Comparative genomic analysis reveals the genetic basis of the environmental adaptability of Propylea japonica

Propylea japonica is a widely distributed natural enemy insect that preys on aphids, whiteflies, and other pests. Owing to its exceptional environmental adaptability, this species serves as an effective biological control agent. However, the molecular mechanisms underlying its environmental adaptation remain poorly understood. Phylogenetic analysis revealed that Coccinellidae diverged from other Coleoptera approximately 194.88 million years ago, and P. japonica and Harmonia axyridis diverged approximately 91.94 million years ago. Collinearity analysis revealed significant fission and fusion events during the chromosomal evolution of P. japonica. Notably, comparative genomic analysis revealed the following five potential key mechanisms underlying the environmental adaptability of P. japonica: (1) sensory specialization: odorant-binding proteins and water sensation genes may enhance prey and water detection; (2) genome stability: histone-mediated chromatin resilience may maintain genome integrity and developmental plasticity under stress; (3) energy trade-offs: prioritizing detoxification or immunity under toxin exposure may reduce the amount of resources allocated to growth or reproduction, enhancing niche adaptation; (4) developmental robustness: juvenile hormone signaling and embryonic development pathways potentially ensure developmental stability; (5) dispersal adaptation: enhanced development of wings and flight muscles and chitinase activity may facilitate colonization to escape extreme climates or resource scarcity. Through comparative genomic analysis, this study provides insights into the divergence history of Coleoptera and reveals a dynamic pattern of chromosomal evolution in P. japonica, clarifying the genetic basis of its environmental adaptation. Future studies should prioritize the functional validation of candidate genes linked to these five key mechanisms to better elucidate their specific contributions to environmental adaptation. This work advances the molecular understanding of ecological adaptation in predatory insects, providing actionable perspectives for optimizing biocontrol strategies.