A carbohydrate-rich diet increases the lifetime potential fecundity, longevity and egg resorption in a forest parasitoid.

SUANS, M.A.; FISCHBIEN, D.; CORLEY, J.C.; CASTELO, M.K.

Ciudad Autónoma de Buenos Aires

Conferencia; 7th International Entomophagous Insects Conference (7IEIC); 2023

FCEN-UBA, FAUBA, INTA, CEPAVE

Diet is one of the factors that mostly influence the fitness components in parasitoids, particularly for synovigenic species, which need to mature their oocytes after emergence. In laboratory, we investigated the effect of a carbohydrate-rich diet on: (1) longevity, (2) egg maturation and resorption rates, and (3) lifetime potential fecundity on the larval parasitoid Megarhyssa nortoni (Hymenoptera: Ichneumonidae). In separate experiments, newly emerged M. nortoni females were provided with water or honey ad libitum until death or for different time intervals: 5, 10, 15, 20 and 25 days. Next, ovaries of females of each age cohort were dissected, and we counted the total number of mature, immature and resorbing oocytes. As expected, females lived significantly longer when they fed on the honey-based diet. Lifetime potential fecundity and egg resorbing rates also increased with diet, and egg resorption started at 5 days-old for both water and honey-fed females. In addition, the egg maturation was solely influenced by diet on females of five days-old, reaching the highest egg load at 5 days-old and 10 days-old for water and honey-fed females, respectively. Results also showed that M. nortoni is an extreme synovigenic parasitoid, as females emerged with no mature oocytes. We explore here for the first time the reproductive strategies of one of the most important biocontrol agents of invasive populations of Sirex noctilio (Hymenoptera: Siricidae) in the Southern Hemisphere.