1st Place: Predators under spotlights! Behavioral responses of Orius insidiosus to artifical light spectra and intensities combinations

Supplemental lighting (SL) an efficient tool to disrupt pest activity, including in greenhouses. Despite its current use in controlled environments to promote crops growth, SL potential to favor biocontrol agents have been overlooked, especially regarding predators. Our approach consists of using Light Emitting Diodes (LEDs) to evaluate predation capacity towards spectra × intensity × exposition duration combinations, ultimately selecting them to design optimized lighting conditions both sustaining biocontrol and crops in a commercial context. The predatory bug Orius insidiosus (Say) is an efficient generalist biocontrol agent, widely use against major pests like thrips. However, its photobiology remains mostly unknown and diapause issues are frequent under greenhouse conditions, disrupting biocontrol.

The current experiment corresponds to the first step towards investigation of predators’ responses to light environment at various spatiotemporal scales and focus on O. insidiosus predation capacity at small scale against thrips Frankliniella occidentalis (Pergande). Light spectrum and intensity conditions were finely controlled in independent opaque enclosures. Both prey and predator were exposed to mono and polychromatic spectrum treatments under a range of light intensities, based on previous works with other bug species and wavelengths used to promote crop productivity. Predation performances (attack and capture probabilities, attack numbers, time before first contact, etc.) were analyzed from video tracking data.

To our knowledge, those observations are the first concerning O. insidiosus behavior under SL at small scale, as well as being the initial act towards optimizing SL conditions for this widespread biocontrol agent.