Sensing volatiles throughout the body: geographic‐ and tissue‐specific olfactory receptor expression in the fig wasp.

An essential adaptive strategy in insects is the evolution of olfactory receptors (ORs) to recognize important volatile environmental chemical cues. Our model species, <italic>Ceratosolen fusciceps</italic>, a specialist wasp pollinator of <italic>Ficus racemosa</italic>, 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 <italic>ORs</italic> in the species and reconstructed the phylogeny of <italic>Ceratosolen</italic> ORs in conjunction with other hymenopteran species. Expression analysis showed that though <italic>ORs</italic> were mainly expressed in the female antennae, 20% were also expressed in nonantennal tissues such as the head, thorax, abdomen, legs, wings, and ovipositor. Specific upregulated expression was observed in <italic>OR30C</italic> in the head and <italic>OR60C</italic> in the wings. We identified <italic>OR</italic> expression from all major body parts of female <italic>C. fusciceps</italic>, suggesting novel roles of <italic>ORs</italic> throughout the body. Further examination of the <italic>OR</italic> expression of <italic>C. fusciceps</italic> in widely separated geographical locations, that is, South (urban) and Northeast (rural) India, revealed distinct <italic>OR</italic> 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 <italic>ORs</italic> and their expression across geographical locations and tissues. [ABSTRACT FROM AUTHOR]