Apis mellifera multi-omics responses to ectoparasitic mites: unveiling biomarkers for Tropilaelaps mercedesae and Varroa destructor in honeybee hemolymph through hemolymph peptide and proteome analysis using MALDI-MS and LC-ESI-MS/MS

Varroa destructor and Tropilaelaps mercedesae are ectoparasites that pose a significant threat to honeybee populations. It is essential to understand their impact to develop effective management strategies. In this study, we examined the relative abundance of proteins and the expression of immune-related genes in A. mellifera parasitized by the two mites using mass spectrometry analysis of hemolymph and transcriptomics of bleeding honeybees. The study revealed the modulation of genes and proteins associated with immune response and stress management. The apidaecin gene was upregulated in Varroa-infested honeybees and downregulated in Tropilaelaps-infested honeybees, a finding that correlated with MALDI-MS data. Furthermore, variations in the abundance of Hexamerin, Odorant Binding Protein 21, Phenoloxidase and Transferrin were observed in Varroa- and Tropilaelaps-infested honeybees. Using proteomics, potential markers associated with immunity, metabolism and stress responses (e.g. high Glx storage protein, alpha-glucosidase, glyoxylate/hydroxypyruvate reductases) were found to be specific to Varroa and Tropilaelaps infestations. Two Deformed Wing Virus (DWV) proteins exhibit higher abundance in the hemolymph of Tropilaelaps-infested honeybees compared to non-infested and Varroa-infested honeybees, suggesting that Tropilaelaps may weaken honeybee immunity, potentially exacerbating viral infections and colony health decline. This indicates that studying host-mite species interactions could lead to a better understanding of honeybee protection.