On the colour polymorphism in Chrysolina aurichalcea (Mannerheim) (Coleoptera : Chrysomelidae) collected from four mountain districts.

The adults of Chrysolina aurichalcea were collected from four mountain districts to examine the relationship between adult colour polymorphism and altitude. The ratio of two colour forms was found to change with altitude. The cupreous-form dominated at high altitude, while the cyaneus-form dominated at low altitude. Detailed collections at the Utsukushigahara Heights and in their vicinity showed that the reducing proportion of the cyaneus-form did not occur gradually with increasing altitude but did so abruptly at a precise altitude for each site. This altitude was different for the south slope and the west slope. The increase in the percentage of the cupreous-form at high altitude is discussed in relation to three possible explanations.Article信州大学理学部紀要 14(2): 99-106(1980)departmental bulletin pape

Multiple matings of Chysolina aurichalcea (Mannerheim) (Coleoptera : Chrysomelidae)

The existence of multiple matings in both males and females of a chrysomelid beetle Chrysolina aurichalcea was examined by measuring the total duration of copulation in one multiple-mating bout and by observing the caged population every two hours for six days. The mean total duration of copulation in one multiple-mating bout was 3.2±1.7 hrs under a plastic container. Observation for six days showed that all five females conducted an average of seven matings with three males. In case of all five males, an average of nine matings with four females were observed except two males which had performed no copulations. The significance of multiple matings of the species was discussed in relation to the effects of selection pressure on genetic variations of discreet populations.Article信州大学理学部紀要 21(1): 23-30(1986)departmental bulletin pape

The genetics of two colour forms of Chrysolina aurichalcea (Mannerheim) (Coleoptera: Chrysomelidae) and these gene frequencies around the Utsukushigahara Heights, central Honshu, Japan.

The inheritance pattern of the two colour forms (cyaneus-form and cupreous-form) of adult Chrysolina aurichalcea (Mannerheim) was examined by the crossing. The inheritance of these colour forms followed Mendel's law, showing the dominance of cyaneus-form over cupreous-form. The sampling of field populations around the Utsukushigahara Heights, central Honshu, Japan, was carried out at 74 sites. The estimation based on these results showed that the gene frequencies of cupreous-form were high (80-90%) at mountain areas (the sites higher than alt. 1600m) whereas they were low (20-50%) at the basins of both sides of the heights (the Matsumoto and the Ueda basins: the sites lower than alt. 800m). At the boundary of the mountain areas and the two basin areas, the gene frequency showed various rate and in some cases, it changed abruptly between the two sites which were apart from each other by a few hundreds meters. The histogram of gene frequencies among them for 8 years showed that the frequencies were fairly constant at major sites. At some sites, the phenotypic frequency of cupreous-form fluctuated very much. The causes of differentiation into two groups and of the change at some sites in phenotypic frequency were discussed with possible explanations, especially in relation to natural selection by the environmental factors.Article信州大学理学部紀要 22(2): 83-97(1987)departmental bulletin pape