Beyond strain maintenance: Pre-Filter, a viable practice to incorporate desirable traits to genetic sexing strains (GSS) of Ceratitis capitata used in sterile insect technique (SIT) control programs.

Abstract

The sterile insect technique (SIT) for controlling the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), requires the mass-rearing of males in bio-facilities. This study summarizes the implementation of a Pre-Filter system in the mass-rearing process of C. capitata at the Moscamed program's El Pino facility in Guatemala. The Pre-Filter selection process as presented here was aimed to increase the longevity of the VIENNA 8 D53- strain males released for pest control. Over a 9-year period (2015-2024), the longevity of these males was systemically monitored, and the impact of the Pre-Filter system on mortality, half-life, and survival rate were analyzed. Results indicated a significant reduction in mortality at 48 h, declining from 16.47% in 2017 to 2.56% in 2024. Concurrently, the half-life of males increased from 79.55 h in 2018 to 85.97 h in 2024. The Pre-Filter system shifted the frequency distribution of half-lives toward longer durations, with a peak observed between 76.14 and 86.14 h, whereas populations without the Pre-Filter exhibited shorter half-lives, peaking between 56.14 and 66.14 h. Comparative analyses with historical data (2005-2024) demonstrated that the Pre-Filter system significantly improved the male longevity, compared to pre-implementation periods during which mortality rates were higher and more variable. Additionally, the results revealed a gradual reduction in longevity variability within the population, indicating a more homogeneous longevity among the mass-reared males.