Dispersal polymorphism in the diamondback moth, Plutella xyllostella grown on different host plants, and its ecological significance

点击翻译按钮获取中文摘要

The wild crucifers, Rorippa indica and Lepidium virginicum, are known to serve as host plants for the diamondback moth (DBM), Plutella xylostella, but they are less suitable than the preferred cultivated cruciferous plant, cabbage, in terms of adult body size and fecundity. The life history traits and flight activity of DBM adults grown on various host plnts were investigated. In general, female adults grown on the wild crucifers were less fecund and lived longer than those reared on cabbage. Flight activity was higher in adults grown on wild crucifers than in those reared on cabbage. Male adults flew longer than females. Fecundity, longevity, flight activity and morphometrical characters of adults were positively correlated with pupal weight in individuals reared on the same host plant. A negative relationship was found between fecundity and flight activity in females of the same size group grown on different host plants, but a positive one was observed in different sized females reared on the same host plant. The amounts of glycerides tended to be higher in teh adults grown on R.indica than in those grown on cabbage. The amounts of other nutrients, glycogen, total sugars and free amino acids tended to be lower in the adults grown on R.indica than in those grown on cabbage. These facts suggest that larval host plants influence nutrient allocation between flight fuel and egg production in the DBM.Changes in the ability of the DBM to habituate to wild host plants, R.indica and cabbage for four generetions were examined. For both habituated lines, R.indica and cabbage, the developmental period of R.indica line was shorter than that of cabbage line. The fecundity of female adults was not different between R.indica and cabbage lines. This fact suggests that the DBM of R.indica line have habituated in some degree to R.indica.