Host-dependent phenotypic plasticity of male genital morphology in cactophilic sibling Drosophila of the repleta group (Diptera, Drosophilidae)

SOTO IM; MANFRIN, MH; HASSON, E

JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH

Blackwell Publishing Group

Año: 2008

0947-5745

Fast evolution of male genital morphology is a characteristic feature in several animal groups. Such rapid divergence makes this trait a useful key for species identification. The aedeagus, the intromittent organ of male genitalia, is considered the main diagnostic trait for species recognition in the Drosophila repleta group. In this work we analyzed phenotypic plasticity and genetic variation associated to aedeagus size and shape in the cactophilic sibling species Drosophila gouveai Tidon-Sklorz and Sene and D. antonietae Tidon-Sklorz and Sene. Phenotypic plasticity in genital morphology was evaluated in terms of the response to rearing media prepared with each species’ natural host plant, Pilosocereus machrisis Dawson and Cereus hildmannianus Schum. Our results showed that genitalic shape differed significantly between species. and that both shape and size presented host-related phenotypic plasticity in both species. Flies reared in P. machrisis had, on average, larger aedeagi than those grown in C. hildmaniannus. Aedeagus general shape also differed significantly between flies emerged in different cactus hosts. Patterns of variation in genital morphology are discussed in the light of the current knowledge of evolutionary relationships and host plant use, in the D. buzzatii cluster, a group of species in active cladogenesis.