Volatile Predator Cues Drive Non-Consumptive Effects in an Agroecosystem

Sara Hermann and Jennifer Thaler
Department of Entomology, Michigan State University; Department of Entomology, Cornell University

Presented at the All Scientists Meeting (2015-04-15 to 2015-04-16 )

Predators can affect prey in two ways—by reducing their density (consumptive effects) or by changing their behavior, physiology or other phenotypic traits (non-consumptive effects). Understanding the cues and sensory modalities prey use to detect predators is critical for predicting the strength of non-consumptive effects and the outcome of predator–prey encounters. While predator-associated cues have been well studied in aquatic systems, less is known about how terrestrial insect prey detect their predators. We evaluated how Colorado potato beetle, Leptinotarsa decemlineata, perceive predation risk by isolating cues from its stink bug predator, the spined soldier bug, Podisus maculiventris and in field trials where predators where confined on plants. Field experiments showed reduced damage to plants where predators where contained nearby. Volatile odor cues from predators reduced beetle feeding overall, although male predators caused a stronger reduction than females. Headspace volatile collections from the predators allowed us to pinpoint three major chemical players in this interaction. In laboratory assays, beetle larvae avoid these chemicals and eat less in their presence. The augmentative use of these chemicals in the field may lead to reduced damage in potato fields.

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