Tracking and modeling the movement of Queensland fruit flies, Bactrocera tryoni, using harmonic radar in papaya fields

Authors: HURST, A - Eastern Mennonite University; O'BRIEN, A - Bridgewater College; MILLER, N - Eastern Mennonite University; WELTY PEACHEY, A - Eastern Mennonite University; YODER, J - Eastern Mennonite University; DE FAVERI, STEFANO - Department Of Agriculture And Fisheries; CHEESMAN, J - Department Of Agriculture And Fisheries; Manoukis, Nicholas; SIDERHURST, M - Eastern Mennonite University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2024
Publication Date: 7/30/2024
Citation: Hurst, A., O'Brien, A., Miller, N.D., Welty Peachey, A.M., Yoder, J.M., De Faveri, S.G., Cheesman, J., Manoukis, N., Siderhurst, M.S. 2024. Tracking and modeling the movement of Queensland fruit flies, Bactrocera tryoni, using harmonic radar in papaya fields. Scientific Reports. 14. Article 17521. https://doi.org/10.1038/s41598-024-67372-4.
DOI: https://doi.org/10.1038/s41598-024-67372-4

Interpretive Summary: In this study we were able to track the movement of individual fruit flies (Queensland fruit fly), which is a major horticultural pest. We accomplished this by attaching a small (8 mg) diode plus an antenna to individual flies and then locating them with a handheld harmonic radar device. We found that individual flight distances ranged from 7.7 to 75.7 m with a mean of 3.0 ± 0.3 m in a papaya field. We also found two classes of movements: One short-distance (usually within a tree) which had random directions and another set that were longer distance (over 2.5m; between trees) and had a particular direction for each fly. Results from this study will enhance models of fruit fly movement to improve management and responses to incursions by this species.

Technical Abstract: Tephritid fruit flies, such as the Queensland fruit fly (Qfly), Bactrocera tryoni, are major horticultural pests; there are recurring incursions around the world due primarily to international trade. Determining movement parameters for fruit flies is critical to developing models can be used to increase the effectiveness of surveillance and control strategies. In this study, harmonic radar (HR) was used to track wild-caught male Qflies in papaya fields in two experiments. Experiment 1 continuously tracked single flies which were prodded to induce movement. Movement path distances (10-12 steps) ranged in length from 7.7 to 75.7 m with a mean step-distance of 3.0 ± 0.3 m. Seven out of twenty tagged Qflies in Experiment 1 showed strong flight directional biases similar to previous tracking results with Zeugodacus cucurbitae. Experiment 2 identified individual landing locations, twice a day, for a group of released Qflies, tracking the displacement of flies over longer periods of time. Observed Qfly movements showed greater mean squared displacement than that predicted by both a simple random walk (RW, i.e., Brownian) or a correlated random walk (CRW) model suggesting that movement parameters derived from the entire data set do not adequately describe the movement of individual Qfly at all spatial scales or for all behavioral states. This is supported by both the observation of lower fractal dimensions (straighter movement paths) at larger spatial scales (> 2.5 m). A two-state hidden Markov model fit the observed movement data better than the CRW or RW models. Data on flight directionality and step-distances determined in this study provide parameters for models which may help enhance current surveillance, control, and eradication methods, such as optimizing trap placements and pesticide applications, determining release sites for parasitoids, and setting quarantine boundaries after incursions.