Using harmonic radar to compare movement behavior between Bactrocera dorsalis and Ceratitis capitata (Diptera: Tephritidae).

Abstract

Behavioral differences between related insects may inform how pest management strategies or conservation efforts are tailored to specific species. Movement behavior is particularly important, but few studies have undertaken head-to-head comparisons to evaluate differences in interspecific movement. This study used harmonic radar to simultaneously track 2 agriculturally important tephritid fruit fly species, Bactrocera dorsalis (Hendel) and Ceratitis capitata (Wiedemann), in an outdoor cage (experiment 1) and a coffee field (experiments 2 and 3) to assess fly directional movement, distance, and speed parameters. In general, both fly species have similar movement parameters. However, experiment 2 showed B. dorsalis to be more active with fewer induced movements and less time needed to record the target number of movement steps. This was supported by a laboratory bioassay (experiment 4) that confirmed B. dorsalis were more active. Mean step-distances only differed in experiment 2 and were longer for C. capitata. Experiment 3 tracked tagged flies over time with 2 B. dorsalis located after 3 d post-release while no C. capitata were located after 48 h. Both species generally move with the prevailing wind. While this study found some differences in movement behaviors between these 2 fly pests, fly movement parameters were more similar than expected, suggesting that it may be possible to characterize the movement of key insect species and then generalize these findings to related taxa. If this is possible, control and detection strategies optimized with movement data from one species may be transferable to other pests, thereby increasing the impact of movement research.