Paraphyly in Hawaiian hybrid blowfly populations and the evolutionary history of anthropophilic species.

Abstract

Complementary nuclear (28S rRNA) and mitochondrial (COI + II) gene markers were sequenced from the blowflies, Lucilia cuprina and Lucilia sericata, from Europe, Africa, North America, Australasia and Hawaii. Populations of the two species were phylogenetically distinct at both genes, with one exception. Hawaiian L. cuprina possessed typical L. cuprina-type rRNA, but had L. sericata-type mitochondrial (COI + II) sequences. An explanation for this pattern is that Hawaiian flies are hybrids and comparison of observed levels of sequence divergence to possible introduction events, e.g. Polynesian colonization, suggests that Hawaiian L. cuprina may be evolving rapidly. Moreover, the monophyly of these flies also suggests that the L. sericata mtDNA haplotype was apparently fixed in Hawaiian L. cuprina by lineage sorting, indicating a population bottleneck in the evolutionary history of these island flies.