Numerical responses of the predatory mites, Cheyletus eruditus (Trombidiformes: Cheyletidae) and Cheyletus malaccensis, to Liposcelis decolor (Psocodea: Liposcelididae)

Predatory mites display diverse ecological mechanisms to suppress pest population density below certain thresholds known to cause economic loss. The current study explored the numerical responses of the predatory mites, Cheyletus eruditus (Schrank) (Trombidiformes: Cheyletidae) and Cheyletus malaccensis Oudemans, to Liposcelis decolor (Pearman) (Psocodea: Liposcelididae). The numerical responses of these 2 cheyletid mites to nymphs, adult males, and adult females of L. decolor were determined under laboratory conditions at 24 & PLUSMN; 1 & DEG;C, 85 & PLUSMN; 5 RH, and 0:24 (L:D) photoperiod. Oviposition rate, oviposition efficiency, and efficiency of conversion of ingested (ECI) food resources were the key numerical response parameters assessed. The present study revealed a general trend of a strong negative and positive correlation between oviposition rates and increase in prey densities (number of prey per 16.98 cm(2)) for C. eruditus and C. malaccensis, respectively. The oviposition efficiency was mostly similar for both predatory mites and was inversely related to prey density. Generally, ECI (%) decreased considerably with increasing prey density across different prey types for both predators, however, C. malaccensis was more efficient than C. eruditus in utilizing prey biomass. Given the relatively weak numerical responses, we recommended further assessment of these predatory mites before recommending their use for managing stored-product insect pests in the United States.

Automated summary

Predatory mites have diverse ecological mechanisms to control pest population density, but their effectiveness varies. This study examined the numerical responses of two predatory mites, C. eruditus and C. malaccensis, to the prey L. decolor. The oviposition rate, oviposition efficiency, and efficiency of conversion of ingested (ECI) food resources were assessed. The results showed a negative correlation between oviposition rates and prey densities for C. eruditus, while C. malaccensis had a positive correlation. ECI decreased with increasing prey density, but C. malaccensis was more efficient in utilizing prey biomass. Further assessment is recommended before using these predatory mites for stored-product insect pest management in the United States.