GENETIC SIRE EFFECTS ON THE FIGHTING ABILITY OF SONS AND DAUGHTERS AND MATING SUCCESS OF SONS IN A SCORPIONFLY

Field-collected males of the scorpionfly Panorpa vulgaris (Insecta: Mecoptera: Panorpidae) were separated on the basis of whether or not they could produce salivary nuptial food during matings in the laboratory. Adult males must feed to secret salivary nuptial gifts. Males who could secrete saliva during mating were designated nutritionally 'high' and males who could not were designated nutritionally 'low'. This designation may reflect differences in the ability of the two types of males to compete with conspecifics for food in the habitat. Nutritionally high and nutritionally low fathers were paired haphazardly with virgin mates, all of whom were full siblings. The adult sons of nutritionally high fathers won significantly more fights and mates than the sons of nutritionally low fathers when the two were placed in competition for food. The adult daughters of nutritionally high fathers won significantly more fights in competition with adult daughters of nutritionally low fathers. These sire effects on offspring performance were not confounded by body size differences of contestants. Bilateral symmetry is heritable, differs significantly between the two sire categories and between the offspring of the sire categories, and nutritionally low sires and their offspring are more bilaterally asymmetrical. The genetic paternal effects on offspring fitness components may give rise to female choice based on genetic quality of potential sires. © 1992 The Association for the Study of Animal Behaviour.