Longevity, egg load, and lack of host-quality preference in the hyperparasitoid Eurytoma goidanichi Boucek (Hymenoptera: Eurytomidae).

Abstract

The host-quality preference and egg load of the hyperparasitoid Eurytoma goidanichi Boucek (Hymenoptera: Eurytomidae) were investigated under laboratory conditions. E. goidanichi parasitized young and old cocoons of Cotesia glomerata L. (Hymenoptera: Braconidae) without distinction. However, mortality, progeny sex ratio (proportion of males), and developmental period of E. goidanichi laid in old host cocoons were higher and longer than those laid in young host cocoons, indicating that old cocoons were less suitable hosts. Females lived more than 2 months, whereas males lived less than 2 weeks. Few mature eggs were present in the egg reservoir of newly emerged females, but the number increased up to 12 eggs within 5 days. This value was constant for more than a month and then gradually decreased to a few. Young (7 days old) females laid more than 10 eggs per day and old (age 80 days or more) females laid 5 eggs per day, corresponding with the number of mature eggs in the egg reservoir of females of their age. Females laid a similar number of eggs on successive attacks at one or several day intervals, indicating a high ability to produce new eggs. E. goidanichi is synovigenic, and it is thus advantageous to lay eggs immediately on whatever hosts in encounters.