Effect of thermal acclimation and prevailing conditions on the response of adult Mediterranean fruit flies to traps

Abstract

Trapping seems to be the main tool for detecting insipient Mediterranean fruit fly (medfly), Ceratitis capitata (Diptera: Tepritidae), populations and monitoring population dynamics. The performance of the different trapping systems may be related to prevailing environmental conditions and the physiology of the target insect. In the frameworks of the Horizon 2020 “818184 FF-IPM” program, we explored the effect of adult thermal acclimation and the effect of prevailing climatic conditions on captures of adult medflies in traps under semi field conditions. For this purpose, Tephri traps baited with Biolure were placed individually in five field cages (2.9m Ø x 2m h) housing one potted citrus tree. Five days-old adults, marked at the pupal stage with different colors of a nontoxic fluorescent powder depending on the treatment, were either acclimated to three constant temperatures (15, 25 and 30°C) or maintained in outdoor conditions for five consecutive days. On a test day, ten individuals of each sex and treatment were released, in each field cage. Trap captures were recorded at hourly intervals. Captured adults were examined under a stereoscope using ultraviolet light to determine marking color. The experiment took place in spring (12.1 – 17.8 o C range of average temperatures) and summer (30.6 – 35.3 o C). Our results revealed that prevailing climatic conditions had the most significant effect on the adult captures. Acclimation was significant only in summer while sex affected adult captures only in spring. We discuss the importance of these findings for detecting low C. capitata populations.