Integrative Profiling of Floral Volatiles and Odorant-Binding Protein Expression Identifies Candidate Olfactory Components Associated with Host Use in the Polyphagous Mirid Apolygus lucorum

Apolygus lucorum is a polyphagous mirid that moves among flowering hosts, but the chemical and olfactory features associated with this flexibility remain poorly understood. We profiled floral volatiles from seven host plants and examined OBP transcription after laboratory exposure to food- and sex-attractant blends and in field-collected adults. GC–MS detected 112 volatiles, 38 of which occurred in at least two hosts, including α-pinene, β-caryophyllene, and myrcene. However, their shared occurrence reflects chemical overlap and does not, by itself, establish behavioral activity or a role in host recognition. Laboratory transcriptional responses varied with odor blend, sex, and exposure duration. Thirteen OBPs were upregulated in at least two of three field collections relative to laboratory-reared controls. Combining these field-associated patterns with food-attractant responses prioritized five OBPs (OBP1, OBP4, OBP10, OBP16, and OBP29) for functional testing. Because each field host was sampled in a different month, the observed expression differences cannot be attributed to host identity alone. Furthermore, the major recurrent floral compounds were not tested in the laboratory odor blends, leaving their interactions with the prioritized OBPs unresolved. These findings provide chemical and molecular candidates for future studies of host-associated olfaction.