Abstract : Cognition refers to the mechanisms by which animals acquire, store, process and act on information from the environment and this include perception, learning, memory and decision making. Animals have their own perceptual world and adaptation seems to be crucial in order to survive by developing specialized ability in regard of the relevance of each sensory information. The process of storage is another mechanism important for adaptation because learned information can be retained from one occasion to the next. The underlying mechanisms of behavioral adaptation are based on the learning and phenotypic plasticity. How this plasticity induces the formation of these adaptive specialized modules still remains unsolved. The general aim of this PhD hold on the modularity and plasticity of olfactory learning and memory ability in Drosophila melanogaster. Drosophila is always confronted to complex environments with generally more than one stimulus that need to be associated with positive or negative reinforcements. In laboratory, it is possible to reproduce that kind of behavior in various protocols of associative learning. I tested adaptation processes at different level of information processing. I demonstrate in this manuscript that adaptation occurs at each level: perception of complex stimuli, storage of relevant information and also update of memory trace not relevant anymore. This processes revealed the existence of adaptive modules more or less specialized that allows the animal to adapt to its specific environment. Moreover, artificial selection on specific memory ability demonstrates the implication of evolution in the modularity of animal cognition.