A predator pheromone increases potato yield through multiple mechanisms involving plant and prey responses.

Abstract

Predators and their cues can change prey traits, including prey feeding behavior and abundance, even without direct predation. While these nonconsumptive effects are common in agricultural systems, their impact on crop yield is less understood. We investigated the impact of a synthetic predator pheromone on potato tuber yield and its underlying mechanisms within a Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), and predatory stink bug, Podisus maculiventris Say (Hemiptera: Pentatomidae), system. Previous studies demonstrated that releasing the predator pheromone reduces beetle abundance and herbivore damage, and we tested whether this translated into increases in yield. We then tested the mechanisms through which the predator pheromone could increase yield. In addition to the prey responding to predator cues, we tested 2 additional hypotheses: that the pheromone influences predator abundance and plant responses, both potentially contributing to beetle suppression and yield improvement. Over 2 field seasons, pheromone-treated plots showed a 13% increase in tuber yield and fewer Colorado potato beetle larvae, suggesting yield improvement is correlated to reduced beetle abundance. Field observations indicated that stink bug predator densities were too low to significantly impact beetle populations. Instead, in lab experiments, we found that plants exposed to the pheromone flowered earlier and exhibited induced resistance, reducing larval feeding. These findings demonstrate that predator cues can enhance crop yields by influencing both plant and prey responses, highlighting their potential use in integrated pest management.