Nutrient uptake and allocation capacity during immature development determine reproductive capacity in Diachasmimorpha longicaudata (Hymenoptera: Braconidae: Opiinae), a parasitoid of tephritid flies

Abstract

Fitness in parasitoids is generally influenced by host quality. We measured the effects of three tephritid host species that varied in size, the fruits they developed in, and host nutritional content on some measures of fitness such as egg load, individual egg size, body size, and nutrient composition in the braconid Diachasmimorpha longicaudata, a widely used fruit fly biological control agent. The host species were: Anastrepha ludens (large host developing in both grapefruit and an artificial diet), Anastrepha obliqua (small host) and Anastrepha serpentina (small host). Female parasitoid body size was influenced by host size and the number of eggs per female varied significantly with parasitoid age (0–24h). Female parasitoids that emerged from A. obliqua and those that emerged from A. ludens reared in grapefruit had the largest eggs, whereas those that emerged from A. ludens reared in artificial diet and from A. serpentina had the smallest eggs. While nutrient concentrations differed among fly species, there was little to suggest that resources were more accessible in certain hosts. The largest host did not necessarily exhibit the highest nutrient concentration. Larger hosts represented larger macronutrient pools and the nutrient content of the host generally corresponded to the relative abundance of the same nutrients in the parasitoids that developed within them. Nevertheless, the quality of the various hosts tested had little effect on egg load, egg size and adult nutrient composition of the oligophagous parasitoid, D. longicaudata. This renders D. longicaudata a valuable candidate parasitoid for the biological control of multiple species of Anastrepha.