Transcriptome-Based Identification of Highly Similar Odorant-Binding Proteins among Neotropical Stink Bugs and Their Egg Parasitoid

Olfaction plays a fundamental role in insect survival through resource location and intra and interspecific communications. We used RNA-Seq to analyze transcriptomes for odorant-binding proteins (OBPs) from major stink bug pest species in Brazil, Euschistus heros , Chinavia ubica , and Dichelops melacanthus , and from their egg parasitoid, Telenomus podisi . We identified 23 OBPs in E . heros , 25 OBPs in C . ubica , 9 OBPs in D . melacanthus , and 7 OBPs in T . podisi . The deduced amino acid sequences of the full-length OBPs had low intraspecific similarity, but very high similarity between two pairs of OBPs from E . heros and C . ubica (76.4 and 84.0%) and between two pairs of OBPs from the parasitoid and its preferred host E . heros (82.4 and 88.5%), confirmed by a high similarity of their predicted tertiary structures. The similar pairs of OBPs from E . heros and C . ubica may suggest that they have derived from a common ancestor, and retain the same biological function to bind a ligand perceived or produced in both species. The T . podisi OBPs similar to E . heros were not orthologous to any known hymenopteran OBPs, and may have evolved independently and converged to the host OBPs, providing a possible basis for the host location of T . podisi using E . heros semiochemical cues.