Irradiation Effects on Midguts and Testes of the Adult Boll Weevil, Anthonomus grandis, Determined by Histological and Shielding Studies

Abstract

Histological studies demonstrated that radiation doses considerably below those required for sterilization killed most regenerative cells of boll weevils, Anthonomus grandis Boheman, which resulted in the loss of most or all of the secretory epithelium. Extensive damage to midgut was noted in 1 specimen that received 2000 R and in all those given 4000 R. Shielding experiments showed that when only the head and that part of the thorax anterior to the midgut were irradiated, mortality did not exceed that of the control. Irradiation over the abdomen and the posterior part of the thorax produced the same level of mortality as did whole-body irradiation. These findings indicate that damage to the midgut is the basic cause of the high mortality among weevils given sterilizing closes of radiation. At 10 days after irradiation, no spermatogonia were found in any testes irradiated with 6000 R or more, and none were found in some testes that received only 2000 R.