Assessment of MALDI-TOF MS for the identification of cultural heritage insect pests

Abstract

When heritage properties and contents are threatened by various harmful insects, especially coleopterans, rapid and reliable pest identification is required for effective management. While traditional methods have limitations, MALDI-TOF MS has recently emerged as a groundbreaking identification tool. In this study, our aim was to assess the effectiveness of MALDI-TOF MS in identifying cultural heritage insect pests belonging to the Coleoptera order. To do so, adult, larva, and exuviae from eight species of Coleoptera (Lasioderma serricorne (n = 92), Attagenus smirnovi (n = 87), Trogoderma versicolor (n = 97), Reesa vespulae (n = 74), Anthrenus verbasci (n = 68), Anthrenus pimpinellae (n = 34), Anthrenus flavipes (n = 30), and Thylodrias contractus (n = 19), were subjected to MALDI-TOF MS after optimisation of the sample preparation parameters. This optimisation was based on three key parameters influencing spectrum quality: the choice of body part, the buffer volume for protein extraction, and the method and duration of sample homogenisation. Reproducible intra-species MS spectra for each developmental stage were obtained. The species specificity of MS spectra for each developmental stage supported the use of MALDI- TOF MS for specimen classification. Spectra from 68 samples, including four specimens per species and stage, were added to our homemade reference arthropod MS database (DB). Among spectra classified as being consistent, 97.10% (335/345) of the samples were correctly classified with a relevant identification score. The morphological identification of all adult specimens in the reference MS spectra DB was confirmed by molecular biology, and the sequences were deposited in GenBank. This study is the first demonstration of the effective application of MALDI-TOF MS as a reliable tool for identifying various developmental stages of Coleoptera pests which pose a threat to the cultural heritage of France.