Meeting Abstract

P2.84  Saturday, Jan. 5  Carryover effects of larval density on body composition, growth, and feeding in Gray Treefrogs, Hyla versicolor, post-metamorphosis. WARGELIN, LJ*; MASSEY, K; BOWLING, M; YOUNG, RS; BOUCHARD, SS; Otterbein University; Otterbein University; Otterbein University; Otterbein University; Otterbein University sbouchard@otterbein.edu

Amphibian larval environments can have important effects on individuals post-metamorphosis. We studied the effects of larval density on froglet condition, growth and feeding in Gray Treefrogs, Hyla versicolor. Larvae were reared at high, medium and low densities in 410 L mesocosms. Each mesocosm was supplied with the same amount of algal food, such that food availability varied with treatment. Larvae were photographed and measured with image analysis software to determine growth rates. Upon emergence from mesocosms, froglets were weighed and measured. They were either euthanized for percent dry matter and ash determinations or placed in individual aquaria where they were maintained on insects to investigate feeding and growth. Euthanized froglets were dried at 65 °C and then ashed at 500 °C. All feces were collected for two weeks from maintained froglets, and intake was determined by counting insect head capsules in feces. Larvae reared at high densities grew significantly slower and metamorphosed later than those reared at low densities. Froglets emerging from high larval densities were one third the mass of those emerging from low densities. Their bodies were also significantly lower in percent dry matter (11.5 vs. 14.3 %) and percent ash (78.3 vs. 83.8 %). High density froglets began producing feces 3.5 days later than low-density froglets (8.1 vs. 4.7 days). However, high-density froglets grew by 58% during the four weeks post-metamorphosis, whereas low-density froglets did not grow appreciably. These results suggest that while low larval food resources initially reduce froglet quality, froglets may maintain the capacity to compensate with accelerated growth post-metamorphosis.