Interactive effects of temperature and controlled atmosphere at biologically relevant levels on development and reproduction of the psocid, Liposcelis bostrychophila Badonnel (Psocoptera : Liposcelididae)

The interactive effects on the development, survivorship and reproduction o f Liposcelis bostrychophila Badonnel, of two biologically relevant controll ed atmosphere (CA) environments 10% CO2 + 5% O-2, and 12%CO2 + 9% O-2 were determined at eight constant temperatures (17.5, 20, 22.5, 25, 27.5, 30, 32 .5 and 35 degreesC) in the laboratory. The life cycle parameters measured u nder nonmodified atmosphere conditions served as a control. A population re ared at 17.5 degreesC failed either to develop or to reproduce regardless o f atmospheric conditions, whereas populations reared under combined conditi ons successfully completed their life cycles. However, development, survivo rship, and reproduction were ail inhibited by hypoxia and hypercarbia compa red with the control atmosphere. Egg development was more sensitive to 12% CO2 than to 10% CO2 exposure. Nymphal development, survivorship, and reprod uction were more sensitive to 5% O-2 (10% CO2) than 9% O-2 (12% CO2). Sensi tivity was evident at higher temperatures. The first and second nymphal ins tars were the most sensitive life stages to CA exposure. We conclude that 1 0-12% CO2 and 5-9% O-2 atmospheres found in sealed storage containers as th e result of respiration of the grain, insect and related organisms, would n ot be effective in the control of L. bostrychophila.