REPRODUCTIVE-BEHAVIOR OF THE JAPANESE TREEFROG, RHACOPHORUS-ARBOREUS (ANURA, RHACOPHORIDAE)

Reproductive behavior of the foam-nesting treefrog, Rhacophorus arbore us, is described. Oviposition was made either by an amplectant pair (a female and an amplectant male) alone or by an amplectant pair and oth er males (joiners). The snout-vent length of males and females was neg atively correlated with the date of the first appearance in the pond. The period of staying in the pond in males was longer than that in fem ales. Physical body contacts of other males and encounter calls by amp lectant males were frequently observed before oviposition with joiners . Snout-vent length of the female and an amplectant male were positive ly correlated. Encounter calls by amplectant males were likely to prec ede movements of females. There was no difference of snout-vent length between amplectant males and joiners. Females moved the hindlimbs mor e frequently than males during oviposition. Amplectant males made enco unter calls more frequently in oviposition with joiners than ovipositi on without joiners. The patterns of transitions between acts of female s and amplectant males were similar between oviposition with and witho ut joiners. Females more frequently responded to amplectant males than joiners. Both the duration of a bout of the movements of hindlimbs of females and the interval between the bouts were longer in oviposition without joiners than that with joiners. The number of the movements p er bout in oviposition without joiners was smaller than that with join ers. Encounter calls by amplectant males during oviposition tended to precede the hindlimb movements of females.