Predation of Amblyseius longispinosus (Acari: Phytoseiidae) on Aponychus corpuzae (Acari: Tetranychidae)

Aponychus corpuzae is a pest of bamboo in Fujian, China. The predatory mite Amblyseius longispinosus was explored as a potential biocontrol agent against Ap. corpuzae in a series of experiments on its predation on Ap. corpuzae. The rate of prey consumption (per predator female) increased linearly with temperature from 1.35 at 15°C to 5.22 at 35°C (the relationship can be described by Y = -1.005 + 0.185 T; R = 0.96), whereas the rate of oviposition increased with temperature from 0.11 at 15°C to 3.58 at 30°C and then decreased to 2.27 at 35°C [the relationship can be described by Y = 0.141 (T-30)2 + 43]. The rate of predation increased linearly with prey density within the range of 1-9 prey per leaf (Y = 0.805 + 0.418 X, R = 0.96) and reached a plateau at the density of 9 prey per leaf, but the rate of oviposition increased linearly with prey density Y = 0.955 + 0.380 X (R = 0.97). As expected, the number of eggs laid by predators increased linearly with the number of prey they consumed (Y = 0.290 + 0.423 X; R = 0.93); on average, a predator consumed 1.3-2.5 prey to lay 1.0-1.5 eggs. Functional responses of predator to prey density at five different temperatures (15, 20, 25, 30 and 35°C) and to different active life stages of spider mites (larva, protonymph, deutonymph, adult female and adult male) approximated Holling type II. Amblyseius longispinosus was considered more effective against spider mites at 25°C than at other temperatures. They are most effective against adult female spider mites but least effective against spider mite larvae. With a fixed number of prey available, predation rates per predator decreased with predator density. Aponychus corpuzae adults were observed to show defensive behaviour against predators at high prey densities.