Predation of Euseius finlandicus on Tetranychus truncatus
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Key Words:Euseius finlandicus, Tetranychus truncatus, predatory function
Abstract:Predation of Euseius finlandicus (Oudemans) on three stages (adult females, nymphs and eggs) of Tetranychus truncatus (Ehara) was examined at five constant temperatures (16, 20, 24, 28 and 32℃) under laboratory conditions with RH 80±5%. Euseius finlandicus was found to prefer eggs and nymphs to adult females of T. truncatus. The predator’s functional response to prey density at these temperatures could be modeled as Holling type Ⅱ. Through the temperature range of 16~28℃, the attack index, the a/Th value and the maximum predatory number all increased with increasing temperature whereas the average treatment time was reduced. The maximum predatory number decreased at temperatures above 28℃. With a fixed number of prey available, predation rate per predator decreased with increasing predator density through mutual competition and interference.