Comparative analysis of the reproductive attributes of three commercially-produced Trichogramma species (Hymenoptera : trichogrammatidae)

The reproductive attributes of commercially-produced Trichogramma platneri, T. minutum and T. pretiosum reared from eggs of both Ephestia kuehniella a nd Sitotroga cerealella were monitored at 25 degrees C. The age-specific fe cundity, longevity and progeny sex ratio and adult size were determined for individual females from all six combinations of Trichogramma and rearing h ost, using E. kuehniella as the experimental host. Rearing host herd a sign ificant influence on the lifetime fecundity, 3-day fecundity and longevity of all three Trichogramma species. In general, the performance of T. minutu m and T. pretiosum was better when reared from S. cerealella, bur that of T . platneri was superior when reared from E. kuehniella. The lifetime fecund ity of the Trichogramma species was linearly related to longevity and the r anking between species was T. pretiosum>T. minutum>T. platneri. The age-spe cific pattern of oviposition for T. platneri was distinctly precocious, wit h 40% of its lifetime fecundity oviposited on the first day, in contrast to 17-24% for the other two species. Progeny sex ratio over the lifetime of t he Trichogramma females was slightly male biased and differed significantly from 0.5 for T. minutum and T. platneri. Daily sex ratio for parasitoids r eared from the most productive rearing host was female biased only for the first day of oviposition for T. platneri in contrast to the first 5-6 days of oviposition for the other two species. There was little evidence that an y of the reproductive attributes of these Trichogramma species, reared from small host eggs, was dependent on the size of the adult females.