Abstract
Background.
MALDI-TOF MS is an innovative tool for identifying both hematophagous and non-hematophagous arthropods at various life stages. However, identification by MALDI-TOF MS requires currently, euthanizing of the specimen, hindering further phenotypic tests. All arthropods have a common factor which is the molting of their exoskeletons, called exuviae. This phenomenon is indispensable for their growth and metamorphosis, and can evidence past arthropod presence.
Objective.
This study assessed the performance of MALDI-TOF MS biotyping for arthropod identification using exuviae from nine distinct laboratory-reared species (Aedes aegypti, Anopheles coluzzii, Cimex lectularius, C. hemipterus, Pediculus humanus corporis, Triatoma infestans, Rhodnius prolixus, Supella longipalpa and Blatta germanica) and compared it efficiency with molecular biology approach.
Results.
Molecular analysis showed low DNA quantity in exuviae (n = 108) across species, resulting low success of COI, 16s, and 18s amplification (50.0%), depending on the species and sequencing (10.2%). The establishment of exuviae protocol for MS submission, yielded MS spectra of high reproducibility and specificity per species. After upgrading home made reference MS database with exuviae spectra, query with remaining spectra revealed that 100% of samples were correctly identified, with 85.8% (278/324) exceeding the threshold score value for reliable identification.
Conclusion.
MALDI-TOF MS shown it high efficiency to identify various arthropod species based on their exuviae. This approach is a groundbreaking development in the field of entomology underlining that MALDI-TOF outperformed traditional methods of exuviae identification, including morphological and molecular tools. It allows also to prevent specimen sacrifice which could be used for complementary analyses.