The change of the distribution pattern of the large weevil,Hyposipalus gigas Fabricius (Coleoptera, Rhynchophoridae) within a single generation. A preliminary note

Summary

The distribution pattern of adults of the large weevil,Hyposipalus gigas on logs of the Japanese black pine and that of larvae in pine stumps were examined by using them ^*−m method (Iwao, 1968). The distribution of adults on logs was contagious, probably due to their response to local heterogeneity of the environment. The larval distribution was also contagious, but there was no significant correlation between the number of larval bores and the stump size. The mortality of young larvae seemed not to be related with the number of larvae per stump, but it was related with the density per unit area of bark surface. There was some sign of inversely density-dependent or ‘all-or-none’ type mortaltiy in the late larval stage.