The haplodiploid sex-determination system where all the males of the population are haploid and females are diploid, is seen in:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Honey bees
Option (1) Drosophila — Incorrect. In Drosophila, as in humans, sex is decided by the XX-XY system: females are XX and males XY.
Option (2) Honey bees — Correct. A fertilised egg becomes a female (queen or worker) with 32 chromosomes. An unfertilised egg becomes a male (drone) by parthenogenesis, with 16 chromosomes.
Option (3) Birds — Incorrect. In birds the female is ZW and the male ZZ, so the female decides the sex of the young.
Option (4) Grasshoppers — Incorrect. Grasshoppers follow the XX-XO system: females are XX and males have a single X.
NCERT Extract:
Sex Determination in Honey Bee – “The sex determination in honey bee is based on the number of sets of chromosomes an individual receives. An offspring formed from the union of a sperm and an egg develops as a female (queen or worker), and an unfertilised egg develops as a male (drone) by means of parthenogenesis. This means that the males have half the number of chromosomes than that of a female. The females are diploid having 32 chromosomes and males are haploid, i.e., having 16 chromosomes. This is called as haplodiploid sex-determination system and has special characteristic features such as the males produce sperms by mitosis (Figure 4.13), they do not have father and thus cannot have sons, but have a grandfather and can have grandsons.”
Figure 4.13 Sex determination in honey bee