Host shifts Wing morphology 6 cactus 6 fly 6 host plant 6 Alkaloids 4 Cactus 4 Viability 4 adult 4 alkaloid 4 concentration (composition) 4 evolutionary biology 4 fitness 4 herbivore 4 life cycle 4 viability 4 Adaptation, Biological 2 Animals 2 Cactaceae 2 Cactophilic Drosophila 2 Drosophila 2 Drosophila antonietae 2 Drosophila buzzatii 2 Drosophila gouveai 2 Female 2 Genitalia, Male 2 Hybridization, Genetic 2 Hybrids 2 Male 2 Male genitalia 2