Identification by MALDI-TOF MS of Coleopteran insect pests collected in the field

BACKGROUND: In the context of museum and cultural heritage protection, rapid and accurate identification of Coleopteran pests is crucial for museum and cultural heritage protection. This study evaluated the effectiveness of MALDI-TOF MS in identifying Coleopteran species collected in the field. MATERIALS AND METHODS: Seven species of Coleoptera collected between 2014 and 2023 from 17 French cultural sites. MALDI-TOF MS spectra were compared against two reference databases: one composed of laboratory-reared specimens and a second expanded with spectra from field-collected specimens. In parallel, three specimens per species and storing mode were submitted to molecular identification using COI and 16S markers. RESULTS: A total of 273 specimens (205 field-collected and 68 laboratory-reared) were analysed. Correct identification at the species were obtained for MS spectra query against DB1 for species which possess homolog in the database. However, the spectra reaching threshold for relevant identification were coming from essentially laboratory-reared Coleoptera. An upgrading of the reference MS database (i.e., BD2), improved identification performance for field specimens, although limitations remained for species with MS spectra of low peak diversity like Pentarthrum huttoni. Molecular identification of field-collected specimens showed a sequencing success rate below 10%. CONCLUSION: MALDI-TOF MS is a promising tool for the identification of Coleopteran pests in cultural heritage contexts, especially when reference spectra matched both species and preservation mode.