Host plant Adaptation in cactophilic species of the Drosophila buzzatii cluster: fitness and transcriptomics

HASSON, E

Irapuato

Simposio; Simposio Evolution and Ecology: The Droosphila-Cactus model system; 2018

LANGEBIO-University of California San Diego

Host plant shifts in herbivorous insects often involvefacing new environments thatmay speed up the evolution of oviposition behavior, performance related traits,morphology and, incidentally, reproductive isolation. In the genus Drosophila,cactophilic species of the repletagroup include emblematic species in the study of the evolution of host plantutilization. The South American D. buzzatii and its sibling D.koepferae are a model system for the study of differential host plant use.Though these species exhibit a certain degree of niche overlap, the formerbreeds primarily on decaying cladodes of Opuntiacacti while the D. koepferae mainhosts are columnar cacti of the genus Trichocereus. O. sulphureaand T. terscheckii are the among themain hosts in nature. These cacti differ in ecological (spatial andtemporal predictability) and chemical characteristics. Particularly relevant isthe presence of toxic alkaloids in T.terscheckii. Studiesof the effects ofthese cacti and alkaloids revealed theremarkable impact on oviposition behavior, viability, developmental time, wingmorphology, mating success and developmental stability in both species. Recent whole-genomeexpression studies showed that expression profiles are massively affected bythe rearing cactus, and that the presence of alkaloids is the main factormodulating gene expression in D. buzzatii.Functional enrichment analysis indicated that differentially expressed genesare related to detoxification processes and stress response; though genesinvolved in development are an important part the transcriptomic response. Theimplications of our studies in the evolution of host plant use in the repleta group are discussed.