Two new karyotypes in the Chrysolina aurichalcea (Mannerheim) complex (Coleoptera: Chrysomelidae), their relationship and distribution in the Japanese Archipelago

To analyze chromosomal polymorphism in the Chrysolina aurichalcea complex, two new karyotypes were described, and their total complement lengths were compared using their hybrid chromosome. The distribution of the karyotypes, including those studied thus far in the Japanese Archipelago, was surveyed. The new types had chromosome numbers of 2n (male)=31 and 2n (male)=41 and were both XO sex-systems. The 31 type differed markedly from the 41 type and all other types in karyotype. The total complement length of the 31 type was slightly larger than or the same as that of the 41 type. Both types were widely distributed throughout the Japanese Archipelago. The 31 type inhabited most parts of Japan and the 41 type prevailed in Hokkaido, a few islands and mountainous areas in Honshu. Distribution of the two types appeared to be allopatric or parapatric. The geographic distribution of the 41 type is presumed to be a relict type to the 31 type. The relationships between the two types. and between each of the two and the other karyotypes: are discussed in reference to the speed of karyotype differentiation of the two types. Tt is speculated that karyotype differentiation between the two types may have proceeded at a rather high evolutionary rate.