The Adaptive Roles of Active Transposable Elements in Insect Hosts.
Active transposable elements (TEs) are capable of generating new insertions in genomes and have historically been viewed as genomic parasites due to their largely detrimental or neutral effects. However, emerging evidence suggests that these elements also play a crucial role in driving adaptive evolution in insects. This mini-review synthesizes recent findings on how active TEs contribute to insect adaptation through various mechanisms, including regulation of gene expression, structural variation, and epigenetic effects. Notable examples of adaptation driven by active TEs include their roles in insecticide resistance, morphological adaptations, tolerance to harsh climates, and antiviral immune responses. We argue that while host silencing mechanisms, such as the piRNA pathway, tightly regulate TE activity to minimize harmful effects, the context-dependent activation of active TEs can generate beneficial genetic variation that enhances insect adaptations to anthropogenic and climatic pressures. Future research that integrates long-read sequencing, single-cell omics, and gene editing techniques will provide a robust mechanistic foundation for understanding the adaptive significance of active TEs in insects, with important implications for pest management, pollinator protection, and evolutionary biology.