Abstract:

Relationships between female body size, egg load and fecundity of Trichogramma ostriniae Pang et Chen were analyzed through dissecting ovaries at different ages (0－144 h) of female wasps. The results showed that only a fraction of mature eggs were observed in ovaries at the early stage after emergence, however, egg load increased as the female age increased and almost corresponded to ovary storage capacity by 72 h of adult life. The dependence of egg load on age could be well described by the formula, y=a｛1-exp［-b(x+c)］｝. Female wasps with hind tibia length (HTL) shorter than 0.150 mm, between 0.150－0.159 mm and longer than 0.160 mm produced 40.4, 50.5 and 58.2 eggs in 24 h after emergence, respectively, accounting for 72.8%, 79.3% and 86.9% to their respective ovary storage capacity, corresponding to 49.4%, 47.9% and 51.9% of their respective total lifetime egg complement in the presence of unlimited hosts. On the first day of oviposition, the mean number of eggs laid was fairly close to the egg load. There was a significant positive linear relationship between egg load and female body size of T. ostriniae, so was between the female body size and lifetime fecundity.

Key words: Trichogramma ostriniae, female age, female body size, egg load, fecundity