Environmental visual complexity increases the foraging success of mesopredators by promoting explorative behaviours

The visual complexity of a habitat can play a significant role in the outcome of interactions between predators and prey. We currently assume that predators should maximize their foraging success by foraging in habitats where prey are easier to detect and search times are lower. Mesopredators, however, have to detect prey (as a predator) while also avoiding detection by their own predators (as prey). The predicted trade-off between foraging success and perceived predation risk for mesopredators is likely to be affected by the visual complexity of their surroundings, although this remains to be tested. Using two immersive augmented-reality experiments, we tested whether risk aversion and foraging success of a model mesopredator (individual three-spined sticklebacks, Gasterosteus aculeatus ) changed in habitats with differing visual complexity. Despite being motivated to forage, individuals consistently preferred to associate with regions of higher complexity. However, contrary to our predictions, sticklebacks also had higher foraging success in these habitats. This appeared to be driven by increases in exploration and foraging in visually complex habitats, changing their likelihood of encountering prey. Our findings highlight how environmental visual complexity alone can induce a behavioural shift in mesopredators from risk-averse behaviours to those associated with exploration and foraging, ultimately changing where and when predators choose to hunt while mitigating predicted trophic trade-offs. • Mesopredators need to balance detecting prey with evading predators. • Visually complex habitats should be lower risk but also increase detection times. • Sticklebacks prefer visually complex areas where they increase their exploration. • Increased exploration results in greater foraging success in these habitats. • Visual complexity alone can mitigate the predicted trade-offs facing mesopredators