2016 Volume 67 Issue 2 Pages 41-57
The taxonomy of the Pieris napi complex in Japan, especially in Hokkaido, has been under dispute since Shirôzu (2002, 2006). In these works, two closely similar napi groups, i.e., dulcinea in the Doutou area (Eastern Hokkaido) and nesis in the Dounan area (Southern Hokkaido), were treated as different species based on the mtDNA molecular phylogenetic study (Fujii et al., 2001). It is very difficult to distinguish the two species by their wing shapes and markings, or even by microscopic observation of the androconia. Moreover these two groups easily mate to produce viable offspring in indoor experiments (Kuroda, 2008), so Uemura (2014) treated them as the same species napi. In this paper, I examined morphological variations among the spring form of three Pieris species in Hokkaido, i.e., two napi complex species and P. melete comparing them with the “type specimen” of P. napi nesis Fruhstorfer in the Natural History Museum, London (NHM). Twenty variables, which can be designated by details of wing outlines and vein line distance and degree, were examined. The plot charts of the variables suggest that nesis male and female belong to the napi group of the Doutou area. The Kruskal-Wallis tests, Steel-Dwass tests and principal component analysis confirm the above suggestion and that the two close napi group species are clearly divided in the scatter plot. The type locality P. napi nesis Fruhstorfer was not inferred to be “Nord Hondo” as Eitschberger (1983) indicated, but to be “Sapporo”(Hokkaido) as stated in the original description (1909). P. nesis should be recognized as a population of the napi group from the Doutou area and not the Dounan area or the Hondo group.
