Adaptación a las defensas químicas del hospedador como promotor de la evolución morfológica del ala y la inestabilidad del desarrollo en drosófilas cactófilas

Host plants exert strong selective pressures on phytophagous insects, and shifts in host use or specialisation can influence various phenotypic traits, including morphology. In this study, we examined the effects of adaptation to host secondary metabolites and potential host shifts on wing morphology and developmental instability in two sibling species of cactophilic Drosophila, D. buzzatii and D. koepferae.Using different strains of each species obtained through an artificial selection experiment and host shift simulations, we applied geometric morphometrics to analyse how experimental evolution and novel host exploitation impact wing morphology and developmental instability.Our results showed that adaptation to high concentrations of host secondary metabolites led to a reduction in wing size in D. buzzatii, whereas no such cost was detected in D. koepferae. Additionally, evolutionary changes in wing shape were observed.Host shift simulations resulted in reduced wing size, increased developmental instability and alterations in wing shape in both Drosophila species.In D. koepferae, developmental instability was negatively correlated with wing size, supporting the hypothesis that fluctuating asymmetry serves as a fitness proxy.Our findings highlight the role of correlated evolution following ecological specialisation to host plant chemicals as a key driver of morphological evolution in phytophagous insects.