Patterns of Allozyme Relationships Compared With Morphology, Hybridization, and Geologic History in Allopatric Island-Dwelling Mosquitoes

Abstract

Allozyme relationships were compared with morphology, interspecific hybridization, and geologic history in 14 closely-related species in the Aedes (Stegomyia) scutellaris subgroup. The phylogeny generated by the electrophoretic data was generally in agreement with morphological classifications except that one morphologically distinct species pair (A. alcasidi and A. malayensis) showed only populational differentiation and several nearly identical morphological pairs in Polynesia (e.g., A. pseudoscutellaris and A. polynesiensis) were very distant genetically. A molecular clock, based on the ratio between genetic distance and divergence time (one unit of Nei's distance = 11 million years) inferred from a dated geologic event, was used to compare zoogeography, morphology, and biochemical relationships. Genetic distances between species from the Solomon Islands and the Vanuatu-Polynesia area correspond to an early Pliocene separation of these areas. An invasion of Micronesia occurred approximately 5 million years ago. Most remaining speciation occurred during the mid-Pliocene as islands moved into their present-day positions. The close relationship between southeast Asian and Philippine species could have resulted from the recent onset of isolation in the Pleistocene. Interspecific hybridization potential was not significantly correlated with Nei's genetic distance. Many quite distantly related species readily hybridize, while some closely related pairs show only unidirectional compatibility. Slight interspecific morphological divergence and the independence of hybridization capabilities from phylogeny are not unexpected in a group in which species are allopatric and occupy similar habitats.

Genetic divergence in the Chorthippus parallelus species group (Orthoptera: Acrididae)

“…A discrepancy of this type between apparent rates of electrophoretic and morphological evolution has been observed previously in several groups (e.g. snails, Clarke, Murray &Johnson, in press; mosquitoes, Pashley, Rai & Pashley 1985;Hawaiian Drosophila, Sene & Carson, 1977;and see Lambert & Paterson, 1982) and should not be unexpected since different characters are bound to be subjected to different selective regimes. In general, genetic distances based on electrophoretic data evolve in a more uniform way than morphological distances and, as a result, provide a better guide to relationships between taxa (Thorpe, 1982).…”

Biochemical Taxonomy and Enzyme Electrophoretic Profiles During Development, for Three Morphologically SimilarAedesSpecies (Diptera: Culicidae) of the SubgenusStegomyia

“…Heterozygosity in the laboratory strains were generally lower (2Ð18%) than those observed in Þeld samples of several species of the A. scutellaris species group (Pashley et al 1985)Ñthe group within the subgenus Stegomyia in which A. albopictus and A. flavopictus are included. In contrast, the percentage of polymorphic loci was similar to Þeld populations of A. albopictus (Pashley et al 1985, Urbanelli et al 2000 as was the number of alleles per locus (Kambhampati andRai 1991, Urbanelli et al 2000). Therefore, although the overall variability was decreased, an expected level of variant classes was represented.…”

Satyrization and satyrization‐resistance in competitive displacements of invasive mosquito species

“…albopictus is the only member broadly distributed throughout Southeast Asia (Huang, ). Many of the restricted range members of the Scutellaris subgroup are found only on islands, where allopatry has contributed to their ethological and genetic isolation (McClain et al ., ; Pashley et al ., ). Pashley et al .…”

“…() proposed a late Miocene ancestor of this group invading the South Pacific, at a time when dispersal along the Outer Melanesian Arc might have contributed to gene flow. Subsequent geographical isolations drove speciation in the Scutellaris subgroup in the Pliocene and early Pleistocene (Pashley et al ., ). We propose that the unique capacity of Ae.…”