Sensing danger: Energetic and hydric costs of chemoreception in a lizard

Abstract Understanding the benefits and costs of chemoreception and predator avoidance is crucial for unravelling the ecological adaptations of potential prey organisms. In squamate reptiles, tongue flicking is a specialized behaviour used to collect chemical cues from the environment for foraging and predator detection. We hypothesized that the behavioural response to predator scents, and notably chemosensory investigation, incurs both energetic and hydric costs. We conducted two complementary experiments in a small, ground‐active lizard ( Zootoca vivipara ) to assess the energetic and water‐based constraints associated with predator detection and response. First, under controlled exposure to predator scents in a flow‐through system, lizards increased tongue‐flicking rates and thereby metabolic rate and total evaporative water loss. Second, in a laboratory manipulation, chronically dehydrated lizards showed reduced tongue‐flick rates and impaired predator scent discrimination. These findings highlight a trade‐off between water balance regulation and chemoreception, with potential implications for prey–predator interactions in terrestrial ecosystems under drought risk. Thus, energy and water constraints may mediate indirect effects of climate change on species interactions and population dynamics through alterations in sensory capacities. Read the free Plain Language Summary for this article on the Journal blog.