Discussion

The blowfly genus Lucilia is composed largely of saprophages and facultative myasis agents, including the economically important species Lucilia cuprina and Lucilia sericata. Only one species is generally recognised as an obligate agent of myiasis, Lucilia bufonivora Moniez, and this is an obligate parasite of toads. Lucilia silvarum (Meigen), a sister species, behaves mainly as a carrion breeder, however, it has also been reported as a facultative parasite of amphibians. Morphologically, these species are almost identical and historically this has led to misidentification, taxonomic ambiguity and a paucity of studies of L. bufonivora. In this study, dipterous larvae were analysed from toad myiasis cases from the UK, The Netherlands and Switzerland, together with adult specimens of fly species implicated in amphibian parasitism: L. bufonivora, L. silvarum and Lucilia elongata. Partial sequences of two genes, COX1 and EF1α, were amplified. Seven additional blowfly species were analysed as outgroups. Bayesian inference trees of COX1, EF1α and a combined-gene dataset were constructed. All larvae isolated from toads were identified as L. bufonivora and no specimens of L. silvarum were implicated in amphibian myiasis. This study confirms L. silvarum and L. bufonivora as distinct sister species and provides unambiguous molecular identification of L. bufonivora.