Host-related life history traits in interspecific hybrids of cactophilic Drosophila

SOTO, EM; SOTO, IM; CARREIRA, VP; FANARA, JJ; HASSON, E

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA

Blackwell Publishing Group

Año: 2008 p. 18 - 27

0013-8703

In the genus Drosophila (Drosophilidae), interspecific hybridization is a rare phenomenon. However, recent evidence suggests a certain degree of introgression between the cactophilic siblings Drosophila buzzatii Patterson & Wheeler and Drosophila koepferae Fontdevila & Wasserman. In this paper we analyze larval viability and developmental time of hybrids between males of Drosophila buzzatii Patterson & Wheeler and females of Drosophila koepferae Fontdevila & Wasserman, raised in media prepared with two natural host plants. In all the cases, developmental time and larval viability in hybrids was not significantly different from parental lines and depending on the cross hybrids developed faster than both species or than the slowest parental species. When data of wing length was included in a discriminate function analysis we observed that both species are clearly differentiated, while hybrids fell in two categories, one intermediate between parental species and the other extreme phenotypes. Extreme phenotypes were fast developing individuals, more viable and had shorter wings in Opuntia sulphurea Gillies ex Salm-Dyck, while they developed more slowly, were more viable and had shorter wings in Trichocereus terschekii Britton & Rose. Thus, our results point out that fitness, as measured by developmental time and viability, of hybrids between Drosophila buzzatii Patterson & Wheeler and Drosophila koepferae Fontdevila & Wasserman is not lower than in parental species.