Effects of multiple mating and adult nutrition on longevity and fecundity in two Yponomeuta species

Many male Lepidoptera transfer a large ejaculate, containing nutrients and/or secondary plant compounds. In principle this 'nuptial gift' could help to increase female survival and longevity. Here we investigated the effects of both multiple mating and extra nutrition in the adult stage on males and females in two species of Yponomeuta. Mated females had significantly shorter live spans than unmated females and similar fecundity. Females therefore do not appear to benefit from remating, which suggests that the considerable weight transfer of the males to the females during mating does not provide nutritional value. Females of Y. cagnagellus, which received honey throughout their adult lifetime, lived significantly longer and laid larger egg batches than females, that did not receive honey. In Y. padellus this effect was not found. It is concluded that neither species benefits from multiple mating and that in Yponomeuta cagnagellus adult nutrition rather then mating increases female reproductive output and longevity, which contrasts with many studies of Macrolepidoptera.