Effects of chilling, fluorescent dust marking, and X-ray irradiation on the quality of male Anopheles arabiensis for sterile insect technique applications.

Malaria remains a major public health challenge in sub-Saharan Africa, with Anopheles arabiensis an important vector in several regions. Increasing insecticide resistance and flexible vector behavior limit the effectiveness of conventional control measures. The sterile insect technique (SIT) offers a complementary approach through the release of sterile males, with program success dependent on male quality. This study assessed the effects of chilling, fluorescent dust marking, and X-ray irradiation on the quality of laboratory-reared male An. arabiensis. Adult males were assigned to six treatment groups combining chilling, irradiation, and marking in different sequences. Male quality was evaluated through recovery, escape rates, reproductive performance, and longevity under standard insectary conditions. Recovery rates one-hour post-treatment were high across all groups (93.5-96.6%) and did not differ from controls. Escape rate was temporarily reduced at two hours but largely recovered by 24 h, with only chilled and marked males showing persistent impairment. Fecundity and female insemination rates were unaffected by treatment. Fertility remained high in non-irradiated groups and was reduced to < 0.2% following irradiation. Longevity was not significantly affected. These results indicate that male An. arabiensis are resilient to routine SIT handling procedures. Brief chilling followed by irradiation and marking preserves key quality traits, supporting optimized operational protocols for SIT-based malaria vector control.