Biological parameters of Cydnodromus picanus and Phytoseiulus persimilis raised on the carmine spider mite, Tetranychus cinnabarinus (Acari: Phytoseiidae, Tetranychidae)
The postembryonic development, consumption and life table parameters of Cydnodromus picanus Ragusa and Phytoseiulus persimilis (Athias-Henriot) were studied at 29.44 ± 1.47 °C and 42.35 ± 5.01% of RH with a photoperiod of 14:10 h (L:D) in order to evaluate the potential of these predators for feeding on the carmine spider mite Tetranychus cinnabarinus (Boisduval). Eggs, larvae and protonymphs of T cinnabarinus may be optimal food for C. picanus, which obtained survival rates of 100%, 97% and 93%, respectively, on them. The survival of P persimilis was around 6.7% with diets based on eggs, larvae and protonymphs, showing a high mortality level by dehydration when fed with eggs. The time of the postembryonic development was significantly shorter (p < 0.05) for C. picanus than for P persimilis when they were fed with eggs, larvae and deutonymphs of T cinnabarinus. When fed with eggs and a combination of different stages of T cinnabarinus, the intrinsic rate of growth (r m) was significantly higher (p < 0.05) for C. picanus (0.289 and 0.307, respectively) than for P. persimilis (0.019 and 0.025, respectively). The values of the imite rate of growth (r m) were also significantly (p < 0.05) higher for C. picanus (1.34 and 1.36) than for P persimilis (1.02 and 1.03) when they were nourished with eggs and a mixed diet, respectively. The high values of r m and λ found for C. picanus in the experimental conditions are indicators of the possible control that this phytoseiid mite, as a predator of T cinnabarinus, would potentially offer under the conditions of lower relative humidity encountered in the arid zone of the desert of Chile.