Species-specific scents help willows recruit their predators

​In a new study published in Functional Ecology, we investigated how plant volatile signals influence predator attraction in willows. The study tested whether herbivore-specific cues can shape plant defences and alter interactions with natural enemies under field conditions.

We conducted a field experiment with two common willow species, Salix cinerea and Salix fragilis. Branches were treated with mechanical damage or extracts from caterpillars and leaf beetles. We then measured volatile organic compound (VOC) emissions, leaf reflectance, and predation on artificial caterpillars. The two willow species used contrasting defence strategies. In S. fragilis, herbivore treatments triggered strong and specific VOC responses. These signals attracted more invertebrate predators, particularly when caterpillar cues were present. In contrast, S. cinerea showed weaker inducible responses. Here, bird predation correlated more with background chemical and visual traits than with induced signals. These results show that closely related plants can recruit different predator guilds. They also demonstrate that the ecological role of herbivore-induced plant volatiles depends on species-specific defence strategies.

Mezzomo P.,  Leong J. V.,  Vodrážka P., Moos M., Özcan E., Bina D., Ré Jorge L., Volfová T.,  Pokorný V., Volf M., (2026) Species-specific scents, targeted enemies: Volatile cues mediate predator attraction in willows. Functional Ecology, https://doi.org/10.1111/1365-2435.70289