We investigated the influence of sugar foods presented in a bottle-type feeding device on female longevity and life-time fecundity of Cotesia vestalis, a larval parasitoid of the diamondback moth Plutella xylostella. Solutions of honey and sugar mixture (sucrose, glucose and fructose) prolonged female longevity significantly more than water, irrespective of the mating status and oviposition experience. These sugar foods also significantly enhanced life-time fecundity of mated parasitoids more than water. We also investigated the continuity of these sugar foods in bottle-type feeding devices installed in a greenhouse for different periods (30 and 120 days). Even 120 days after the installation of these feeding devices, honey and sugar mixtures in feeding devices could respectively enhance female longevity in laboratory experiments. These results indicated that those sugar foods provided by bottle-type feeding devices are useful for maintaining the parasitoids for at least several months in a greenhouse where potential sugar sources (e.g. flowers) are limited.
