|Chang, Chiou Ling|
Submitted to: International Journal of Tropical Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2013
Publication Date: 11/20/2014
Citation: Resilva, S.S., Obra, G.B., Chang, C.L. 2014. Suitability of a liquid larval diet for rearing the Philippines fruit fly Bactrocera philippinensis (Diptera:Tephritidae). International Journal of Tropical Insect Science. 34(S1):53-58. Interpretive Summary: The Philippines fruit fly Bactrocera philippinensis Drew & Hancock is being reared successfully in the laboratory using an artificial diet. For more than 30 years, a diet based on yellow sweet potatoes and rice bran has enabled the consistent mass production of fruit flies for research, fruit disinfestation treatments and feasibility studies on the sterile insect technique. This formulated artificial diet has sweet potatoes and rice bran as the main ingredients. It contains essential nutrients and serves as a good larval substrate. However, yellow sweet potato is difficult to prepare, expensive, scarce, perishable, and difficult to store for mass production purposes, especially during the rainy season. Rice bran also has some problems associated with handling, procurement and storage, similar to wheat-based bulking agents used in other mass-rearing facilities. The development and adaptation of liquid larval diet technology may solve these problems in fruit fly mass production systems. This new technology is now recommended for rearing some species of Bactrocera and is currently being used in mass rearing of the melon fly Bactrocera cucurbitae at the ARS, USDA, Hawaii. In 2005, a material transfer agreement was signed between the Philippine Nuclear Research Institute and the ARS, USDSA, to evaluate the rearing of B.philippinensis on a liquefied substrate. This agreement included a fruit fly liquid diet starter kit that contained samples of the liquid diet ingredients, rearing materials and a step-by-step diet preparation guide. Preliminary experiments with the original liquid diet starter kit revealed larval growth rates and pupal weight to be comparable to those obtained using the usual artificial diet. This article reports the results of the first attempt made to rear B.philippinensis on a liquid diet. Specifically, the study aimed to (1) replace wheat germ oil with corn oil as an ingredient in the liquid larval diet and (2) evaluate various absorbent materials as a support matrix for feeding larvae.
Technical Abstract: A liquid larval diet as an artificial rearing medium was successfully tested for the Philippines fruit fly Bactrocera philippinensis Drew & Hancock. The biological parameters studied were pupal weight, adult emergence and fliers, sex ratio, fecundity and fertility. The insects performed most satisfactorily if corn (maize) oil was added to the liquid medium. Compared with the standard sponge “Kalle” cloth, three locally available absorbent materials showed promise as a support matrix for feeding larvae.