Artificial lighting affects the predation performance of the Insidiosus flower bug (Hemiptera: Anthocoridae) against the Western flower thrips (Thysanoptera: Thripidae).

Abstract

Protected crops like greenhouses and indoor farms using light-emitting diodes (LEDs) allow precise control of light spectrum, intensity, and photoperiod for agronomic purposes. These artificial light conditions also influence insects and arachnids, including predators used in biological control. Despite growing interest, the effects of LEDs on predator behavior and control efficacy remain poorly understood. In microcosm experiments, we studied the locomotion and predation behaviors of the generalist predator Orius insidiosus against thrips (Frankliniella occidentalis) under different light spectra and intensities. We tested narrowband blue, green, and red spectra, 3 blue-red ratios, and a spectrum combining all 3 colors across a light-intensity gradient. Predators attacked prey under all lighting conditions, with 70% of individuals showing predatory behavior during observations. Spectral composition significantly influenced behaviors of interest, while light intensity had negligible effects. Narrowband spectra elicited the highest attack probabilities, but the mixed blue-red spectrum with a higher proportion of red light yielded the highest prey capture rates. The spectrum combining all 3 colors showed intermediate prey capture success. In complex environments with cucumber plants and 24-h artificial light sequences, prey capture probabilities followed similar trends to microcosm experiments. However, thrips survival rates remained similar across all lighting treatments. Our findings suggest that while lighting influences O. insidiosus behavior, this predator remains effective under various conditions, providing a foundation for lighting strategies that balance plant productivity with biological control.