The total number of Df(2R)B/l(2)41Aa¹ larval neuroblast cells undergoing mitosis is reduced compared to wild-type cells (mitotic index of 0.2 vs 0.81). The number of l(2)41Aa^IR18/l(2)41Aa¹ cells undergoing mitosis is likewise reduced (mitotic index of 0.5). 10% of l(2)41Aa^IR18/l(2)41Aa¹ mutant larval spermatids carry micronuclei. 4% of l(2)41Aa^IR18/l(2)41Aa¹ mutant larval spermatids have large Nebenkerns associated with either two or four nuclei or micronuclei. In 10% of l(2)41Aa^IR18/l(2)41Aa¹ mutant larval spermatids, bivalents do not condense properly and chromatin filaments are visible along the three major dots of chromatin. In l(2)41Aa^IR18/l(2)41Aa¹ mutant larval spermatids, 15% of chromosomes are seen to be lagging during anaphase/telophase I and 14% lag during anaphase/telophase II.

In heterozygous combination with Df(2R)B dies as late third instar larvae exhibiting one or more large and numerous small melanotic masses in the hemocoel.