Chromosome Aberrations Induced by TEPA-an alkylating Chemosterilant in Spermatocytes of Callosobruchus chinensis Linn. (Coleaptera, Bruchidae)

Abstract

Different doses of TEPA administered to newly emerged or 24 hour old weevils by fumigation method have shown various abnormalities in spermatocyte chromosomes after different time intervals. Most of the effects of this alkylating chemosterilant have been found to be gross or physiological effects involving all the chromosomes of a nucleus, like stickiness, stretching, unequal segregation, clumping etc. Only at few stages with high doses of TEPA, individual chromosomes were affected showing anomalies like bridges and laggards etc. 2-3μl TEPA also showed coiling of sperms. It is assumed that TEPA has a non-delayed (driect) type of effect which kills some sperms and incapacitates others by making them abnormal and nonmotile. The mode of action has been discussed.