Meeting Abstract

P3.115  Friday, Jan. 6  Metabolic carryover effects in postmetamorphic red-eyed treefrogs WARGELIN, L.W.*; BOUCHARD, S.S.; WARKENTIN, K.M.; Otterbein University; Otterbein University; Boston University

Resource availability has a strong effect on growth and development. Low food levels reduce larval growth rates and, in anurans, can delay metamorphosis dramatically. There may also be important metabolic implications, as some animals respond to low resource availability with reduced metabolic rates. Such effects could have long term impacts if larval metabolic adjustments persist post-metamorphosis. We assessed the effect of different competitive environments on metabolic rates of postmetamorphic red-eyed treefrogs. We reared larvae at high, medium, and low densities (5, 25 and 45 per 400 L), providing each tank with equal food levels so per capita resources were lower in high density mesocosms. We assessed larval growth rate by photographing larvae at two time points and measuring length with image analysis software. We later collected and measured metamorphosing individuals as they emerged from the water. Once metamorphosis was complete, we assessed metabolic rates by measuring oxygen consumption in a closed-system respirometer. Low-density larvae grew four times faster and began emerging over two weeks earlier than high-density larvae. Froglets generated from low-density environments were also three times heavier than those from high-density environments. We measured oxygen consumption of individuals ranging in size from 0.33 – 0.99 g. Overall, metabolic rate scaled with body mass with an allometric slope of 0.97. This slope is greater than that reported for other anurans, and suggests that metabolic rates of smaller high-density froglets could be depressed relative to larger low-density froglets. Such an effect could arise due to changes in organ size occurring during the larval period and carrying over post-metamorphosis.