Reevaluation of the Humidity Requirements of the House Dust Mite Dermatophagoides Farinae (Acari: Pyroglyphidae)

Partially dehydrated female house dust mites, Dermatophagoides farinae , regained water from unsaturated ambient air at 0.55 av (55% rh) and 15 °C, 0.65 av (65% rh) and 25 or 30 °C, and 0.75 av (75% rh) and 35 °C. Mites continued to lose water at each of the above temperatures when av was reduced 0.10 av (10% rh). The critical av for the temperature range 15–35 °C ranges between 0.55 and 0.75 av and is proportional to temperature. All mites died in less than 24 h at 40 °C and 0.85 or 0.95 av.