Insect olfactory systems have evolved to recognize phytochemicals and respond to olfactory-triggered cues that vary depending on needs. Several Bactrocera species are attracted explicitly to particular phytochemicals, including methyl eugenol (ME) and cue lure/raspberry ketone (CL/RK). The attraction of Bactrocerans to ME/RK is primarily driven by olfaction. Therefore, the divergent behavioral phenotypes are due to the differences in genes expressed in antennae. High quality transcriptomes were generated with mRNA from dissected antennae, to analyze the differences in olfaction-related genes of three ME-responders B. dorsalis, B. papayae and B. correcta and two RK-responders B. cucurbitae and B. tau. Many distinct quantitative and qualitative differences were identified in their respective chemosensory repertoires. Tissue- and sex-specific expression analyses identified antennae-predominant and sex-biased chemosensory genes. Sequence comparison revealed variations among family members of odorant-binding proteins and odorant-receptors between ME-responders and RK-responders. Differences in composition, expression levels, and sequence of proteins encoded by olfactory-related genes were identified between ME-responders and RK-responders. Some of the differences might contribute to the divergence in response to plant-derived odorants. Taken together, our results provide insights into the evolution of an olfactory system at molecular level in Bactrocera ME- and CL/RK-responding species.

昆虫嗅觉系统已经发展为识别植物化学物质，并对嗅觉触发的线索做出反应，这些线索根据需要而变化。几种芽孢杆菌属物种明确吸引了特定的植物化学物质，包括甲基丁子香酚（ME）和提示诱剂/覆盆子酮（CL / RK）。Bactrocerans对ME / RK的吸引力主要是由嗅觉驱动的。因此，不同的行为表型是由于触角表达基因的差异所致。用解剖后触角的mRNA生成高质量的转录组，以分析三个ME应答者背侧双歧杆菌，木瓜双歧杆菌和正确双歧杆菌以及两个RK应答者葫芦形芽孢杆菌和B.头。在它们各自的化学感觉库中鉴定出许多不同的数量和质量上的差异。组织和性别特异性表达分析确定了以触角为主导和性别偏向的化学感觉基因。序列比较揭示了ME响应者和RK响应者之间的气味结合蛋白和气味受体的家族成员之间的差异。在ME应答者和RK应答者之间鉴定了嗅觉相关基因编码的蛋白质的组成，表达水平和序列的差异。某些差异可能会导致对源自植物的增香剂的差异。两者合计，我们的结果提供了洞察到的Bactrocera ME和CL / RK响应物种中的嗅觉系统的分子水平的演变。