Reproductive patterns of two sympatric rhacophorid frogs, Buergeria japonica and B. robusta, with comments on anuran breeding seasons in Taiwan

Abstract

Present study tested a hypothesis that the seasonal reproductive pattern would be similar between two sympatric congeneric species of frogs, Buergeria japonica and B. robusta, by examining, fat body, liver and gonadal cycle. In total, 132 and 148 adult frogs, respectively, were collected from Taichung, Central Taiwan during July 1996 and July 1997. Both species were classified as prolonged breeders, breeding from March to August. This breeding season differs from those in conspecific populations from other localities. In both species, adult females attained larger snout-vent length (SVL), body mass (BM), head length (HL), and head width (HW) than males. The smaller size of male in these species is inconsistent with a previous energetic constraint hypothesis that smaller males are caused by the costs of advertising, maintaining territories, and lower food intake in prolonged breeding species. Neither B. japonica nor B. robusta showed a significant positive correlation between female ovary mass and female SVL, indicating that fecundity selection does not directly affect female body size. Also, timing of reproduction in three other anurans from the present study site is also discussed.