The Courtship Behaviour of Mormoniella Vitripennis Walk. (Hymenoptera, Pteromalidae)

The courtship behaviour pattern of M. vitripennis Walk. is described. Copulation does not occur in the host puparium, probably because there is not sufficient space. A swaying of the male's body sometimes occurs just before mounting. This must help the male to see the female. The chasing movement which normally precedes mounting is a response to visual stimuli. This response can be evoked by the movement of a pencil mark in relation to the male. After mounting a male moves over the female's body until the female is still. Also, a male only performs courtship movements when the female is still. The result of these two facts is that the courtship is performed in the correct position. The significance of the male's courtship movements is considered and a new type of releasing situation is described in which the male responds to an absence of something which was formerly present. Copulation differs from the typical consummatory act in that it is not the termination of the behaviour pattern and also, it is not associated with any marked reduction in the tendency to repeat the pattern. The courtship behaviour pattern is innate. Figures 7 and 8 show the behaviour of the male and female, respectively, as reaction chains.