Effects of Dietary Fatty Acids on the Fecundity of the Endoparasitoid Pimpla turionellae L. (Hymenoptera: Ichneumonidae)

Abstract

Synovigenic parasitoids rely on adult feeding to increase their reproductive potential. Here, we examined the impact of fatty acid composition in the artificial diet on the fecundity and hatchability of the endoparasitoid Pimpla turionellae
L. adult females. Females were provided with natural diet (honey and host pupae), a basic chemically-defined synthetic diet, or five different synthetic diets without palmitic, stearic, oleic acid, linoleic acid or linolenic acid separately, or all
fatty acids. The effects of dietary fatty acid deficiency on total and age-dependent fecundity and hatchability of the parasitoid were investigated. Females fed with natural diet laid 27.4 eggs throughout a period of 15 d, and 78.96% of
these eggs hatched. The highest fecundity was observed with females fed with basic synthetic diet, a stearic-and palmitic acid-free diet or an oleic acid-free diet. Females provided with linoleic acid- and all fatty acids-free diets had the lowest
fecundity. The highest egg hatching (84.76%) was observed with females fed with the basic synthetic diet whereas fatty acid-free diet reduced egg hatching to 57.05%. Age-dependent fecundity increased from day 20 to 28 and then decreased
on day 31. Egg hatchability of females provided with linoleic or linolenic acid-free diets were similar to those fed with all fatty acid-free diet. Relative to basic synthetic diet, linoleic or linolenic acid-free and all fatty acids-free diets significantly reduced total and diet-dependent egg hatchability. These results have important implications for
understanding both the lipid allocation strategy and the impact of fatty acids alone and in combination on reproduction of this parasitoid, which are used as important biological control agent.