INFLUENCE OF HUMIDITY ON THE PREDACEOUS MITE MELICHARES DENTRITICUS (BERLESE) (ACARINA : ACEOSEJIDAE)

Abstract

The predaceous mite Melichares dentriticus (Berlese) was reared individually on larvae and protonymphs of the stored food product mite Tyrophagus putrescentiae (Schrank) at 68.0° F and 70, 80, 90, and 100% R.H. Survival and speed of development of the immature stages increased slightly with the humidity. Longevity of adult females was similar at different humidities, though the oviposition period was much shorter at 70% R.H. More eggs were laid at 100% R.H., but then the peak of laying occurred later in the oviposition period. The rate of increase of the predator population was altered very little by different humidities in comparison with that of the prey population and thus, assuming that these rates are an accurate guide to the outcome of the interaction, the population of the prey should be better controlled at lower humidities.