Experimental hybridization in cactophilic Drosophila and the effects of host plants on morphological divergence

BARBARICH, MARÍA F.; SOTO EDUARDO; PADRO JULIAN; SOTO IGNACIO M.

Cuernavaca

Congreso; conferencias de ?Genómica de Poblaciones de México (MexPopGen); 2023

The ability to utilize decaying cactus tissues as breeding andfeeding sites is a key aspect that allowed the successful diversification of theDrosophila repleta group in American deserts and arid lands. Within thisgroup, the Drosophila buzzatii cluster is a South American clade of sevenclosely related species in different stages of divergence, a valuable modelsystem for evolutionary research. Here we studied the genetic basis ofhost-associated morphological differences of D. koepferae and D. antonietae,the last pair of species to diverge in this group. We measured wing andgenital morphology in males of D. koepferae and D. antonietae, hybrids andbackcrosses reciprocally raised in each of their host plants. This approachprovided a source of genetic diversity, allowing the dissection ofenvironmental and genetic effects in organs predicted to be involved insexual selection and dispersal ability. We observed non additive inheritanceand a genotype-host interaction in both wing and genitalic shape, while forwing size the only factor affecting the trait was the rearing host. Geneticdisturbances elicited by the hybridization were largely dependent on the hostplant. Our results support an ecological model of speciation for cactophilicDrosophila with cacti diversity as the major driver of phenotypic and geneticdivergence among these species