Abstract
Chemical analyses were conducted of male scent of Pieris napi collected in two districts, Yamaguchi Prefecture and Hokkaido. The androconial secretion of most individuals of Yamaguchi population comprised well-known compounds, linalool, nerol, neral and geranial, whereas some other males were found to secrete different and as yet unidentified monoterpenic components. We designate the former as Type I, and the latter, Type II. Further investigation on Hokkaido population revealed that it is of Type II. These findings are suggestive of the presence of at least two strains of P. napi of which male androconial secretion is chemically polymorphic.
