Temperature stress disrupts reciprocal adaptation in a microbial predator-prey system

Antagonist interactions, such as predator-prey interactions, are widespread in nature and drive both ecological and evolutionary outcomes. Coevolutionary outcomes of antagonistic interactions have been shown to be influenced by environmental conditions, yet the role of abiotic stress in modifying these outcomes remains insufficiently understood. Here we explored how the addition of temperature stress altered evolutionary trajectories of traits of both species in the Pseudomonas fluorescens-Tetrahymena pyriformis (bacteria-ciliate) predator prey system. We found that temperature stress impeded the evolution of traits important for antagonistic interactions in both species. Prey defense levels as well as predators' ability to eat prey were limited under temperature stress. We also found that the addition of temperature stress altered growth rate evolution in evolving populations of both species. Taken together, our results show that temperature stress not only alters the evolutionary trajectories of both predator and prey traits but also hinders their coevolution. These findings suggest that environmental stressors may weaken reciprocal coevolution which could have important consequences for the stability and persistence of ecological communities.