Comparison of flight ability of Trichogramma brassicae (Hym.: Trichogramatidae) at different generations

The flight and walking activities of the second, forth, sixth and eighth generations of Trichogramm brassicae reared on Sitotroga cerealella eggs were compared under laboratory condition. The parasitoid wasps were obtained by collecting egg masses of Naranga aenescens from rice fields and Sitotroga cerealella egg traps. The experiments of flight and walking activities was carried out using black P.V.C. tubes and the percentage of inactive, flying and walking wasps to light were calculated. Results showed a reduced flight and walking activities and increased percentage of inactive wasps with the increasing number of generations. In second generation, 41.9±2.88, and 36.7±2.65 of wasps population had flight, and walking ability, respectively, and 21.4±2.45 of them was not able to fly and walking. The highest percentage of inactive wasps were observed at eighth generation, whereas wasps showed significantly better flight and walking activities at second generation. Based on the results, flight and walking abilitiies of T. brassicae were gradually decreased at continuous laboratory rearing.