B chromosomes, translocation between B and autosomes, and C-heterochromatin polymorphism of the grasshopper Podisma sapporensis Shir. (Orthoptera, Acrididae) in Hokkaido, Northern Japan

Seven categories of B chromosomes found in the brachypterus grasshopper Pod isma sapporensis from Hokkaido populations differ in structure, size, and C -band content. The interchange between B and one autosome from M-3 and spor adically M-7 was observed in most of the populations examined. Such an inte raction between standard and non-standard chromosomal set provides an insig ht into the integration of supernumerary chromosome. In addition, C-hrteroc hromatin polymorphism was also identified in male karyotypes in some popula tions. These facts indicate P. sapporensis is a highly polymorphic species from the cytogenetic point of view.