The effect of temperature and relative humidity on population growth of three Liposcelis species (Psocoptera: Liposcelidae) infesting stored products in tropical countries

Abstract

The effect of a range of temperatures (15–42°C) and relative humidities (40–80%) on growth of populations of Liposcelis entomophilus (Enderlein), Liposcelis bostrychophilus Badonnel and Liposcelis paetus Pearman infesting a rice-based medium was investigated. These species are often found infesting stored cereal grains in the tropics. Both L. entomophilus and L. bostrychophilus bred most rapidly at 30°C, 70–80% r.h. Neither survived at temperatures of 36°C and above. In contrast, L. paetus bred most rapidly at 33–36°C, 70% r.h., and was able to breed at 42°C, 80% r.h. No species survived humidities below 60%. As well as consuming mould growth, Liposcelis spp. also caused visible damage in rice grains. Implications of these findings in the understanding of pest status and geographical distribution of severe outbreaks of Liposcelis spp. are discussed.