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Leader: Dr. Sylvain Giroud


In fluctuating environments, the timing of reproduction is key for the reproductive success and survival of animal species. It is important that periods of gestation, birth and development of juveniles match optimal food availability in order to maximize chances of survival.

During summer time, the decline of ambient temperatures and food availability combined to poor food quality can overlap with the requirements for growth and development of juveniles. This is particularly observed in late-breeders, i.e. species reproducing and giving birth late in the reproductive season.

In the context of global changes, the availability and the quality of trophic resources, in environments already fluctuating, are largely affected by unpredictable climatic events, whose frequency and intensity keeps increasing. Hence, it appears crucial to determine and characterize the phenotypic plasticity of the physiological responses of animal species, in particular during their early life stages, as well as the ecological and evolutionary consequences of such strategies, in response to large and rapid environmental changes. In that regard, heterothermic species are particularly good models to study these adaptations, since juvenile heterotherms have to ensure both their growth and pre-hibernation fattening to survive their first winter already in hibernation.

This research program is oriented along two major axes:

  1. the ontogenesis of energy-saving strategies of juvenile heterotherms, and
  2. the processes of growth and development, according to the timing of reproduction and food availability and quality.

Within each axis, we aim to determine the physiological and behavioral mechanisms (from the whole-body level to the molecule), as well as the ecological and evolutionary consequences (from the individual to the population) of the phenotypic plasticity during early life stages. Specifically, energy-saving strategies conferring the highest flexibility to the individuals are likely to be conserved and spread among the populations.