Biological characteristics and life tables of Neoseiulus umbraticus Chant (Acari, Phytoseiidae) at three constant temperatures

Abstract

The development time, survival and fecundity of the generalist predatory mite, Neoseiulus umbraticus Chant, were determined at 20, 25, and 30 °C and 65 ± 10 % RH. N. umbraticus females completed development in 9.7, 8.0 and 5.9 days, respectively, using a diet of all life stages of Tetranychus cinnabarinus Boisduval. Total developmental times of males were relatively shorter at 25 and 30 °C than at 20 °C. In general, preoviposition, oviposition, and postoviposition periods of N. umbraticus shortened as temperature increased. The longest survival rate of N. umbraticus of 80.5 days occurred at 20 °C, followed by 67.0 and 57.6 days at 25 and 30 °C, respectively.

Mated females laid an average 0.9, 1.3 and 1.4 eggs per female per day and 33.1, 44.0 and 43.6 eggs over their entire lives at 20, 25 and 30 °C, respectively. The sex ratios of this species were 0.57, 0.57 and 0.54 female (female+male) at 20, 25 and 30 °C, respectively. The intrinsic rate of increase (r_m) became greater with rising temperatures from 0.123 at 20 °C to 0.180 at 30 °C. The net reproduction rate (R_o) was highest at 25 °C (25.0 females/female) and lowest at 20 °C (18.8 females/female), while T_o decreased with increasing temperatures, from 23.8 days at 20 °C to 17.5 days at 30 °C.