Evolution of male genitalia: patterns of morphological variation in siblings Drosophila species and their hybrids.

SOTO, IM, V CARREIRA, JJ FANARA AND E. HASSON

BMC EVOLUTIONARY BIOLOGY

BioMEd Central

Lugar: Londres; Año: 2007 vol. 7 p. 1 - 11

1471-2148

Background: The rapid evolution of genital morphology is a fascinating feature that accompaniesmany speciation events. However, the underlying patterns and explanatory processes remain to be settled. In this work we investigate the patterns of intraspecific variation and interspecificdivergence in male genitalic morphology (size and shape) in the cactophilic sibling species Drosophila buzzatii and D. koepferae. Genital morphology in interspecific hybrids was examined and compared to the corresponding parental lines. Results: Despite of being siblings, D. buzzatii and D. koepferae showed contrasting patterns ofgenital morphological variation. Though genitalic size and shape variation have a significant geneticcomponent in both species, shape varied across host cacti only in D. buzzatii. Such plasticexpression of genital shape is the first evidence of the effect of rearing substrate on genitalicmorphology in Drosophila. Hybrid genital morphology was not intermediate between parentalspecies and the morphological resemblance to parental strains was cross-dependent.Conclusion: Our results suggest the evolution of different developmental networks afterinterspecific divergence and the existence of a complex genetic architecture, involving geneticfactors with major effects affecting genital morphology.