Intraspecific geographical variability of Phlebotomus perniciosus assessed by MALDI-TOF MS protein profiling

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) protein profiling has emerged over the last decade as a method of choice for species identification of many medically important arthropods. However, the influence of intraspecific variability on the performance of this popular technique has seldom been tested. This study provides the first standardized comparison of different geographical populations of Phlebotomus perniciosus, a vector of Leishmania infantum and Toscana virus in the western Mediterranean, by MALDI-TOF MS protein profiling.

Phlebotomus perniciosus males were collected in five countries (Portugal, Spain, France, Italy, Croatia) that represent most of its distribution in Europe. All samples were trapped, stored and processed according to a highly standardized protocol to avoid effects other than geographical origin on their protein spectra acquired by MALDI-TOF MS protein profiling. The obtained protein spectra were compared with laboratory-reared specimens of Ph. perniciosus.

Twenty-two analysed specimens from five geographical populations provided protein spectra that were highly similar, species-specific and clustering according to their quality. No grouping according to geographical origin was observed, and the protein spectra of field-collected specimens showed similar composition and complexity to spectra from Ph. perniciosus laboratory colony-reared in captivity for several decades.

Our findings demonstrate that in samples of a same sex, with the same collection method and storage time, MALDI-TOF MS protein profiling does not reflect the geographical origin of analysed specimens, confirming the value of this technique for high-fidelity and reproducible species identification of sand flies regardless of their geographical origin.