Drosophila antonietae 8 Drosophila repleta 8 fly 8 repleta group 8 Cactaceae 6 Diptera 6 Drosophila buzzatii 6 Drosophila gouveai 6 Drosophilidae 6 hybridization 6 Cactus 4 Drosophila koepferae 4 cactus 4 divergence 4 fitness 4 host plant 4 host specificity 4 host use 4 Adaptation 2 Aedeagus 2 Animalia 2 Cereus hildmannianus 2 Clock genes 2 D. buzzatii cluster 2 Drosophila borborema 2 Drosophila repleta group 2 Drosophila serido 2 Drosophila seriema 2 Ecological specialization 2 Experimental design 2