Analysis of variations of handling-time inTrichogramma maidis

Variation in handling-time is studied in the association betweenTrichogramma maidis Pintureau & Vœgelé Hym.: Trichogrammatidae] and one of its factitious hosts: the eggs of the Mediterranean flour mothEphestia kuehniella Zeller Lep.: Pyralidae]. It is shown that the duration of egg laying behaviour decreases exponentially from the first host egg encountered onwards. This decreasing kinetic, which corresponds to a learning ability, shows a high variability between females, but a mother-daughter regression analysis fails to demonstrate any genetic transmissibility of this learning ability over 2 successive generations. Once the learning is over, there remains a residual variability which is, in part, under genetic control. The possible consequences of these results on the stability of host-parasite associations are discussed.