INFLUENCES OF WILD CRUCIFERS ON LIFE-HISTORY TRAITS AND FLIGHT ABILITY OF THE DIAMONDBACK MOTH, PLUTELLA-XYLOSTELLA (LEPIDOPTERA, YPONOMEUTIDAE)

The larvae of Plutella xylostella were fed on five wild crucifers, Cap sella bursa-pastoris, Lepidium virginicum, Cardamine flexuosa, Rorippa indica, R. islandica and a crop, cabbage. The developmental period of the immature stages, adult longevity, preoviposition period, fecundit y and morphometrical characters of the adults were measured. The fligh t activity of the adults was also measured by the tethered flight meth od. All the wild plants except for R. islandica were less suitable hos t plants than cabbage, and larvae which were fed on these less suitabl e plants emerged as smaller adults with shorter wings. The smaller fem ale adults had lower fecundity but a higher flight activity. Smaller a dults measured in terms of their pupal weight among individuals fed on the same host plant had longer wings. These smaller adults with longe r wing flew more actively.