(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 signifi cantly 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 signifi cantly 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 fi nite rate of growth (λ) were also signifi cantly (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.

Typhlodromus pyri (Sheuten) (Acari: Phytoseiidae) is a phytoseiid mite with a high potential in controlling the false Chilean mite (Brevipalpus chilensis Baker; Acari: Tenuipalpidae). The purpose of this study was to determine the effect of different plant species pollen as a complementary food in the development of T. pyri when its prey is in low levels of availability. Mites were individually placed on black plastic boxes with pollen and maintained at a temperature of 26 ± 2 °C, 70 ± 5% relative humidity (RH), and a photoperiod of 16:8 h (L:D). Postembryonic development of T. pyri was studied in 11 pollen species, as well as in a mixed diet of Hirschfeldia incana (L.) and B. chilensis. Results show that H. incana was the only pollen in which there was no mortality (P > 0.05) along with the control (Oxalis pes-caprae L.). Mean duration from egg to adult with H. incana was 8.70 ± 1.66 d, protonymph 3.27 ± 0.21 d, and deutonymph 2.90 ± 1.45 d (P > 0.05). The mix feeding of T. pyri did not show any significant differences neither in the mean time from egg to adult, nor in mortality by feeding only with B. chilensis. Survival curves of T. pyri fed only with H. incana pollen, combined with B. chilensis, and only with B. chilensis are higher in the first 14 d of life. The sex ratio was not significantly affected by being fed only with H. incana pollen, B. chilensis, or by a combination of both.