Effect of spatial scale and prey density on predation of the adult Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) by adult Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

Author of the article:HUANG Zhen-Dong1** ZHOU Xin-Miao2 PU Zhan-Xu1 HU Xiu-Rong1 DU Dan-Chao1 CHEN Guo-Qing1 ZHANG

Author's Workplace：1. Institute of Citrus Research, Zhejiang Academy of Agricultural Sciences, Taizhou 318020, China; 2. Institute of Urban and Horticultural Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China

Key Words： Harmonia axyridis (Pallas); Diaphorina citri; spacial size; prey density; predatory behavior

Abstract：[Objectives]  To provide a reference on the effect of spatial scale and prey density on the effectiveness of adult Harmonia axyridis ( Pallas) as a biological control for adult Diaphorina citri. [Methods]  We investigated the effect of spatial scale on predation by measuring predation in different sized enclosures, and quantified the effect of prey density on the functional response of adult H. axyridis preying on adult D. citri. [Results]  A negative, linear relationship between enclosure size (x) and daily prey consumption (y) could be described by the equation y = -28.375x + 130.08. The HollingⅡ functional response curve indicated that the predation rate increased with prey density. Initial prey density strongly affected the number of prey consumed on the first day, but had only a slight effect on subsequently daily consumption. [Conclusion]  Spatial scale and prey density significantly affect the predation rate of adult H. axyridis on adult D. citri.