抄録
The role of visual and chemical cues of conspecifics in the growth of head width was experimentally tested in Hynobius retardatus larvae reared under group and solitary conditions. In the former, the head width of the larvae increased proportionally in the presence of visual, chemical, and visual plus chemical cues, whereas such a morphological change was not apparent with similar cue treatments in solitary larvae. It was concluded that both visual and chemical cues from other conspecific individuals induced the wider head shape in H. retardatus larvae.