Dietary wheat germ oil and age influences fatty acid compositions in adult oriental fruit flies

Abstract

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is a serious pest of fruit crops in Asia, several Pacific Islands and sometimes the western United States, particularly California. Sterile insect technique programs have been developed for management of several tephritid fruit fly pests. These programs are based on continuous production of adult fruit flies. The high expense of mass-rearing oriental fruit flies drives research to improve the cost effectiveness of rearing programs. One recent improvement for mass rearing oriental fruit flies involves adding wheat germ oil (WGO) to the larval culture medium, which improved several parameters of biological performance. The performance enhancing influence of WGO is due to the presence of polyunsaturated fatty acids (PUFAs), some of which are nutritionally essential for many insect species. We considered the issue of whether WGO supplementation of the larval culture medium influences the fatty acid make up of adult tissues. We report that WGO supplementation led to substantial increases in adult tissue C18 PUFAs. Unlike the outcomes of unrelated nutritional studies on moths, the PUFA components of WGO did not improve adult fruit fly performance. Taken with recent publications reporting that WGO in larval diets influences gene expression, we conclude that dietary WGO improves biological performance of adults through changes in tissue C18 PUFAs and gene expression.