Published online by Cambridge University Press: 10 July 2009
Freshly formed (less than 1-day-old) pupae of Stomoxys nigra Macq. treated with gamma rays showed a linear-regression mortality-response with radiation exposure. Mature 5-day-old pupae did not show this effect and were considered more suitable for sterility studies. Flies emerging from both groups of treated pupae showed no deviation from a 1:1 sex ratio. Radiation inhibited fecundity. An exposure dose of 1000 R halved egg production and a dose of 2000 R almost stopped oviposition. Females from pupae exposed to 3000 R produced no eggs. Complete sterility of males was not achieved within the range of tested dosage; exposures of 3000 R and 4000 R induced 98–8 and 99–7% male sterility, respectively. Radiation reduced the longevity of both males and females. A dose of 3000 R did not impair either male mating ability or sexual competitiveness in small-scale laboratory tests.