Development, Survival, and Reproduction of the Psocid <I>Liposcelis paeta</I> (Psocoptera: Liposcelididae) as a Function of Temperature

Abstract

The development, survival, and reproduction of Liposcelis paeta Pearman (Psocoptera: Liposcelididae), an important insect pest of stored products, were evaluated at nine constant temperatures (20-40 degrees C). Few insects could complete the development or reproduce at 20 or 40 degrees C. Between 22.5 and 37.5 degrees C, the developmental period from egg to adult varied from 45.4 d at 22.5 degrees C to 11.5 d at 37.5 degrees C. The lower temperature developmental thresholds were estimated at 18.1-21.9 degrees C, and the upper temperature thresholds were 40.4-42.0 degrees C. The percentage of survival from egg to adult was 52.79% at 32.5 degrees C and 18.79% at 22.5 degrees C. After emergence, the adult had a short preoviposition period that ranged from 6.3 d at 22.5 degrees C to 0.8 d at 37.5 degrees C. L. paeta produced the most eggs at 27.5 degrees C and the fewest at 37.5 degrees C. The population reared at 32.5 degrees C had the highest intrinsic rate of increase compared with the other temperatures. Based on our data, the optimal range of temperature for L. paeta population growth was 30-35 degrees C. These data give us better understanding of L. paeta population dynamics, and they can be used to develop effective management strategies for this psocid.

Effects of Constant Temperatures on Reproductive Parameters of the Psocid Liposcelis rufa (Psocoptera: Liposcelididae)

“…Decline in oviposition period with temperature has also been shown in L. reticulatus [23], where this parameter increased from 79% at 22.5°C to 85% at 32.5°C and declined to 75% at 35°C. Similar results have been demonstrated for L. badia [24], L. decolor [26], and L. paeta [27]. The longest-lived L. rufa individual lived for 412 d at 22.5°C, which is exceptionally high when compared to the longevity of other psocids.…”

“…Even at suboptimal temperatures for intrinsic rate of population increase, the potential for L. rufa population growth was higher than that of some of the aforementioned Liposcelis spp. Besides the fact that these psocids belong to different species, other possible reasons for lower intrinsic rates of increase in L. badia [24][25][26][27][28][29] may be that mothers of females in these studies were not of a standardized age, females used were reared from eggs at constant temperatures used for the experiments, and diets were different from those used in the present study and the L. reticulatus study [23].…”

“…If the intrinsic rate of increase at 32.5°C is considered the optimal fitness of 1, then the fitness of L. rufa at 22.5, 25, 27.5, 30, 35, 37.5, and 40°C equals 0.39, 0.53, 0.73, 0.90, 0.88, 0.87, and 0.75, respectively. Highest intrinsic rates of increase for L. reticulatus [23], Liposcelis badia Wang, Wang, and Lienhard [24], L. bostrychophila [25], L. decolor [26], L. paeta [27], Liposcelis tricolor Badonnel [28], and Liposcelis yunnaniensis Li and Li [29] occurred at 32.5, 27.5, 30, 32.5, 32.5, 30, and 35°C, respectively. Intrinsic rates of increase at these temperatures were 0.128, 0.0455, 0.0946, 0.0609, 0.0542, 0.0367, and 0.0554, respectively.…”

“…decolor [26,31], L. paeta [27,31], and L. yunnaniensis [29] are the only other psocid species reported to be adapted to higher temperatures. In the present study, we found that the intrinsic rate of increase, fecundity, and longevity of L. rufa are greater than those of L. decolor, and L. paeta at higher temperatures [26,27]. For example, at 37.5°C, the intrinsic rate of population increase, fecundity, and longevity for L. decolor and L. paeta are 0.0112, 17.8, and 27; and 0.0504, 20.5, and 25, respectively; whereas the values of these parameters for L. rufa are 0.155, 44.4, and 38 d, respectively.…”

Distribution of psocids (Psocoptera) in temperature gradients in stored wheat

“…Liposcelis bostrychophila and L. entomophila can develop from egg to adult at 20 C (Wang et al, 1998(Wang et al, , 2000, but L. paeta cannot (Wang et al, 2009). One would expect that cold-blooded organisms would prefer locations that would be more favorable for development of their progeny, and psocids, which are highly mobile, would be expected to adjust their location in a grain mass to find habitats more suitable for reproduction and development of their progeny.…”