|Throne, James - Jim|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2008
Publication Date: 6/1/2009
Citation: Opit, G.P., Throne, J.E. 2009. Population Growth and Development of the Psocid Liposcelis brunnea Motschulsky (Psocoptera: Liposcelididae) at Constant Temperatures and Relative Humidities. Journal of Economic Entomology 102: 1360-1368. Interpretive Summary: Psocids, or booklice, are emerging pests of stored grain and processed stored products, but we know little about their biology and control. We determined that a little studied species, Liposcelis brunnea, will not develop at a relative humidity of 43% or below or above 95 degrees, while populations increased from 72 to 90 degrees and 55 to 75% relative humidity. Population growth was higher at 63% than at 75% relative humidity. The ability of L. brunnea to multiply rather rapidly at 55% RH may allow it to thrive under conditions of low relative humidity where other Liposcelis species may not. These data give us a better understanding of L. brunnea population dynamics and can be used to help develop effective management strategies for this psocid.
Technical Abstract: We investigated the effects of temperature and relative humidity on population growth and development of the psocid Liposcelis brunnea Motschulsky. L. brunnea did not survive at 43% RH, while populations increased from 22.5-32.5°C and 55 -75% RH. Interestingly, we found L. brunnea population growth was higher at 63% RH than at 75% RH, and the largest population growth was recorded at 32.5°C and 63% RH. At 35°C, L. brunnea nymphal survivorship was 33% and populations declined or barely grew. L. brunnea males have two to four nymphal instars, and the percentages of males with two, three, and four instars were 13, 82, and 5%, respectively. Female L. brunnea have three to five instars, and the percentages of females with three, four, and five instars were 18, 78, and 4%, respectively. The life cycle was shorter for males than females. We developed temperature-dependent developmental equations for male and female eggs, individual nymphal, combined nymphal, and combined immature stages and nymphal survivorship. The ability of L. brunnea to multiply rather rapidly at 55% RH may allow it to thrive under conditions of low relative humidity where other Liposcelis species may not. These data give us a better understanding of L. brunnea population dynamics and can be used to help develop effective management strategies for this psocid.