Genomic insights into gene family evolution and salivary gland gene expression associated with dietary shifts in hemiptera

Hemiptera exhibits repeated and independent transitions among distinct feeding strategies, including phytophagy, carnivory, omnivory and hematophagy, a trait that offers an ideal model system to dissect the genomic basis of dietary adaptation. To comprehensively explore the dynamic genomic changes accompanying dietary adaptation, we performed comparative genomic analyses on 27 hemipteran species, which collectively represent four distinct feeding habits. Our analyses uncovered extensive genomic changes associated with dietary adaptation, including the expansion, contraction, and loss of gene families. We observed functional-level convergence in enriched biological processes across independent lineages undergoing parallel dietary shifts, despite limited overlap at the specific gene family level, as well as recurrent changes in specific gene families during reverse transitions. Moreover, comparative transcriptomic analysis of salivary glands across these species identified numerous species-specific genes and gene families may be associated with feeding biology, generating candidate hypotheses for future functional validation. Together, our results provide insights into the dynamic genomic architecture underlying dietary diversification in hemipterans and highlight candidate genes and pathways for future experimental investigation of dietary adaptation mechanisms.