The trade‐off between maturation and growth during accelerated vertebrate development

Abstract

Developmental energetics are crucial to a species’ life history but are poorly understood mechanistically. Traditional energy and mass budgeting does not distinguish between costs of growth and maturation, making it difficult to account for accelerated development. We apply Dynamic Energy Budget theory (DEB), which exclusively considers maturation costs, to interpret empirical data on the energetics of development through metamorphosis in two related frogs, Crinia georgiana and Pseudophryne bibronii. Dry mass (2.74 in C. georgiana, 2.68 mg in P. bibronii) and energy content (70 and 65 J) of fresh ova were similar between the species. However, development to metamorphosis was 1.7 times faster in C. georgiana while P. bibronii produced nine times the dry mass at metamorphosis. DEB theory explains these differing patterns through a trade‐off in ontogenetic energy allocation between maturation and growth. P. bibronii partitioned energy in a constant fraction (0.31) throughout development whereas C. georgiana increased the fraction (0.14 to 0.39) of energy allocated to maturation over growth between hatch and the onset of feeding. The change in developmental energy allocation in C. georgiana may result from a selective pressure to increase development rate. Funding from the University of Adelaide.