Spider (Araneae) predations on white-backed planthopper Sogatella furcifera in subtropical rice ecosystems, China

BACKGROUNDSpiders are effective biological control agents in rice ecosystems, but the comparative study of predations among main spider species under field conditions has not been fully explored owing to a lack of practical methodology. In this study, more than 6000 spiders of dominant species were collected from subtropical rice ecosystems to compare their predations on Sogatella furcifera (Horvath) (white-backed planthopper, WBPH) using DNA-based gut content analysis. RESULTSThe positive rates for all spider taxa were closely related to prey densities, as well as their behaviors and niches. The relationships of positive rates to prey planthopper densities for Pardosa pseudoannulata (Boes. et Str.), Coleosoma octomaculata (Boes. et Str.), Tetragnatha maxillosa Thorell and Ummeliata insecticeps (Boes. et Str.) under field conditions could be described using saturated response curves. Quantitative comparisons of predations among the four spider species confirmed that P. pseudoannulata and C. octomaculata were more rapacious than U. insecticeps and T. maxillosa under field conditions. A comparison of ratio of spiders to WBPH and positive rates between fields revealed that biological control by spiders could be effectively integrated with variety resistance. CONCLUSIONGeneralist spiders could follow up WBPH population timely, and assemblages of spiders coupled with variety resistance could effectively suppress WBPH population. (c) 2016 Society of Chemical Industry