The effect of wing size and wing shape on field fitness of mass reared Trichogramma pretiosum, Trichogramma near brassicae, and Trichogramma brassicae were investigated. Wasps were released in the field and those females ovipositing on eggs of the target pest were recaptured. Comparisons of the recaptured group with a sample from the release population were used to assess fitness. For the field experiment with T. brassicae an additional aspect was added by evaluating how wing attributes of recaptured wasps change with distance from the release point and time since release. Wing data were obtained by positioning landmarks on forewings. Wing size was calculated as centroid size based on interlandmark distances, and wing shape using Procrustes superimposition. The results showed that T. pretiosum and T. nr. brassicae wasps successful in the field had larger wings and different wing shapes compared to wasps from the release population. Both size and shape dimensions were linearly associated with fitness. For T. brassicae, wing size increased with recapture distance from the release point, however wing size decreased with time since release. In contrast to the findings above, no effect of wing shape on field fitness was detected for T. brassicae, indicating that wing shape related fitness effects may be species specific. The findings indicate that wing size may be an accurate predictor of field fitness in these Trichogramma wasps, but the effect of wing size on dispersal distance and time has to be taken into consideration when using this trait.
Species 1: Hymenoptera Trichogrammatidae Trichogramma pretiosum
Species 2: Hymenoptera Trichogrammatidae Trichogramma near brassicae
Species 3: Hymenoptera Trichogrammatidae Trichogramma brassicae
Keywords: Mass rearing, quality control
Back to Student Competition Ten-Minute Papers, Subsection Ca1. Biological Control
Back to Student Competition 10-minute Paper
Back to The 2002 ESA Annual Meeting and Exhibition