Impact de l'humidité ambiante et de l'état hydrique de la plante hôte sur le développement et les traits adultes du papillon "Lasiommata megera"
Files
DeRidder_21242000_2026.pdf
Closed access - Adobe PDF
- 1.9 MB
Details
- Supervisors
- Faculty
- Degree label
- Abstract
- Climate change leads to an increase in global temperatures and in the frequency of extreme weather events, such as droughts. These events directly affect insects, whose water balance can be threatened under dry conditions. Due to their small size and high surface-area-to-volume ratio, insects are particularly sensitive to variations in temperature and humidity. They are directly exposed to their immediate microclimate, which is influenced by the structure and physiological state of vegetation, the vegetation itself being able to act as a refuge by locally modulating thermal and hydric conditions. However, this microclimate remains dependent on macroclimatic conditions, and this buffering capacity may therefore be limited under extreme environmental constraints. Furthermore, insects undergo several developmental stages throughout their life cycle, each of which is subject to specific environmental constraints and may differ in its sensitivity and response to environmental stress. In this master’s thesis, we investigated the effects of water stress on development and adult traits in a butterfly species from open habitats, Lasiommata megera. Water stress was addressed at two spatial scales: a macroclimatic treatment, with drier or more humid conditions in the rearing rooms, and a plant-level treatment, comparing hydrated and dehydrated host plants. We hypothesised that drought would affect individual growth and development, and that larval developmental conditions would have consequences for mass allocation and adult water status. Our results indicate that, within the context of this study, macroclimatic conditions and, to a lesser extent, microclimatic conditions associated with host plants, influence larval growth, emergence dynamics and several traits expressed at the adult stage, with effects depending on the trait considered. Sex-specific responses to water stress were also observed, including changes in mass allocation in females and differences in adult water status between sexes, indicating distinct response strategies in males and females. Despite certain limitations, these results highlight the importance of considering all life stages, while taking into account sex-specific responses and the influence of developmental conditions on traits expressed at the adult stage.