Non-consumptive effects of odonate predators on pollinators of water lilies

Plant-pollinator interactions are shaped not only by environmental conditions but also by biotic interactions such as predation. Predators influence prey through direct consumption and non-consumptive effects (NCEs) arising from perceived predation risk altering prey traits such as foraging behaviour. Emergent freshwater macrophytes such as the yellow water lily ( Nuphar lutea) create a shared interface where predators and pollinators co-occur. Yet, NCEs of predation risk on pollinators and their consequences for plant-pollinator interactions remain severely understudied, especially at aquatic-terrestrial transition zones. Therefore, we experimentally tested how artificial dragonflies, as standardised visual predation cues, shape the foraging behaviour of pollinators on N. lutea and assessed whether these behaviours were related to natural variation in odonate abundance. We quantified visitation rates and visit durations under artificial dragonfly, neutral object, and control treatments, and related visit duration to natural odonate abundance. Our results showed that artificial dragonfly-like cues reduced visitation rates by up to 50% and visit durations by up to 18 s per visit, across pollinator taxa. Moreover, visit duration showed a negative association with natural odonate abundance. Structural equation models revealed that pollinator behaviour was indirectly associated with environmental conditions (i.e., wind and overcast weather) via their negative effects on odonate abundance. Consequently, our findings demonstrate that predator-mediated NCEs can play a substantial role in shaping pollinator foraging on N. lutea , highlighting that plant-pollinator interactions at freshwater-land ecotones may depend on dynamic predation risks and underlying environmental drivers. These insights are particularly important for understanding macrophyte-insect interactions because communities at aquatic-terrestrial interfaces are especially vulnerable to shifts in environmental conditions on land and water.