Large Aperture Optoelectronic Devices to Record and Time-Stamp Insects’ Wingbeats

Abstract

Recording and analysis of wildlife sounds with regard to monitoring biodiversity are a developing trend in ecology. Automatic audio-based units are commonly used to record field vocalizations of birds, bats, cetaceans, and amphibians. The wingbeat of insects produces audible but feeble tones. Practical automatic recording units for the wingbeat of insects are still pending. In this paper, we present a complete system to record the wingbeat of insects based on the large aperture optical sensors that turn the light fluctuations (caused by the partial occlusion of light from the wings) into sound. Wide apertures are useful when tracking the movement of fast flying insects and the full motion of the beating wing in the case of tethered insects. The system detects a wingbeat event, auto-triggers the recording process, time-stamps the event, and stores the permanent record in situ. When the sensor is inserted in an insectary, it effortlessly produces massive datasets of wingbeat recordings. We discuss the implications for novel studies that are impractical to carry out manually, as they involve large numbers of insects. We also suggest potential applications such as smart insect traps that count, recognize, and alert for the presence of insects of economic and public health importance.