Infrared thermography for insect detection: lighting up the spotted lanternfly in the field.
Unlike fireflies and other bioluminescent organisms, lanternflies (Insecta: Hemiptera: Fulgoridae) do not produce visible (400-700 nm) lights as their common name might suggest. However, they can be captured by thermal cameras at long wavelength infrared (8-14 μm). In this study, we tested infrared thermography as an innovative way to detect spotted lanternfly, Lycorma delicatula (White), a newly discovered invasive plant pest in North America, in the field. Using two different infrared cameras, adult L. delicatula on various bark surfaces in the field were detected. Significant temperature gradients were observed for different body parts, resulting in images showing exceptional morphological details at high magnification on the head, thorax, legs, and wings. Detection rate differed significantly between times of observation, ranging from 41.8% at 4:30 am to 33.2% at 7:00 am, and eventually dropped to 7.5% by 7:30 am. No significant difference in detection rate was found between thermal cameras. We suspect that active feeding and rapid hemolymph circulation in adults are responsible for their detection by infrared thermography. This breakthrough discovery could revolutionize early detection and rapid response strategies in spotted lanternfly management. Applications of infrared thermography in the field of entomology and the potential mechanism behind the lighting up of L. delicatula adults are discussed.