Abstract
The study of energy allocation is essential in understanding the regulation of major life history traits. It is often assumed automatically that the limitation of an energy budget or higher allocation to a single trait afect all life history traits.
This assumption was inher- ently included in infuential models of ontogenetic growth. We aim to challenge this per- spective by focusing on growth in lizards.
Summarizing the results of a series of long-term manipulative experiments in the Madagascar ground gecko (Paroedura picta), we show that although growth is generally assumed to be highly plastic in reptiles and other ecto- thermic vertebrates, it is at least in this species largely canalized and does not seem to be afected by energy limitations under several experimental conditions. Diet restriction, resulting in lower allocation to fat storage and reproduction, and the allocation to energeti- cally demanding traits such as reproduction in both sexes and tail regeneration had little if any efect on structural growth.
We document that sexual size dimorphism does not emerge in the ontogeny of the studied species directly due to diferential allocation to structural growth in males and females. Instead, sex-specifc growth trajectories are driven by a sign- aling of ovarian hormones as the key proximate mechanism shaping sex-specifc allocation decisions during ontogeny.
We suggest that the large degree of canalization of the struc- tural growth can refect hierarchy in energy allocation with the structural growth being prioritized to investment in other traits. The prioritized allocation to structural growth can refect selective advantage of reaching a fnal, optimal size for a given sex as fast as possible.