Dietary carotenoid supplementation improves the escape performance of the southern corroboree frog
Nutritional conditions experienced by an individual are known to affect phenotype and performance. In particular, dietary carotenoids influence vertebrate immune function, vision and coloration and have recently been suggested to enhance exercise performance. Despite growing interest in investigating the effect of dietary carotenoids on exercise performance, studies to date have been limited to short-term supplementation during a single life stage. The present study elucidates, for the first time, the effect of long-term carotenoid supplementation during both developmental and adult life stages on the aquatic and terrestrial escape performance of adult southern corroboree frogs, Pseudophryne corroboree, testing the predictions of the 'environmental matching' and the 'silver spoon' hypotheses. Individuals (N = 24 per treatment) were exposed to one of four dietary treatments: (1) both developmental and adult life stages were fed a carotenoid-supplemented diet (C-C); (2) developmental life stage, but not adult life stage, was fed a carotenoid-supplemented diet (C-U); (3) adult life stage, but not developmental life stage, was fed a carotenoid-supplemented diet (U-C); (4) both developmental and adult life stages were fed an unsupplemented diet (U-U). There was no effect of dietary carotenoids on swimming speed, hopping speed or righting ability. However, our results do indicate an effect of carotenoid supplementation on both swimming distance and hopping distance. Frogs receiving a carotenoid-supplemented diet during both developmental and adult life stages consistently outperformed other dietary treatments in the distance travelled during aquatic and terrestrial escape trials. Our results do not show support for either the silver spoon or the environmental matching hypothesis, but indicate an overall benefit of exposure to a carotenoid-rich environment across both life stages.