Comparative studies of the reproduction-specifity life table on the population of Petrobia latens (Muller) (Acari: Tetranychidae)
Xu Xuenong Xu Weijin (Plant Protection Department)
We studied (1987-88) the reproduction-specifity life table on lab population of Petrobia latens (Muller) that lay two kinds of eggs, and also built 12 groups of life tables at six temperatures. Results are summaried as follows: Temperature had different effects on the life span, number of oviposition of the female laying two kinds of eggs, survival rate, and duration of immature stages. Low temperature greatly prolonged the life span of female laying active eggs, and induced P. latens to lay active eggs; whereas low temperature slightly prolonged the life span of the female laying diapausing eggs, and was unfavorable for P. latens to lay diapausing eggs. Greater influence was on the eggs and larvae than on nymph at the same temperature. At the same stage, parabola relation is assumed between the survival rate and temperature. The γm values of the population laying active eggs were higher than those of the population laying diapausing eggs at all experimental temperatures, that is, the increasing potency of the population laying active eggs was greater than that laying diapausing eggs, and the potency tended to increase as temperature came down.