Meeting Abstract

P1.156  Wednesday, Jan. 4  Carry-over effects of pond canopy cover on locomotor performance of the American toad ( Anaxyrus americanus ) CHARBONNIER, J.F.*; GERALD, G; PURRENHAGE, J; SCHAEFFER, P; Virginia Commonwealth University, Richmond; Nebraska Wesleyan University, Lincoln; University of New Hampshire, Durham; Miami University of Ohio, Oxford

Animals with complex life cycles pass through one or more ecologically distinct phases during ontogeny. These life stages are highly interconnected and conditions experienced during one life stage may influence size, locomotor performance, and physiology in later life stages. Since many pond-breeding species must disperse to suitable terrestrial habitat following metamorphosis, identifying how larval experience impacts locomotor performance of juveniles is important. Larvae from open and closed canopy pond experience different environmental conditions (e.g. light, temperature, dissolved oxygen) which may affect subsequent performance in later life stages. To investigate the potential carry-over effects of canopy cover on locomotor performance we raised American toad (Anaxyrus americanus) larvae in open and closed canopy pond mesocosms. We retained 40 metamorphs from each treatment for speed and endurance trials. We also examined citrate synthase activity of hindlimb skeletal muscle to estimate the proportion of endurance vs. speed type muscle. We found that toads from closed-canopy ponds were 63% heavier and had higher absolute endurance and speed. Toads from open-canopy pond had higher endurance relative to their body size, despite having lower citrate synthase activity. Since citrate synthase activity cannot explain the relatively higher endurance of open-canopy toads, another mechanism is likely involved in the differential performance. Our results demonstrate that the larval environment may impact multiple components of locomotor performance in complex ways.