Factors affecting detection and trapping efficacy of Mediterranean fruit flies

Adult trapping is essential for detecting, monitoring, and controlling fruit fly pests (Diptera: Tephritidae), its efficacy depends on both biotic and abiotic factors. Although efficient commercial trapping systems exist, capturing major invasive tephritid pests remains challenging. This study investigated whether sex, thermal history, trap location, and climatic conditions affect the trapping efficacy of Mediterranean fruit fly (medfly) adults. Four release-recapture trials were conducted with marked adults (9600 in total) acclimated at 15, 25, 30 °C or maintained in outdoor conditions: two early in spring and two in summer. Plastic McPhail-type and Jackson traps baited with Biolure and trimedlure dispensers, respectively, were placed on either non-host (olive trees) and host (Citrus) trees. Adults were released 2-3 m from each trap.

Acclimation, ambient temperatures, and host plants' presence influenced recapture rates, which were 25.5 and 25.8% for males and 3.0 and 7.4% for females in non-host and host trees, respectively. Higher recapture rates were observed in adults acclimated at lower temperatures or kept outdoors. Trap placement on host plants also improved trapping efficacy. The higher the ambient temperature the higher the recapture rates.

Overall, our results demonstrate that trapping efficacy of medfly and probably other fruit flies is influenced by biological and environmental factors, with ambient conditions being the one with the stronger effect. Cold acclimation like early spring may overestimate population size, while late-season trapping may underestimate it. Hence, thorough examination and careful interpretation of trapping data are crucial for accurate population assessments and for determining detections of invasive pests. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.