LIFE-HISTORY STUDIES ON SCHIZOTETRANYCHUS-CELARIUS (BANKS) AND APONYCHUS-CORPUZAE RIMANDO AS COMPARED WITH OTHER TETRANYCHID MITE SPECIES (ACARINA, TETRANYCHIDAE)

Studies on the life history of Schizotetranychus celarius (BANKS) and Aponychus corpuzae RIMANDO, infesting dwarf bamboo leaves, were carried out under laboratory conditions of 25±1°C, 50-60% RH and 15L-9D. The periods from the egg stage to reproductive maturity in these species were longer than those of three species investigated previously (SAITÔ, 1979a), the prolonged oviposition and extended longevity being especially remarkable. S. celarius had a characteristic reproductive pattern, i.e. a long ovipositional period with a rather constant, low reproductive rate. The reproductive pattern of A. corpuzae was intermediate between those of T. urticae and S.celarius. High proportions of females, 83.7%-88.4% in S.celarius and 58 9%- 76.7% in A. corpuzae were usually observed. S. celarius had a net reproductive rate (R0) of 67.60, whereas that of A. corpuzae was 53.84. The intrinsic rate of natural increase (rm) was 0.162 per day for the former species and 0.181 per day for the latter. Consequently S. celarius had a mean generation time (T) of 26.01 days, that of A. corpuzae being 22.02 days. The life history pattern of S. celarius is considered to be correlated with its specialized defence mechanism in its stable habitat. That of A. corpuzae might also possibly be correlated with its life habits and the habitat stability. © 1979, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.