Meeting Abstract

P2.53  Sunday, Jan. 5 15:30  Compensatory growth in larval American Toads YOUNG, R*; PERRY, SL; JENNINGS, KX; RODRIGUEZ, WB; BOUCHARD, SS; Otterbein Univ., Westerville OH; Otterbein Univ., Westerville OH; Otterbein Univ., Westerville OH; Otterbein Univ., Westerville OH; Otterbein Univ, Westerville OH sbouchard@otterbein.edu

Juvenile growth rate is an important life history trait that is linked to adult fitness in many organisms. After a period of limited resources, some organisms experience accelerated growth rates that allow them to compensate for periods of slow growth. For animals with complex life cycles, such compensatory growth could have carry over effects for future life stages. We assessed the capacity for compensatory growth in larval American Toads, Bufo americanus, and investigated effects on growth post-metamorphosis. Larvae were reared at high, medium and low densities in 410 L mesocosms. Each mesocosm was supplied with equal food rations, such that per capita food availability varied with density. Upon reaching an average mass of 1.3 g, a subset of larvae were removed from their initial densities and placed at low densities with high food availability. One week growth rates, as well as time to and size at metamorphosis were determined. Post-metamorphic growth rates were also measured for toadlets maintained in the lab on a fruit fly diet for five weeks. Initially, larvae did not demonstrate compensatory growth as one week growth rates of larvae from medium and high densities were lower than those of larvae from the low density. However, larvae from the medium density metamorphosed sooner than and at the same size as those from the low density. Larvae from the high density were slightly smaller and metamorphosed at the same time as those from the low density. There were no significant differences in post-metamorphic growth rates. These results suggest that the capacity for compensatory growth may vary with initial food restriction levels.