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

MARTINA S. PERNIGOTTI; SOTO, E.M.; PADRÓ, JULIÁN; SOTO IM,

Cuernavaca

Congreso; Mexico Population Genomics Meeting (MexPopGen); 2023

Universidad Nacional Autónoma de México

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