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Annexe III<br />

_____________________________________________<br />

ABSTRACT<br />

Temperature and hydric conditions within the nest on <strong>de</strong>velopment and survival of<br />

embryos and phenotypes of hatchlings has been well documented in ectothermic sauropsids.<br />

Most authors, however, have only consi<strong>de</strong>red constant hydric conditions within the nest, even<br />

though <strong>de</strong>velopmental moisture in natural settings fluctuates consi<strong>de</strong>rably on a daily and<br />

seasonal basis. A laboratory study was performed on 188 eggs from 26 clutches in the re<strong>de</strong>ared<br />

sli<strong>de</strong>r turtle (Trachemys scripta elegans) to <strong>de</strong>termine the effect of hydric variance on<br />

hatching success, incubation length and hatchling mass. We also tested the effect of hydric<br />

condition on survival rate after one year. Eggs were incubated on substrates with 3 different<br />

water potentials (i.e. dry, intermediate and wet) at constant temperature yielding both sexes<br />

(i.e. 28.9 ± 0.1°C). Transfers between substrates were performed every 2 days to mimic<br />

variations of hydric conditions. Hatching success was found to be in<strong>de</strong>pen<strong>de</strong>nt from hydric<br />

conditions but incubation length and hatchling mass were negatively related with time spent<br />

on dry substrate, suggesting that hydric conditions may affect hatchling quality. However,<br />

moisture substrate seems to have a very short-term effect on hatchling phenotype, while<br />

sexual phenotype seems to have a great influence on mass and growth of hatchlings up to one<br />

year.<br />

1

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