Reproductive ecology of Sichuan digging frogs (Microhylidae: <em>Kaloula rugifera</em>)

Abstract

Abstract. We investigated the reproductive ecology of Sichuan digging frogs (Microhylidae: Kaloula rugifera) in Mianyang, China during the wet season of 2013. Male Sichuan digging frogs first appear at temporary ponds following the first heavy rain of the wet season and initiate calling. Females arrive at ponds shortly after males. Male frogs chorus extensively throughout the wet season during the evenings and nights following rainstorms. Female frogs leave the pond after laying eggs, and likely only lay one clutch annually. Amplexus lasted up to three hours. Females were larger than males in terms of body size, but we found no evidence of size-assortative mating. Clutch size varied from 920 to 2200 eggs, with egg diameter ranging from 1.33 to 1.93 mm. Larger female frogs laid more eggs, and there was no correlation between egg number and egg size. Tadpoles hatched from eggs within 18-20 hours of oviposition, and grew for 30-40 days before complete metamorphosis occurred. The initial body length of tadpoles ranged from 3-5 mm snout-vent length. Growth was fastest immediately after hatching, and declined asymptotically with increasing tadpole body size. Overall, Sichuan digging frogs have a breeding biology characterized by strong male-male competition with prolonged breeding coinciding with the annual wet season.

Keywords. Breeding ecology; Kaloula rugifera; life history; mating system