Varroa destructor mites don't just weaken bees by feeding on them — their real danger is as a vector that spreads viruses like Deformed Wing Virus (DWV) through the colony far faster than the virus could spread on its own. In parallel, worker bees hold the brood nest at roughly 34.5°C using shivering to warm it and fanning or water evaporation to cool it; sustained deviation from that band causes lasting developmental damage. This model runs both threats side by side: mite pressure grows logistically and is suppressed by monitoring/treatment, viral load tracks toward a level set by the current mite population, and brood temperature drifts away from the ideal when thermoregulation effort is low — each pulling colony health down independently.
mite' = growth·mite·(1 − mite/100) − treat·k·mite
virus → target(mite, treat) (eased each frame)
broodTemp = 34.5 + (1 − therm/100)·driftAmplitude
health' = −a·virus − b·|broodTemp − 34.5| + recovery·(100 − health)
- Varroa mite pressure — starting/ambient infestation intensity; higher pressure feeds faster viral spread and direct brood damage.
- Monitoring & treatment — miticide treatment and inspection frequency; suppresses mite growth and slows how much viral load a given mite level produces.
- Brood thermoregulation effort — how tightly workers hold the ~34.5°C brood-nest setpoint; low effort lets temperature drift, damaging brood independently of disease.
- Reset colony — restarts the colony at full health with the current slider settings, so you can compare trajectories.
Real-world relevance: this is why beekeepers treat for mites even in colonies that look healthy — by the time viral symptoms (deformed wings, dying brood) are visible, the underlying mite vector has usually been building for weeks, and a colony's ability to buffer brood temperature is itself an early signal of overall colony strength.