Effects of temperature on demographic parameters of bryobia praetiosa (Acari: Tetranychidae)

Abstract

The clover mite, Bryobia praetiosa Koch (Acari: Tetranychidae), is an agricultural pest, as well as a frequent invader of hospitals and homes. However, its adaptability to different temperatures is not well understood. We used age- and stage-specific life tables to investigate the effects of temperature on demographic parameters of B. praetiosa from 15 to 35°C under a long-day photoperiod (16:8 [L:D] h). The clover mite is a thelytokous species (consisting of only females) due to its infection with the symbiotic bacterium Wolbachia. The egg-to-adult development time of female B. praetiosa decreased as the temperature increased from 15 to 32.5°C. At 35°C, females laid eggs, but no eggs hatched. The lower thermal threshold (t) and the thermal constant (K) for egg-to-adult females were 8.7°C and 274.1 degree-days, respectively. The intrinsic optimum temperature (TØ) was 22.4°C. The oviposition period decreased with increasing temperature. Fecundity was highest at 20°C and extremely low at 30°C. The net reproductive rate (R0) decreased as the temperature increased from 15 to 30°C, but no significant difference was observed between 15 and 20°C. The intrinsic rate of natural increase (r) varied from 0.0721/d at 15°C to 0.1679/d at 25°C, and then decreased to 0.1203/d at 30°C. These results should be useful in developing management strategies for B. praetiosa.