Premiers - Outil de Suivi des Contrats

Annexe A
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INTRODUCTION
We propose a new mechanistic model of TSD, which considers physiological processes of
TSD and their interplay with temperature fluctuations during incubation period to predict
embryos sex. The model was built by using several physiological data collected for the
European pond turtle, Emys orbicularis, that is the most studied species as regards to
physiological bases of TSD (Pieau et Dorizzi 1981, Pieau 1982, Pieau et al. 1994, Pieau 1996,
Pieau et al. 1998). We modelled the growth of the embryo, the growth of gonads and the
activity of the feminizing enzyme aromatase, all as direct or indirect functions of incubation
temperature.
METHODS
Model for the growth of the embryo
In poikilotherm species, early mass of the embryo is commonly modeled as varying
exponentially with time of development (Gillooly et al. 2002, West et al. 2004). The general
equation is:
r t
mt () = me m
0
where m 0 is the mass of the embryo at the beginning of incubation period, t is the time of
development and r m the growth rate of the embryo. The growth rate r m of embryo upon time is
itself dependent on the incubation temperature, during all incubation period (Pieau et Dorizzi
1981, Webb et al. 1987).
Based on experiments in other sauropsids, as well as in Emys orbicularis, we know that r m
should be near 0 at very low temperature (