Ecological and Evolutionary Patterns in Chemoreceptor Expression of LongHorned Beetles (Coleoptera: Cerambycidae)

Abstract

Chemoreceptors are crucial for behaviors such as mate location and host selection in longhorned beetles (Coleoptera: Cerambycidae), yet their evolution and function remain underexplored. To address this, I have annotated chemoreceptors from antennal transcriptomes from nine species of longhorned beetles representing four subfamilies with different larval host preferences (live and dead). My analysis reveals a wide repertoire of gustatory, olfactory, and ionotropic receptors, with several lineages shared across all species, suggesting fundamental roles in cerambycid ecology. Expression patterns vary by species and sex, with differentially expressed genes likely linked to reproductive behaviors. I identified highly expressed candidate pheromone receptors in males of species where females produce sex pheromones, such as Prionus californicus. I also found a significant association between CO₂ receptor expression and host state preference, suggesting a role in host detection. Finally, I observed a high rate of sex-biased expression in odorant receptors in species from the subfamily Lepturinae, suggesting a particularly strong partitioning of chemical ecology between sexes within this subfamily.