Spermatozoan Length in Species of the Drosophila affinis Subgroup

Abstract

Sperm length determinations were made in both XY and XO strains of Drosophila affinis and D. narragansett, neither species of which requires a Y chromosome faT male fertility, and in strains of related D. affinis subgroup species D. algonquin, athabasca (several strains with partial reproductive isolation), D. azteca and tolteca.Each of these species manifested two nonoverlapping "short" and "long" sperm classes.There was no• evidence that presence or absence of a Y chromo:.omeinfluences sperm length in either of the two size classes in D. affinis and D. narragansett.The six different affinis subgroup species failed to diff,er appreciably in the length of their "short" sperms, which overlapped broadly from one species to another with means averaginf!about 0.16 mm.On the other hand, lenf!ths of "long" sperms varied c-onsiderably between sp•ecies; D. affinis had the shortest "long'' sperms, averaging about 0.5 rnm in length, while the longest "lonf!''sperms were found in D. azteca and tolteca, one strain of azteca averaging about 2.08 mm.