What is haplodiploidy?

• A. A sex-determination system where males develop from unfertilized haploid eggs and females from fertilized diploid eggs
• B. A system where sex is determined by environmental cues
• C. A method of wing development patterns
• D. A reproductive strategy in which males are produced from fertilized eggs

Answer: (A)

Haplodiploidy is a system where sex is determined by chromosome number: males come from unfertilized eggs and are haploid, while females come from fertilized eggs and are diploid. In bees, ants, and wasps, a fertilized egg has two sets of chromosomes and becomes a female, whereas an unfertilized egg has one set and becomes a male. This pattern helps explain why sisters can be more closely related to each other than to their brothers, influencing social behavior in these insects. The other ideas describe different concepts—environmental cues that determine sex, unrelated wing development patterns, or the notion that males arise from fertilized eggs—which do not fit haplodiploidy.