Population growth and development of Liposcelis obscurus Broadhead (Psocodea: Liposcelididae) at constant temperatures and relative humidities: Presentation

Abstract

The effects of nine temperatures (22.5, 25, 27.5, 30, 32.5, 35, 37.5, 40, and 42.5°C) and four RHs (43, 55, 63, and 75%) on the population growth and development of the parthenogenetic Liposcelis obscurus Broadhead (Psocodea: Liposcelididae) were investigated in laboratory studies. Results showed that L. obscurus did not survive at 43% RH at all temperatures tested. At 55% RH, L. obscurus survived at 22.5, 25, and 27.5°C; none survived at 42.5°C and =63% RH. Liposcelis obscurus survived and the population increased 56–fold from an initial population of five adult females at 42.5°C and =75% RH. Population growth was highest at 40°C and 75% RH, where population increase was 215-fold. Liposcelis obscurus has three-to-five nymphal instars, and the percentages of third, fourth, and fifth instars were 52, 41, and 7%, respectively. Temperature-dependent developmental equations were developed for L. obscurus eggs, individual nymphal, combined nymphal, and combined immature stages. Liposcelis obscurus populations grew much faster at 30–42.5oC and 75% RH. These data provide a better understanding of L. obscurus population dynamics, and can be used to develop effective management strategies for this psocid.