Joint effects of climate warming and other stressors are potentially complex and difficult to predict. In stream ecosystems, exotic riparian species have the potential to alter leaf-shredding detritivorous invertebrate assemblages and leaf litter breakdown due to differences in the quality of litter inputs. This is the case for Eucalyptus plantations, which are widespread, occurring along riparian corridors of streams around the world. Two detritivore species from two locations were studied: the stonefly Diamphipnosis samali in Chile and the caddisfly Calamoceras marsupus in Spain. Eucalyptus leaves affected detritivore growth mainly by direct consumption, while the presence of both Eucalyptus leaves and leachates inhibited the breakdown of native litter. When both litter types were available, breakdown of Eucalyptus leaves was enhanced, possibly as a means of compensatory feeding. Increased temperature exacerbated the negative effect of Eucalyptus on native litter breakdown, possibly because it reduced detritivore survival. These results add to the mounting evidence that joint effects of multiple stressors can be non-additive, and suggest that the sole presence of Eucalyptus leaves and leachates in the water may impact stream communities and ecosystem functions even if native litter is available, with further negative effects to be expected under a warmer climate. informacion[at]ebd.csic.es: Correa-Araneda et al (2015) Joint effects of climate warming and exotic litter (Eucalyptus globulus Labill.) on stream detritivore fitness and litter breakdown. Aquat Sci DOI: 10.1007/s00027-014-0379-y