Resource-dependent nuptial feeding in Panorpa vulgaris: an honest signal for male quality

In mating systems that are characterized by resource-dependent male behavior like nuptial feeding, food limitation obviously plays a major role in male performance. In Panorpa vulgaris (Mecoptera: Panorpidae), the ability to produce nuptial gifts has major fitness consequences as the number of gifts determines copulation duration, which then determines the number of eggs fertilized by a given male. In the present study, we are able to show that males of P. vulgaris were limited in their production of salivary secretions. The number of saliva secretions males were able to produce declined in successive matings. Moreover, males of nutritionally high status produced more gifts than those of nutritionally low status. The proximate factor determining male saliva secretion was the development of the salivary gland, which in turn depended on the amount of food a male could access. The degree of male mating effort corresponded to the size of the salivary gland, yet while absolute investment increased with gland size, the relative investment decreased. Mating costs for males thus depend on nutritional status. Copyright 2006.