ISOLATION AND CYTOGENETIC ANALYSES OF GENETIC SEXING STRAINS FOR THE MEDFLY, CERATITIS-CAPITATA

Over the last 10 years, several genetic sexing strains have been isola ted for the Mediterranean fruit fly, Ceratitis capitata, with the aim of improving the Sterile Insect Technique. However, a major problem wi th the currently used genetic sexing system, which is based on translo cations, is their potential genetic instability. Therefore, careful mo nitoring and chromosome analyses are necessary when new genetic sexing strains are developed. Instability of a genetic sexing strain can be the consequence of recombination or the survival of aneuploid individu als occurring as a consequence of adjacent-1 segregation in the meiosi s of males with Y-autosome translocations. Recently, genetic sexing st rains have been isolated that show only low levels of recombination. H owever, many aneuploid flies are produced by these strains. Therefore, we have made an attempt to isolate new genetic sexing strains that sh ow a low percentage of recombination and no survival of aneuploid indi viduals. We report their genetic behaviour and the polytene chromosome structure of these new strains.