Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2008
Publication Date: 12/15/2008
Citation: Chang, C.L., Mcinnis, D.O. 2008. Evaluation of the Mating Competitiveness of the Adult Oriental Fruit Fly Reared as Larvae in Liquid vs. Those Raised on Standard Wheat-based Diets. Journal of Applied Entomology. 132: 806-811
Interpretive Summary: The oriental fruit fly is one of the most destructive fruit and vegetable pests worldwide. Its existence has caused significant losses in crops as well as marketing opportunities in our global market economy. From 2000-2007, a group of scientists from the USDA-ARS, USDA-APHIS, HDOA, and UH has implemented an area-wide pest management (AWPM) program to suppress tephritid fruit fly populations in Hawaii’s economically and agriculturally important areas. The technologies developed within this program have been transferred to many parts of the world that share similar fruit fly problems. One of the most important components of an AWPM program is to have well established and cost-effective methodologies in place to rear high-quality fruit flies and their parasitoids. USDA-ARS recently developed a liquid diet method for larval rearing of fruit flies and a starter kit has been distributed to interested groups that, so far, have involved participants from 35 countries and 22 species of fruit flies worldwide. Mass rearing for field release will be implemented following the success of the starter kit evaluation. Life history traits from larvae reared on a liquid diet before irradiation and color marking, have been evaluated and reported as satisfactory compared to those of the standard lab strain. However, whether adults reared from larvae on a liquid diet would have the same mating competitiveness in the field after irradiation, color marking and release remains unknown. The objective of this study is to compare the mating competitiveness of adult oriental fruit flies from larvae reared on a liquid diet, mill feed diet (standard lab strain), or papaya host fruit diet (wildish strain), under field conditions including outdoor field cages and Boller’s cages.
Technical Abstract: Three strains (standard lab, DTWP pupal color sexing strain and wild strain) of adult oriental fruit flies, which were reared as larvae on a liquid diet, mill feed diet (Tanaka’s diet), or natural host fruit diet, were evaluated for mating competitiveness in both indoor and outdoor Boller’s mating cages and outdoor field cages. The Relative Sterility Index (RSI) was used as an indicator of mating capability. The RSI between standard strain adults that grew as larvae in liquid diet (LD) and those in Tanaka’s mill feed diet (MF) indicated no statistically significant difference in Boller’s mating cage results after irradiation and dye marking. These results show that irradiation and dye marking had no effect on laboratory mating ability. Adults of the DTWP sexing strain that were reared as larvae in a liquid diet (DTWP-LD) or mill feed diet (DTWP-MF) had a lower mating ability than the standard lab strain in Boller’s cages, and against the wild strain in both Boller’s and field cages. However, there was no statistically significant difference between irradiated DTWP-LD strains in competition with non-irradiated standard lab strain or DTWP-MF strain in Boller’s cages. These findings indicate that: (1) the quality of DTWP may be less capable in mating than the standard lab strain and wild strain; and (2) liquid diet reared larvae can produce adults of equal mating ability compared to adults reared on a conventional diet. Liquid diet reared fruit flies should therefore be ready for mass scale rearing for SIT programs following the completion of other field quality control tests, including those measuring dispersal abilities.