Vector-borne pathogens can influence the physiology of their vectors and hosts, enhancing pathogen transmission and affecting their ecology. Porras et al. found that infection with the barley yellow dwarf virus (BYDV) elevated the surface temperature of infected host plants by an average of 2 °C and led to the upregulation of three heat-shock protein genes in the BYDV aphid vector Rhopalosiphum padi, enhancing thermal tolerance by 8 °C. Remarkably, the authors found that this enhancement in thermal tolerance allowed aphids to inhabit higher and warmer regions of infected host plants when they became displaced from cooler regions by Rhopalosiphum maidis, a larger aphid species. These results show that viral infection can have profound effects on thermal biology of hosts and vectors, resulting in drastic changes to the environmental niche of the vector.