Sperm Production in Tarnished Plant Bugs (Heteroptera: Miridae) Following Irradiation

Abstract

With recent advances that allow their mass rearing, tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), are being considered as subjects for mass sterilization and release. Because sperm production in sterile insects has been cited as an important component of competitiveness, it was measured in irradiated and unirradiated bugs. Bugs subjected to dosages of 5, 10, 20, and 40 krad (50, 100, 200, and 400 Gy) of gamma-irradiation at approximately 7 d post-eclosion to adulthood produced less sperm than untreated bugs. Sperm production was inversely related to dosage. Sperm counts exceeded 1 million per male in the control group and peaked at approximately 600,000 per male in the 5 krad group at day 21 post-eclosion, at approximately 500,000 per male for the 10 and 20 krad groups between days 17 and 21 post-eclosion, and never exceeded half of the control for the 40 krad group, which suffered high mortality in all three replications. Sperm was not seen in newly-eclosed adults, but accumulations averaged 23,000 in 3-d post-eclosion adults and increased to over 100,000 by day 5. Peak counts of 1.6 million were recorded on day 31 post-eclosion.