GEOGRAPHIC-VARIATION IN THE INCIDENCE OF NON-DIAPAUSE EGGS OF THE FALSE MELON BEETLE, ATRACHYA-MENETRIESI FALDERMANN (COLEOPTERA, CHRYSOMELIDAE)

Geographic variation in the incidence of non-diapause eggs of Atrachya menetriesi was investigated in the Japanese islands. Most eggs entered diapause throughout the whole range of distribution in Japan. A few eggs, however, hatched without any arrest. The proportion of non-diapause eggs increased from north to south, the maximum being about 15%. A high positive correlation was found between the percentage non-diapause and the annual mean temperature. In the field, larvae and adults of a partial 2nd generation were found frequently in the south but rarely in the north. The latitudinal variation in the incidence of non-diapause was also found among the local populations reared in the laboratory under identical conditions. It seems therefore that the geographic variation is due to the genetic divergence rather than the direct effect of different local environmental conditions. © 1979, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.