Abstract: Both larvae and adults of Parena cavipennis can predate on the larvae of the fall webworm (Hyphantria cunea). Predation of the fall webworm larvae by P. cavipennis was investigated through measuring the predation amount of 3^rd instar P. cavipennis larvae on the 3^rd, 4^th, and 5^th instar fall webworm larvae, as well as the functional response and searching efficiency of P. cavipennis adult to these larvae under laboratory conditions. The results showed that: 1) The daily predation quantity of the 3^rd instar P. cavipennis larvae decreased with the development of fall webworm larvae. The daily predation weight increased progressively across larval instars of the fall webworm. Specifically, the daily predation quantity was 2.78, 1.33, and 1.11 on the 3^rd, 4^th, and the 5^th instar fall webworm larvae, respectively, and the daily predation weight was 0.21 g, 0.26 g, and 0.56 g, respectively. 2) The functional response of P. cavipennis adult to the 3^rd, 4^th, and 5^th instar fall webworm larvae followed the Holling II model. The instantaneous attack rates were 1.4638, 0.5879, and 1.0283, respectively, and the handling time was 0.1572 d, 0.1894 d, and 0.4443 d, respectively. The maximum daily predation quantity was 6.3594, 5.2800, and 2.2508, respectively. As density of the fall webworm larvae per unit space increased, the searching efficiency of P. cavipennis adult for the 3^rd, 4^th, and 5^th instar larvae decreased. These findings suggest that P. cavipennis has potential for controlling fall webworm larvae. Further studies are needed to explore the predatory efficiency of P. cavipennis under different conditions, providing new approaches and methods for the management of fall webworm.

Key words: Parena cavipennis, Hyphantria cunea, predatory natural enemies, predatory effect, Holling II functional response model