Inability of adult Limnodynastes peronii (Amphibia : Anura) to thermally acclimate locomotor performance

Despite several studies on adult amphibians, only larvae of the striped mar sh frog (Limnodynastes peronii) have been reported to possess the ability t o compensate for the effects of cool temperature on locomotor performance b y thermal acclimation. In this study, we investigated whether this thermal acclimatory ability is shared by adult L. peronii. We exposed adult L. pero nii to either 18 or 30 degrees C for 8 weeks and tested their swimming and jumping performance at six temperatures between 8 and 35 degrees C. Acute c hanges in temperature affected both maximum swimming and jumping performanc e, however there was no difference between the two treatment groups in loco motor performance between 8 and 30 degrees C. Maximum swimming velocity of both groups increased from 0.62 +/- 0.02 at 8 degrees C to 1.02 +/- 0.03 m s(-1) at 30 degrees C, while maximum jump distance increased from similar t o 20 to > 60 cm over the same temperature range. Although adult L. peronii acclimated to 18 degrees C failed to produce a locomotor response at 35 deg rees C, this most likely reflected a change in thermal tolerance limits wit h acclimation rather than modifications in the locomotor system. As all adu lt amphibians studied to date are incapable of thermally acclimating locomo tor performance, including adults of L. peronii, this acclimatory capacity appears to be absent from the adult stage of development. (C) 2000 Elsevier Science Inc. All rights reserved.