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Annexe III
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and metabolism, incubation length, embryos survival and hatching success (Morris et al.,
1983; Gettinger, Paukstis & Gutzke, 1984; Packard, 1991a; Packard et al., 1991b; Miller &
Packard, 1992; Janzen et al., 1995; Tucker, Janzen & Paukstis, 1997; Tucker et al., 1998;
Packard, 1999a; Tucker & Paukstis, 2000; Rimkus, Hruska & Ackerman, 2002; Nakage et
al., 2003). The water potential is also found to have long-term effects on locomotor
performance, size, growth and survival of hatchlings (Gutzke & Packard, 1986; Finkler, 1999;
Packard et al., 1999b; Finkler, 2001; Ji & Du, 2001; Packard & Packard, 2001). However,
other authors refute these effects of water potential (Tracy, 1980; Janzen et al., 1995; Ji &
Brana, 1999; Ji et al., 2001; Booth, 2002; Filoramo & Janzen, 2002; Marco et al., 2004). The
study of water potential effects may thus be crucial to understand the pattern of selection on
life-history traits, susceptible to influence individual fitness. It may also be crucial in
conservation biology, because effects of water potential on incubation length, hatching
success and hatchling phenotype partly determine the conditions in which an introduced
species can become invasive in a new environment.
Millions of juveniles of the red-eared slider turtle (Trachemys scripta elegans), native to
United States, was sold as pet in France between 1970 and 1997. After few years, turtles
became adult, and most of them were released by owners in natural ponds. In the present
study, we examined potential influence of hydric conditions within the nest on colonization
capacities of this species. We examined the role of moisture substrate on hatching success,
incubation length and hatchlings condition in this turtle that lays flexible-shelled eggs. We
also examined the influence of different treatments with fluctuating water potential and
individual characteristics (maternal identity, initial egg size) on change in eggs mass during
different periods of incubation time, independently of incubation temperature. Finally, results
were interpreted in an ecological and evolutionary context.
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