Proximate and Ultimate Factors underpinning Biennial Reproduction in the Pig-nosed Turtle, Catettochelys insculpta.

In many ectotherms, females reproduce biennially due to limited energy acquisition. Two competing hypotheses have been proposed to explain biennial breeding; on involving a genetic basis for reproductive frequency and another simply involving phenotypic plasticity. In the proposed study we will indirectly test these competing hypotheses for biennial reproduction in the turtle Carettochelys insculpta by comparing field energetics and reproduction of two populations; one that is energy limited and anothe that is not. No study has attempted to directly test these hypotheses, and this study will provide the first data on food and energy intake in an aquatic turtle.