Preferential attraction of oviposition-ready oriental fruit flies to host fruit odor over protein food odor

Authors: ROH, GWANG HYUN - Oak Ridge Institute For Science And Education (ORISE); Kendra, Paul; Cha, Dong

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2021
Publication Date: 10/6/2021
Citation: Roh, G., Kendra, P.E., Cha, D.H. 2021. Preferential attraction of oviposition-ready oriental fruit flies to host fruit odor over protein food odor. Insects. 12(10). Article 909. https://doi.org/10.3390/insects12100909.
DOI: https://doi.org/10.3390/insects12100909

Interpretive Summary: Oriental fruit fly, Bactrocera dorsalis, is one of the most destructive invasive pests of tropical fruit and vegetable crops worldwide. As a part of research project to develop effective behaviorally-based methods for the detection and control of female fruit flies, researchers at the USDA-ARS laboratories in Hilo, HI and Miami, FL has been investigating the relationship between olfactory preference of female flies and oviposition outcome. In laboratory bioassays using similarly aged (14-16 day old) mated oriental fruit fly females with unlimited protein and sugar diet, some females preferred host fruit odors over protein food odor (torula yeast), while some preferred protein food odor over host fruit odor. Mated females that differed in odor preference exhibited significant differences in egg load and oviposition outcome with females that preferred host fruit odor had 2.1 times greater egg load and laid 2.4 times more eggs than females that preferred protein odor. These results suggest there is an olfactory-based behavioral switch in preference from protein to host odors when female oriental fruit flies are near oviposition. We discuss implications of our findings for practical behavioral management and detection programs for oriental fruit flies.

Technical Abstract: Olfaction plays a key role in the location of food and oviposition resources by tephritid fruit flies. Adult females, including oriental fruit fly, Bactrocera dorsalis, can sustain egg production throughout their lives provided they obtain sufficient protein. Thus, preferential attraction to food or oviposition sites (host fruit) will depend on a fly’s particular physiological state. In this study, laboratory bioassays were conducted with mature, mated B. dorsalis (provisioned protein and sugar ad libitum) to evaluate attraction to traps baited with torula yeast versus six host fruit sources (guava, guava juice, mango, orange, Surinam cherry, or white sapote). Females that preferred fruit laid a significant number of eggs around the trap entrance (average 405 eggs/fly), while almost no eggs were laid by females that preferred yeast (0.5 and 1.3 eggs/fly on two occasions). Similar results were observed in a bioassay using headspace extracts of guava juice and torula yeast, supporting olfactory-mediated responses. When individual females were allowed to oviposit in guava juice traps 0-24 hr after a choice test, 45.8% of females that chose guava juice laid eggs (average 14.7 eggs/fly), compared to 27.5% that chose yeast (average 6.5 eggs/fly). Dissections indicated that females with a preference for guava juice had an egg load 2.4 times greater than females that preferred yeast. These results suggest there is an olfactory-based behavioral switch in preference from protein to host odors when female B. dorsalis are oviposition-ready. We discuss implications of our findings for practical behavioral management and detection programs for B. dorsalis.