Effect of intraspecific variation in fruit traits on animal sensory ecology

Abstract Seed dispersal by animals is critical to both animal and plant ecology. Among species, fruits show a tremendous diversity of traits such as colour, scent, texture and size. Recent studies demonstrated a significant degree of variation in fruit traits within species as well. This often-overlooked variation may play a critical role in animal–plant interactions as they can inform fruit selection and be the basis for the evolution of interspecific variation. Yet data on the role of intraspecific variation on animal behaviour are rare. We combine behavioural and fruit trait data to test whether sensory ecology is driven by: (H1) intraspecific variation in fruit traits; and/or (H2) traits that are correlated with fruit quality. Our overarching hypothesis is that variation within a species will lead to differential deployment of senses across species. We collected sensory behaviour of wild red-bellied lemurs and quantified intraspecific variation in the traits of six consumed fruit species. We found support for both: the use of olfaction was significantly associated with both intraspecific variation in fruit scent and its association with sugar content. This underscores the significance of intraspecific variation in plant traits to animal sensory ecology, as well as their potential implications for fruit trait evolution.