Evolution of overwintering strategies in Eurasian species of the Drosophila obscura species group

Abstract

The phylogenetic relationship of Eurasian species of the Drosophila obscura species group remains ambiguous in spite of intensive analyses based on morphology, allozymes and DNA sequences. The present analysis based on sequence data for cytochrome oxidase subunit I (COI) and a-glycerophosphate dehydrogenase (Gpdh) suggests that the phylogenetic position of D. alpina is also ambiguous. These ambiguities have been considered to be attributable to rapid phyletic radiation in this group at an early stage of its evolution. Overwintering strategies are diversified among these species: D. alpina and D. subsilvestris pass the winter in pupal diapause, D. bfisciata and D. obscura in reproductive diapause, and D. subobscura and D. guanche without entering diapause. This diversity may also suggest rapid radiation at an early phase of adaptations to temperate climates. O n the other hand, adult tolerance of cold was closely related to overwintering strategy and distribution: D. obscura and D. bfmciata with reproductive diapause were very tolerant; D. alpina and D. subsilvestris which pass the winter in pupal diapause were less tolerant; D. subobscura having no diapause was moderately tolerant and D. guanche occurring in the Canary Islands was rather susceptible. Tolerance of high temperature at the preimaginal stages seemed to be also associated with overwintering strategy; i.e. lower in the species with pupal diapause than in those with reproductive diapause or without diapause mechanism. 0 1999 The Linnean Society of London ADDITIONAL KEY WORDS:-diapausemolecular phylogeny ~ temperature tolerance.

Phylogenetic Utility of Mitochondrial COI and Nuclear Gpdh Genes in Drosophila

“…These genes have been extensively used for phylogenetic analysis in Drosophila (Barrio and Ayala, 1997;Gleason et al, 1997;Kwiatowski et al, 1997;Goto et al, 1999Goto et al, , 2000.…”

“…The primers used to amplify COI were F-and R-COI (Gleason et al, 1997;Goto et al, 1999Goto et al, , 2000 Table 2). PCR components were the same as those used for the amplification of Gpdh except the primers.…”

“…Cycle sequencing was performed using five oligonucleotides (GNL-mel, L4BN, R4M, Gpdh-F, and Gpdh-R; Barrio and Ayala, 1997;Goto et al, 1999Goto et al, , 2000 and two oligonucleotides (F-COI and R-COI) for Gpdh and COI fragments, respectively (Table 2). In the sequenc- Goto et al (2000).…”

Phylogenetic Relationships and Climatic Adaptations in the Drosophila takahashii and montium Species Subgroups

“…The primers used to amplify the COI fragment were F-and R-COI (Gleason et al, 1997;Goto et al, 1999) (Table 3). PCR used 100 ng of DNA, 1 U of AmpliTaq Gleason et al (1997).…”

“…Therefore, there is a possibility that tropical or subtropical lowland species had first adapted to subtropical highlands and then colonized temperate regions. To examine this possibility, we analyzed the phylogenetic relationships among temperate, subtropical highland, and subtropical lowland species belonging to these subgroups, based on sequence data of mitochondrial cytochrome oxidase subunit I (COI) and nuclear glycerol-3-phosphate dehydrogenase (Gpdh) genes, which have been extensively used for phylogenetic analysis in Drosophila (Barrio and Ayala, 1997;Gleason et al, 1997;Kwiatowski et al, 1997;Goto et al, 1999). Phylogenetic relationships in these subgroups have been studied by a number of workers (Watanabe et al, 1982;Ohnishi et al, 1983;Ohnishi and Watanabe, 1984;Kim et al, 1989Kim et al, , 1993Shyamala and Ranganath, 1990;Inaba et al, 1993;Parkash et al, 1994), but information on the subtropical highland species is limited.…”