Abstract: The objective of this study is to investigate the potential of Arma chinensis in predation of the eggs of the invasive pest, Spodoptera frugiperda, and to determine the predation preference for egg age. To this end, the female, male adults and the 5^th instar nymphs of A. chinensis were confined to S. frugiperda eggs 12—24 h, 24—36 h and 36—48 h old. The results indicated that the predation on S. frugiperda eggs by A. chinensis increased gradually with increasing prey density and then stabilized; the functional response fitted well with the Holling II model. Male adults of A. chinensis had the highest predation efficiency, followed by the 5^th instar nymphs, while female adults had the lowest. The daily predation by the 5^th instar nymphs, female and male adults of A. chinensis to S. frugiperda eggs 24—36 h, 36—48 h and 12—24 h old was the highest, which was 53.2, 26.7 and 52.6 eggs, respectively. In summary, the 5^th instar nymphs and the male adults of A. chinensis are more effective in controlling 12—24 h and 24—36 h S. frugiperda eggs. However, for field release, it is preferable to release the 5^th instar nymphs of A. chinensis. The results of this study provide an important reference for the use of A. chinensis in control of S. frugiperda.

Key words: biological control, functional response, Arma chinensis, Spodoptera frugiperda