Do female life span and fecundity of small ermine moth increase with multiple mating and adult nutrition?

Several evolutionary explanations for multiple mating in insects have been proposed, and it has been suggested that Lepidoptera benefit from the energy contained in nuptial gifts. In two closely related species of small ermine moths, Yponomeuta cagnagellus (Hübner) and Yponomeuta padellus (L.), we experimentally controlled the number of matings and access to honey as an energy source, and assessed the effects of these factors on female life span and lifetime fecundity. No positive effects of mating were found in either species. In fact, mating significantly shortened life span. The effect of access to energy in the form of honey differed between the two species. In the shorter-lived Yponomeuta padellus, access to honey did not increase the life span of mated females and did not increase fecundity. In Yponomeuta cagnagellus however, access to energy in the form of honey counteracted the negative effects of mating and females with access to honey lived significantly longer and laid significantly more eggs during their lifetime.