Individual variation in perceived density and its impacts on the realization of ecological niches

Organisms gain information about their local environment using different senses. Variation in both reception and assessment of stimuli leads to differences among individuals in their perception of environments. Here, we highlight the importance of acknowledging and investigating such individual differences by focusing on perceived density, the individual’s assessment of local density. We summarize how individuals sense their environment and identify factors shaping variation in sensory uptake and processing. We argue that differentially perceived environments likely affect relevant processes under selection, which contribute to the realization of individualized ecological niches. Ultimately, we provide practical guidelines for studying perceived density and present potential emergent consequences when considering individual differences, which will advance the in-depth understanding of individual and population-wide behavioural phenomena.