Impacts of differences in nutritional quality of wingless and winged aphids on parasitoid fitness

Abstract

Winged aphids are described as hosts of lesser quality for parasitoids because a part of their resources is used to produce wings and associated muscles during their development. Host lipid content is particularly important for parasitoid larvae as they lack lipogenesis, therefore, they rely entirely on the host for this resource. The goal of this study is to determine in what extent winged and wingless aphids differ from the nutritional point of view and if these differences impact the parasitoid fitness notably the lipid content. We analysed the energetic budget (proteins, lipids and carbohydrates) of aphids of different ages (third, fourth instars and adults) according to the morph (winged or wingless). We also compared fitness indicators for parasitoids emerging from winged and wingless aphids (third and fourth instars). We found that in third instars, parasitoids are able to inhibit wing development whereas not in fourth instars. Both winged instars allow the production of heavier and fattier parasitoids. The presence of wings in aphids seems to have little effect on the fitness of emerging parasitoids and did not modify female choice for oviposition. Finally, we demonstrate that Aphidius colemani, used as a biological control agent is able to parasite wingless as well as winged Myzus persicae at least the juvenile stages. If the parasitism occurs in third instars, the parasitoid will prevent the aphid from flying, which could in turn reduce the virus transmission.