The closely related species Lucilia (=Phaenicia) cuprina and L. sericata are widespread, common, and extensively sympatric blow flies. Both may be serious pests of sheep, and both may be collected as evidence during an investigation of human death. A global molecular systematic survey of these flies found a significant lack of concordance between the cladogram based on nuclear 28S rRNA (28S) sequence and that based on mitochondrial cytochrome oxidase (CO) sequence. The 28S tree included lineages corresponding to each of the species as defined by morphological criteria. The CO tree supported a paraphyletic L. cuprina, with specimens from Hawaii as the sister group of L. sericata. Phylogenetic analysis of CO sequences has been proposed as a method for identifying insects collected from a corpse, and these results make it clear that extensive geographic sampling and/or a multi-gene approach should be undertaken before establishing any standards for forensic entomology molecular identification methods.
A possible explanation for this evolutionary pattern is that the Hawaiian L. cuprina are descended from a hybridization event between a female L. sericata and a male L. cuprina with the subsequent loss of L. sericata nuclear alleles. Both flies were probably introduced to Hawaii by human activity, and small initial populations would make the above scenario more likely. However, the observed genetic distances indicate that the L. sericata and Hawaiian L. cuprina CO lineages diverged long before humans first reached the islands. We suggest that islands occupied earlier in the geographic expansion of Polynesian humans be surveyed for the possible origin of the Hawaiian L. cuprina clade.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA