Warming effects on floral volatile organic compounds and plant-pollinator interactions in tropical ecosystems

Climate warming increasingly disrupts plant-pollinator interactions through changes in floral chemical cues, particularly volatile organic compounds (VOCs). Current understanding of temperature effects on plant VOCs is largely derived from studies of foliar emissions in temperate environments and from a limited number of tropical sites, with comparatively little focus on floral VOCs that directly mediate pollination. Floral VOC emissions depend on specialized metabolic pathways derived from primary metabolism and on regulated transport across cellular barriers and the cuticle, processes that are highly sensitive to temperature. Because both biosynthesis and diffusion determine which compounds are released into the atmosphere, warming can alter floral VOC production, blend composition and the timing of emission, potentially reducing floral detectability and impairing pollinator discrimination. In tropical ecosystems, where many plants produce short-lived flowers and rely on specialized pollinators, such changes might rapidly constrain reproduction. In this review, we describe advances in understanding of the temporal dynamics and functional roles of floral VOCs in tropical plants, examine evolutionary and metabolic constraints on floral VOC diversification, and evaluate how warming might influence plant-pollinator interactions by affecting both floral signalling and pollinator physiology and olfactory performance. We show that warming produces compound- and species-specific changes in floral VOC emissions, affecting both the composition and emission rates of compounds that might influence pollinator attraction. We also identify key knowledge gaps and research priorities, including the need to integrate floral chemistry, plant flowering phenology and pollinator sensory ecology to gain a better understanding of the stability of plant-pollinator interactions under climate warming in the tropics.