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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Crop and Commodity Protection Research » Research » Publications at this Location » Publication #237736
Title: All male strains and chemical stimulants: Two ways to boost sterile mailes in SIT programs

Author
item McInnis, Donald
item SHELLY, TODD - USDA/APHIS
item MAU, RONALD - UNIVERSITY OF HAWAII

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2008
Publication Date: 4/1/2008
Citation: McInnis, D.D., Shelly, T., and Mau, R. 2008. All male strains and chemical stimulants: Two ways to boost sterile males in SIT programs. Proceedings of the 3rd RCM on improving sterile male performance in fruit fly programmes. April 1-5, 2008, Valencia Spain.

Interpretive Summary: Interpretive summary: Genetic and chemical means have been developed to significantly improve the effectiveness of the sterile insect technique against tephritid fruit flies in recent years. Beginning with the development of genetic sexing techniques some 25 years ago, all-male strains of several species of fruit flies have greatly improved the SIT. Chemical supplements such as ginger root oil for Ceratitis capitata (medfly) males and methyl eugenol for Bactrocera dorsalis males have further increased the field efficiency of released mass-reared sterile males of these 2 species at very limited cost. Natural sources, including plant flowers or stems, have been found to emit compounds that can benefit males of certain fly species. Artificial sources of these same compounds can be used to improve the quality of male flies exposed to them. Laboratory mating improvements to a Hawaii lab strain of OFF were realized several years ago using the known powerful male attractant, methyl eugenol. Mating tests have increased in scale from laboratory mating tests to outdoor field cages, both small and large, and finally to open field releases of sterile males. Wild medfly and oriental fruit fly populations were monitored in open field tests, and host fruits were collected to monitor induced egg sterility in treated and control areas. A new technique based on identifying the sperm differences between sterile and wild sperm has improved the existing standard methods of measuring sterile male fly competitiveness against wild males under field conditions. Both new and old methods have shown that the sterile oriental fruit fly males released in Hawaii are very competitive in the field.

Technical Abstract: Technical abstract: Genetic and chemical means have been developed to significantly improve the effectiveness of the sterile insect technique against tephritid fruit flies in recent years. Beginning with the development of genetic sexing techniques some 25 years ago, all-male strains of several species of fruit flies have greatly improved the SIT. Recently, an all-male pupal color sexing strain for the melon fly, Bactrocera cucurbitae, has been successfully mass-reared then open field tested on several Hawaiian islands demonstrating the high efficiency of this particular genetic sexing strain. Chemical supplements such as ginger root oil for Ceratitis capitata (medfly) males and methyl eugenol for Bactrocera dorsalis males have further increased the field efficiency of released mass-reared sterile males of these 2 species at very limited cost. Natural sources, including plant flowers or stems, have been found to emit compounds that can benefit males of certain fly species. Artificial sources of these same compounds can be used to improve the quality of male flies exposed to them. The first such cases involved the use of methyl eugenol to improve the mating vigor of oriental fruit flies (OFF), Bactrocera dorsalis. Laboratory mating improvements to a Hawaii lab strain of OFF were realized several years ago. Mating tests have increased in scale from laboratory mating tests to outdoor field cages, both small and large, and finally to open field releases of sterile males. Wild medfly and OFF populations were monitored in the open field tests, and host fruits were collected to monitor egg sterility in treated and control areas. Also, the sperm ID technique, developed for medflies initially, has been extended to the OFF and applied to the open field experiment recently conducted on the island of Oahu. Data for both the standard egg hatch from host fruits and the sperm ID method based on captured wild females have been compared to show the effectiveness of the sterile males in an open field situation.