Submitted to: Entomological Society of America Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 28, 2004
Publication Date: November 14, 2004
Citation: Allen, M. L. 2004. Fitness Characteristics of Transgenic Strains of New World Screwworm. Entomological Society of America Annual Meeting. Interpretive Summary: Insects such as the Mediterranean fruit fly, the pink bollworm, and the New World screwworm are each used in sterile mass release control programs. All of these insects have been successfully transformed into genetically modified insects that may be used in future control programs. The fitness of these transgenic insect strains for mass rearing needs to be compared with insects currently used for release. A neutral transgene was found to have a negligible fitness cost to genetically modified insects. This is encouraging for future applications of genetic modification technology in insects.
Technical Abstract: Genetic manipulation of insects has matured as a method to a stage at which realistic expectations concerning implementation of transgenic insect control strategies may now be considered. Germ-line transformation methods have been demonstrated in NWS, and eight strains of transgenic NWS were established. Some key issues involved in mass rearing and mass release of sterile insects revolve around fitness. Transgenic insects must be highly productive in mass rearing, and equally capable of surviving and mating with wild insects in order to be truly effective. Modeling and planning mass release strategies can benefit from realistic expectations of fitness costs. Therefore it is critical to analyze fitness characteristics of transgenic insects. The eight transgenic strains of C. hominivorax were compared with the wild-type parental laboratory strain (P95) in culture. Fecundity, fertility, larval biomass productivity, adult emergence, male ratio, and mating competitiveness were analyzed. Overall, the presence of the transgene used to produce the tested strains did not incur a fitness cost to the colonies of laboratory-reared C. hominivorax. Thus it appears that some genetically modified insects may be suitable for mass rearing, and insect program and industries that rely on mass reared insects may consider novel genetic traits for manipulation.