Water balance and nitrogen excretion of two introduced frogs (Litoria raniformis and l. ewingi)

Abstract

Rates of dehydration, rehydration and hydrated water uptake were measured in the hylid frogs Litoria raniformis and L. ewingi. The more terrestrial L. ewingi generally has a lower rate of dehydration caused by the adoption of a more water-conserving posture and reduced activity. Both species show a well developed water balance response (rapid rehydration) and ventral skin appears specialised for rapid water uptake.The predominant form of excreted nitrogen changes during development in the two species. The aquatic tadpoles are ammonotelic and metamorphosed frogs strongly ureotelic. Diet appears to have a large effect on absolute (but not relative) levels of ammonia and urea nitrogen excreted by metamorphosed L. raniformis.Despite its semi-aquatic habitat, L. raniformis displays some features (rapid rehydration and strong ureotelism) characteristic of a more terrestrial existence. © 1985 Taylor & Francis Group, LLC.