par Zakrzewski, Sara 
Président du jury Dahdouh-Guebas, Farid
Promoteur HERREL, Anthony
Publication Non publié, 2022-08-30
Président du jury Dahdouh-Guebas, Farid
Promoteur HERREL, Anthony
Publication Non publié, 2022-08-30
Mémoire
| Résumé : | In novel environments, invasive species face new selective pressures sometimes leading to rapid adaptations in their morphology. At this rate of adaptations, researchers can examine which traits are undergoing an evolutionary response to new habitats and identify what factors may influence them. Besides studies on Rhinella marina in Australia, the use of invasive species as a model for studying ecological and evolutionary processes remains an emerging field of research. This thesis examines the morphological changes of another invasive amphibian, Xenopus laevis, comparing native (South Africa) and invasive (Chile, France, Italy, and Portugal) populations. Organ size and reproductive investment of X. laevis individuals were compared between countries and sexes. There were significant differences in organ size and reproductive investment between populations. Digestive organs and lungs were observed to be larger in invasive populations compared to those in South Africa, suggesting adaptive or plastic changes since their introduction 30-40 years ago. Country-specific changes were also observed as larger hearts were found in X. laevis from Portugal and smaller livers in those from France. Reproductive organs and fat reserves of female Xenopus laevis also differed in size between countries; however, these results may reflect differences in the date of capture relative to the reproductive cycle. The comparative study of X. laevis morphology between countries presented in this thesis provides a first overview of rapid evolutionary events in an invasive amphibian and suggests that the use of invasive species as models for studying evolution may provide important insights into evolutionary processes. |
