Drone Larvae from Fertilized Eggs of the Honeybee

Abstract

SUMMARY Queens bred for two or three generations by brother-sister matings laid fertilized eggs in worker cells, from which larvae hatched, but only 50% of them survived in the hive. Pieces of worker combs containing eggs laid by these queens were put into an incubator, and the hatched larvae grafted into queen cells on royal jelly and left in the incubator for 24 hours. The sex of these larvae was determined by microscopic anatomical investigations; it could be shown that about 50% of these larvae were male and 50% female. Thus males can develop not only from unfertilized, but also from fertilized eggs; such diploid drones are not seen as adults in the hive, because the diploid drone larvae disappear from the cells within a few hours of being hatched. A new mechanism of sex determination in the honeybee is suggested on the basis of these results: a series of alleles exists at locus X; heterozygotes result in females, but azygotes and homozygotes in males. It is therefore proposed that locus X be called the sex-determining locus, and the alleles at this locus, sex alleles.