Hybridization and introgression of the two strains of Hokkaikdo gypsy moths as invasions by alien species

Abstract

Male-killing refers to the death of male embryos or larvae, and is well known in a variety of organisms, such as plants, mites, and insects (Hurst et al. 1997). We have found male-killing by about 10 percent females in a Bibai, Hokkaido, Japan, population of the gypsy moth, Lymantria dispar L., and have found maternal inheritance of the trait (Higashiura et al. 1999). These male-killing females have no cytoplasmic bacterial symbionts, which have been found in many male-killing organisms (Hurst et al. 1997). Male-killing and mitochondrial DNA (mtDNA) are both maternally inherited (Schulenburg et al. 2002). The mtDNA haplotypes of the male-killing gypsy moth in Hokkaido are different from Hokkaido types, and is the same as that distributed widely in Asia (Bogdanowicz et al. 2000), including Tokyo. Goldschmidt obtained all female broods by means of backcrossing, i.e. F₁ females of a cross between Tokyo females (subspecies japonica) and Hokkaido males (subspecies praeterea) mated with Hokkaido males (Goldschmidt 1930). We got all-female broods by the double check of Goldschmidt?s results. Moreover we found that male-killing females in Hokkaido mated with Asian type males produced normal sex ratio broods just as Goldschmidt?s theory of sex determination states (Goldschmidt 1934). Therefore all-female broods (or male-killing females) found in Bibai, Hokkaido, are thought as an invasive alien species, because those females have Honshu and Asian types of mtDNA haplotype.

Parent Publication

• Proceedings, 17th U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2006

Citation

Higashiura, Yasutomo; Ishihara, Michio; Yamaguchi, Hirofumi; Ono, Nanako; Tokishita, Shin-ichi; Yamagata, Hideo; Fukatsu, Takema. 2007. Hybridization and introgression of the two strains of Hokkaikdo gypsy moths as invasions by alien species. In: Gottschalk, Kurt W., ed. Proceedings, 17th U.S. Department of Agriculture interagency research forum on gypsy moth and other invasive species 2006; Gen. Tech. Rep. NRS-P-10. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 51-52.