Oversummering of eggs of Halotydeus destructor Tucker (Acari: Penthaleidae): diapause termination and mortality.

Diapause termination and mortality were examined in oversummering eggs of 'H. destructor' collected from two pasture sites near Leeton, New South Wales, which differed in soil type and drainage. The effect of soil type and moisture on these factors was also investigated experimentally. Diapause termination was less reliable and mortality higher in eggs obtained from poorly drained clay than from well drained sandy loam. Soil type and moisture did not affect timing or extent of diapause termination. However, moisture increased mortality. Mortality of eggs on permanently wet sand was significantly greater than in any other treatment. The results from this study indicate that summer rainfall can have a deleterious effect on survival of oversummering eggs of 'H. destructor', particularly on heavy poorly drained soils.