Sensing volatiles throughout the body: Geographic and tissue-specific olfactory receptor expression in the fig waspCeratosolen fusciceps

Abstract

AbstractAn essential adaptive strategy in insects is the evolution of olfactory receptors (ORs) to recognize important volatile environmental chemical cues. Our model species,Ceratosolen fusciceps,a specialist wasp pollinator ofFicus racemosa, likely possesses an OR repertoire that allows it to distinguish fig-specific volatiles in highly variable environments. Using a newly assembled genome-guided transcriptome, we annotated 63 ORs in the species and reconstructed the phylogeny ofCeratosolenORs in conjunction with other hymenopteran species. Expression analysis showed that though ORs were mainly expressed in the antennae, 20 percent were also expressed in non-antennal tissues such as the head, thorax, abdomen, legs, wings, and ovipositor. Specific upregulated expression was observed in OR30C in the head and OR60C in the wings. We identified OR expression from all major body parts ofC. fusciceps, suggesting novel roles of ORs throughout the body. Further examination of OR expression ofC. fuscicepsin widely separated geographical locations, i.e., south (urban) and northeast (rural) India, revealed distinct OR expression levels in different locations. This discrepancy likely parallels the observed variation in fig volatiles between these regions and provides new insights into the evolution of insect ORs and their expression across geographical locations and tissues.