Comparison of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and Molecular Biology Techniques for Identification of Culicoides (Diptera: Ceratopogonidae) Biting Midges in Senegal

Abstract

Biting midges of the genusCulicoidesare implicated as vectors for a wide variety of pathogens. The morphological identification of these arthropods may be difficult because of a lack of detailed investigation of taxonomy for this species in Africa. However, matrix-assisted laser desorption ionization−time of flight mass spectrometry (MALDI-TOF MS) profiling is efficient for arthropod identification at the species level. This study established a spectrum database ofCulicoidesspp. from Senegal using MALDI-TOF. Identification ofCulicoidesinsects to the species level before mass spectrometry was performed on the basis of morphological characters. MALDI-TOF MS reference spectra were determined for 437 field-caughtCulicoidesof 10 species. The protein profiles of all testedCulicoidesrevealed several peaks with mass ranges of 2 to 20 kDa. In a validation study, 72Culicoidesspecimens in the target species were correctly identified at the species level with a similarity of 95 to 99.9%. FourCulicoidesprotein profiles were misidentified. Nevertheless, six SuperSpectra (C. imicola,C. enderleini,C. oxystoma,C. kingi,C. magnus, andC. fulvithorax) were created. Abdomens of midges were used to amplify and sequence a portion of the mitochondrial cytochrome oxidase I gene (COI). The results obtained using the MALDI-TOF MS method were consistent with the morphological identification and similar to the genetic identification. Protein profiling using MALDI-TOF is an efficient approach for the identification ofCulicoidesspp., and it is economically advantageous for approaches that require detailed and quantitative information of vector species that are collected in field. The database of AfricanCulicoidesMS spectra created is the first database in Africa. The COI sequences of fiveCulicoidesspecies that were previously noncharacterized using molecular methods were deposited in GenBank.