How is sex determined in Honey bee?

Explanation

The mechanism of sex determination has always been a puzzle before the geneticists.
The initial clue about the genetic/chromosomal mechanism of sex determination can be traced back to some of the experiments carried out in insects.
The cytological observation made in a number of insects led to the development of the concept of genetic/chromosomal basis of sex determination
= Henking (1891) could trace a specific nuclear structure all through spermatogenesis in a few insects and it was also observed by him that 50% of sperm received this structure after spermatogenesis, whereas the other 50% sperm did not receive it.
= Henking gave a name to this structure as the X-body but he could not explain its significance.
= Further investigations by other scientists led to the conclusion that the .X-body. of Henking was in fact a chromosome and that is why it was given the name X-chromosome.
= It was also observed that in a large number of insects the mechanism of sex determination is of the Xo type i.e. all eggs bear an additional X-chromosomes (autosomes).
= On the other hand some of the sperms bear the X-chromosome whereas some do not Eggs fertilised by sperm having an X-chromosome become female and those fertilised by sperms that do not have an X-chromosome become males.
= Due to the involvement of the X-chromosome in the determination of sex, it was designated to be sex chromosome and the rest of the chromosomes were named as autosomes.
= Grasshopper is an example of XO type of sex determination in which the males have only one X-chromosome besides the autosomes, whereas females have a pair of Xchromosomes.
= These observations led to the investigation of a number of species to understand the mechanism of sex determination.
= In a number of other insects and mammals including man, X-Y type of sex determination is seen where both male and female have same number of chromosomes.
= Among the males an X-chromosome is present but its counter part is distinctly smaller and called the Y-chromosome.
= Females however have a pair of X-chromosomes.
= Both males and females bear same number of autosomes.
= Hence the males have autosomes plus XY while female have autosomes plus XX.
= In human beings and in Drosophila the males have one X and one Y chromosome, whereas female have a pair of X-chromosomes besides autosomes.

Determination of sex by chromosomal differences: (a,b) Both in humans and in Drosophila, the female has a pair of XX chromosomes (homogametic) and the male XY (heterogametic) composition, (c) In many birds, female has a pair of dissimilar chromosomes ZW and male two similar ZZ chromosomes.