Bees orbit the hive; red dots are varroa mites riding on infested bees. Orange cones are hornets probing the entrance — guard bees (the defense slider) intercept a fraction of them before they can pick off a forager.
dMiteLoad/dt = spreadRate - treatmentEffect * treatment
dPopulation/dt = birthRate - miteLoad*lossFactor - hornetSuccessRate*huntRate
hornetSuccessRate = hornetPressure * (1 - defense)
- Varroa treatment — miticide/IPM effort; directly slows and reverses mite load growth.
- Hornet pressure — how often hornets (Asian/European) probe the entrance.
- Colony defense — guard-bee response strength; strong defense (or hornet-specific tactics like "bee-balling") repels more attacks.
Real colony losses are rarely one cause alone — this mirrors how varroa (as a virus vector) and predator pressure compound, which is why integrated pest management treats them together rather than picking just one intervention.