🧬 Honey Bee Genetics Lab

About this simulation

Honey bees have haplodiploid sex determination: unfertilised eggs develop into haploid drones (males, one set of chromosomes), while fertilised eggs are diploid and normally develop into female workers or queens. But femaleness itself depends on a single gene, csd (complementary sex determiner) — a diploid egg only becomes a female if its two csd alleles differ. A queen also mates with many drones in flight (polyandry), so her colony is a patchwork of half-sister patrilines, each fathered by a different drone.

How it works

• Patrilines — each colour on the comb is a group of half-sisters sharing the queen but a different father. More mating partners means more patrilines and more genetic diversity for disease and task resilience.
• Diploid drones / "shot brood" — when the queen and a drone happen to share a csd allele (more likely in inbred, low-diversity stock), fertilised eggs become diploid males instead of females. Nurse bees detect and eat these larvae, leaving the tell-tale pitted, patchy "shot" brood pattern.
• Selective breeding — breeders instrumentally inseminate queens with semen chosen for traits like Varroa-sensitive hygiene, pushing the resistant-trait frequency up generation by generation while trying to keep enough drone diversity to avoid the inbreeding trap above.

Controls

• Drones the queen mated with — sets how many patrilines make up the colony (real queens typically mate with ~12–20 drones).
• Colony inbreeding level — raises the chance any given patriline shares a csd allele with the queen, increasing diploid-drone loss.
• Varroa-resistance selection strength — how hard a breeder selects for the resistance trait each generation.
• Show patrilines — toggle patriline colouring on/off to see the comb by trait status instead.
• ↻ Breed next generation — advances one breeding cycle, applying selection to the resistance trait. ⟳ Reset colony restarts from generation zero.

Did you know?

Because drones are haploid, all the sperm a single drone produces is genetically identical — his daughters (a patriline) are full sisters sharing 100% of their paternal genes, making them more related to each other than human full siblings are.