Insect chemosensory systems, such as smell and taste, are mediated by chemosensory receptor and non-receptor protein families. In the last decade, many studies have focused on discovering these families in Tephritidae species of agricultural importance. However, to date, there is no information on the Mexican fruit fly Anastrepha ludens Loew, a priority pest of quarantine importance in Mexico and other countries. This work represents the first effort to identify, classify and characterize the six chemosensory gene families by analyzing two head transcriptomes of sexually immature and mature adults of A. ludens from laboratory-reared and wild populations, respectively. We identified 120 chemosensory genes encoding 31 Odorant-Binding Proteins (OBPs), 5 Chemosensory Proteins (CSPs), 2 Sensory Neuron Membrane Proteins (SNMPs), 42 Odorant Receptors (ORs), 17 Ionotropic Receptors (IRs), and 23 Gustatory Receptors (GRs). The 120 described chemosensory proteins of the Mexican fruit fly significantly contribute to the genetic databases of insects, particularly dipterans. Except for some OBPs, this work reports for the first time the repertoire of olfactory proteins for one species of the genus Anastrepha, which provides a further basis for studying the olfactory system in the family Tephritidae, one of the most important for its economic and social impact worldwide.

The pepper weevil Anthonomus eugenii is one of the most damaging pests to the pepper crop. To offer alternative management strategies to insecticides, several studies have identified the semiochemicals that are involved in the pepper weevil’s aggregation and mating behavior; however, there is no information on its perireceptor molecular mechanism, to date. In this study, bioinformatics tools were used to functionally annotate and characterize the A. eugenii head transcriptome and their probable coding proteins. We identified twenty-two transcripts belonging to families related to chemosensory processes, seventeen corresponding to odorant-binding proteins (OBP), and six to chemosensory proteins (CSP). All results matched with closely related Coleoptera: Curculionidae homologous proteins. Likewise, twelve OBP and three CSP transcripts were experimentally characterized by RT-PCR in different female and male tissues. The results by sex and tissue display the different expression patterns of the AeugOBPs and AeugCSPs; some are present in both sexes and all tissues, while others show expressions with higher specificity, which suggests diverse physiological functions in addition to chemo-detection. This study provides information to support the understanding of odor perception in the pepper weevil.

The Mediterranean fruit fly (Ceratitis capitata Wiedemann, medfly) is a highly invasive agricultural pest with a considerable threat to global fruit production. Its olfactory system, mediated by odorant-binding proteins (OBPs), plays a fundamental role in key behaviors such as host localization, mate recognition, and oviposition site selection. This study presents a comprehensive homologation and systematic reclassification of CcapOBPs through comparative genomic analyses with the model organism Drosophila melanogaster Meigen and 8 Tephritidae species (tribes Dacini, Toxotrypanini, and Trypetini), supported by Bayesian phylogenetic inference. By integrating 2 genome assemblies (Ccap_2.1 and EGII-3.2.1), additional GenBank entries, a de novo head transcriptome from sexually mature wild males, and comparative analyses with D. melanogaster orthologs, we consolidated 156 candidate sequences into a homologized repertoire of 48 CcapOBPs. RT-PCR validation of 21 representative CcapObps confirmed their expression in male heads and highlighted how the de novo transcriptome recovered genes missing from individual genome assemblies, demonstrating consistency across all data sources. Phylogenetic reconstruction of CcapOBP and tephritid species revealed clustering patterns consistent with the established evolutionary relationships within the family, enabling the identification of ortholog genes, lineage-specific diversification events, gene duplications, expansions in C. capitata. However, limitations were identified in datasets for the other fruit fly species, and the need for nomenclature adjustments based on chromosomal localization. This study represents the most comprehensive OBP homologation in medfly to date, providing a robust framework for understanding the molecular evolution of chemosensory systems in Tephritidae and supporting the development of species-specific and environmentally sustainable pest management strategies.