Queen breeders improve honey bee stock by deliberately pairing genetic lines. A queen line (left hive) is selected and reared for traits such as Varroa resistance, while a drone line (right hive) is selected for traits like honey productivity. Their genetics are combined — often via instrumental insemination so the cross is fully controlled — to raise an offspring colony (centre) whose workers show a blend of both parents' traits.
Real breeding programmes track Varroa Sensitive Hygiene (VSH) and other resistance markers across generations, similar to the marker-assisted mode here, to raise resistance without the fertility and vigour losses that plague long closed lines.
Two parent bee lines — a Varroa-resistant queen line and a productive drone line — are crossed to raise an offspring colony whose workers visibly blend both parents' traits, with hybrid vigour, inbreeding depression or marker-assisted gains shaping the result.
Offspring colour, glow and mite resistance shift live as you change each parent line's trait strength and the breeding method — hybridisation, closed-line breeding, or marker-assisted selection — showing how genetics and method combine to shape the next generation.
Set queen-line resistance and drone-line productivity, pick a breeding method, and drag the generations slider. Watch the offspring swarm's colour and resistance stat change, and toggle Varroa mite pressure to see resistant stock fend off fewer mites.
Line breeding fixes desirable traits fast but each closed generation raises the inbreeding coefficient (F); real breeders often outcross or use marker-assisted selection to avoid the fertility and vigour losses that come with high F.