Potential of harmonic radar system for use on five economically important insects: Radar tag attachment on insects and its impact on flight capacity

Abstract

Harmonic radar tracking system for insects has been introduced to understand insect movement, particularly those which move at low altitudes and over relatively short ranges. Although entomologists have used direct observation and mark-and-recapture techniques as tracking methods, there are drawbacks such as low recapture rates in the case of marking techniques. The objective of this study was to quantitatively examine adhesive bond strength between radar tag and insect body and to evaluate the effect of tag attachment on flight behavior and capacity of five economically important insect species, including three pest species, Riptortus pedestris (Hemiptera: Alydidae), Lycorma delicatula (Hemiptera: Fulgoridae), and Ricania sp. (Hemiptera: Ricaniidae) and two pollinators, Apis mellifera (Hymenoptera: Apidae) and Bombus terrestris (Hymenoptera: Apidae). The adhesive bond strength was substantially different among these five insect species, but the strength was sufficiently strong for operational use in harmonic radar tagging except in Ricania sp. Bond strength on B. terrestris was 817±43.65g-forces, which was the strongest among the five species tested, while that on Ricania sp. was 1.7±0.20g-forces, which was the weakest. For all insects, no significant correlation between bond strength and insect body size was observed. The radar tag attachment affected the flight behavior and capacity of five insect species in different ways. The radar tag attachment did not significantly affect the propensity of R. pedestris, L. delicatula, or B. terrestris to takeoff compared to untagged individuals. However, the takeoff propensities of A. mellifera and Ricania sp. were negatively affected by the radar tag attachment. Flight capacities of R. pedestris, A. mellifera, and B. terrestris were not affected by the tag attachment compared to untagged individuals, but the flight capacity of Ricania sp. was negatively affected by the tag attachment. The results of this study indicate that the radar technique has promising potential for R. pedestris, L. delicatula, and B. terrestris. However, this technique may have limited potential for A. mellifera and Ricania sp. because the radar tag can significantly affect their flight behavior.