analysed by means of a modified version of the Cox's proportional hazards model proposed byHaccouet al. (1991) andHemerik, Driessen & Haccou (1993).4.The results obtained show thatT. busseolaefemales increase their tendency to leave the patch after each successful oviposition. Each host rejection also led to an increase in the tendency to leave the patch, but this effect was smaller when host rejections were observed between two ovipositions occurring in rapid succession. Subsequent visits to the patch also increased the patch‐leaving tendency.5.Genetic variability was found in both the global patch‐leaving tendency and in the effect that successful ovipositions and host rejections have on this tendency.6.The adaptive and evolutionary consequences of these results are discussed.