Genomic responses to increased temperature and pollinator selection in Brassica rapa L

Rapid environmental change reshapes both abiotic stress and biotic interactions, yet it remains unclear how these combined forces structure plants' genomic adaptation. In particular, the joint influence of temperature and pollinator identity, two ecological axes undergoing simultaneous global shifts, has rarely been quantified at genomic resolution. We resequenced Brassica rapa L. plants after a six-generation evolution experiment, combining two temperature regimes (ambient vs hot) with three pollination treatments (bumblebee, butterfly, and mixed bumblebee-butterfly), and glasshouse control, to assess how these factors shape genomic responses. Using multiple complementary statistics (allele-frequency trajectories, F_ST outliers, Cochran-Mantel-Haenszel tests, and local score analyses), we found that adaptive genomic responses differed sharply among pollinators and temperatures: warming strengthened selection in community-level pollination, yielding the clearest signals in the hot-generalised treatment; bumblebee pollination showed strong but drift-obscured genomic change; and butterfly treatments exhibited minimal genomic response. Our findings demonstrate that pollinator identity and temperature interact nonadditively to produce distinct, highly context-dependent adaptive trajectories. This work highlights the importance of accounting for demographic variation and ecological complexity when predicting evolutionary responses to climate-driven shifts in species interactions.