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Comparison of two sterile Mediterranean fruit fly (Diptera: Tephritidae) strains released in California's
James D Barry1, Robert V Dowell, Joseph G Morse
1Department of Entomology, University of California, Riverside 92521, USA. james.barry@ucr.edu
Abstract:
At Mediterranean fruit fly rearing centers, genetic sexing strains such as the male-only temperature sensitive lethal (tsl) strains, are replacing many of the older bisexual strains, such as Maui-93. Three tests were performed to compare the performance of the Vienna-4 (which carries tsl) and Maui-93 strains. Using standard laboratory quality control tests, the Maui-93 strain had higher percent fliers and a lower percentage deformed and partially eclosed flies. Analyses of data from field mark-recapture tests with Jackson traps failed to find significant differences in recapture numbers between the two strains. In field cage survivorship tests, the Vienna-4 strain showed significantly lower mortality in comparison to the Maui-93 strain. These results suggest that although the quality of Vienna-4 flies is lower than Maui-93 at the time of adult emergence, it is comparable with or better than Maui-93 several days later, because weaker flies have been eliminated from the cohort. The benefits of releasing only sterile males, instead of both males and females, was not factored into the quality assessment in this study, but would be an additional benefit in using a strain that carries a tsl mutation.
Insights
New male-only sterile insect strains, like Vienna-4 with temperature sensitive lethal (tsl) mutations, show improved survivorship over older bisexual strains like Maui-93 for Mediterranean fruit fly control.
Area of Science:
- Entomology
- Pest Management
- Genetics
Background:
- Genetic sexing strains, particularly male-only temperature sensitive lethal (tsl) strains, are increasingly adopted in Mediterranean fruit fly (Ceratitis capitata) rearing.
- These strains replace older bisexual strains, such as Maui-93, in sterile insect technique programs.
Purpose of the Study:
- To compare the performance of a tsl strain (Vienna-4) with a conventional bisexual strain (Maui-93) for Mediterranean fruit fly control.
- To evaluate adult emergence quality, field performance, and survivorship between the two strains.
Main Methods:
- Standard laboratory quality control tests were used to assess adult emergence.
- Field mark-recapture tests with Jackson traps evaluated field performance.
- Field cage survivorship tests assessed mortality rates over time.
Main Results:
- Maui-93 exhibited higher percent fliers and fewer deformities upon emergence compared to Vienna-4.
- Mark-recapture tests showed no significant difference in recapture numbers between strains.
- Vienna-4 demonstrated significantly lower mortality in field survivorship tests compared to Maui-93.
Conclusions:
- While Vienna-4 has lower initial adult quality, its later survivorship is comparable or superior to Maui-93 due to the elimination of weaker individuals.
- The use of male-only sterile flies, facilitated by tsl strains, offers additional benefits not quantified in this quality assessment.