Air and water differ dramatically in density and viscosity, posing different biomechanical challenges for animal locomotion. We asked how terrestrial acclimation influences locomotion in amphibious fish, specifically testing the hypothesis that terrestrial tail flip performance is improved by plastic changes in the skeletal muscle. Mangrove rivulus Kryptolebias marmoratus, which remain largely inactive out of water, were exposed to water or air for 14 days and a subgroup of air-exposed fish was also recovered in water. Tail flip jumping performance on land improved dramatically in air-acclimated fish, they had lower lactate levels compared with control fish, and these effects were mostly reversible. Muscle plasticity significantly increased oxidative muscle cross-sectional area and fibre size, as well as the number of capillaries per fibre. Our results show that reversible changes to the oxidative skeletal muscle of K. marmoratus out of water enhance terrestrial locomotory performance, even in the absence of exercise training.
The authors declare no competing or financial interests.
E.M.B., A.J.T. and P.A.W. conceived and designed the project. E.M.B. executed the experiments and analysed the data. A.J.T. and G.R.S. assisted with histological procedures. E.M.B. and P.A.W. wrote the draft manuscript. E.M.B., A.J.T., G.R.S. and P.A.W. revised the manuscript.
Funding was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grants program to P.A.W. (120513) and an NSERC graduate scholarship to A.J.T.
- Received March 25, 2016.
- Accepted August 14, 2016.
- © 2016. Published by The Company of Biologists Ltd