关键词: 大灰优蚜蝇, 扶桑绵粉蚧, 生物防治, 捕食功能反应, 干扰反应

Abstract: 【Aim】This study aims to ascertain the predation capability and biological control potential of the syrphid, Eupeodes corollae against the nymphs and female adults of the mealybug, Phenacoccus solenopsis.【Methods】The predation capabilities of the 1st-3rd instar larvae of E. corollae on the 1st-3rd instar nymphs and female adults of P. solenopsis at different densities were tested under laboratory conditions. The Holling and Hassell models were used to fit the predatory functional response and intraspecific interference response of E. corollae to P. solenopsis.【Results】Preying on P. solenopsis, E. corollae larvae exhibited searching, probing, attacking and feeding behaviors. The predation rates of the 1st-3rd instar larvae of E. corollae on nymphs and female adults of P. solenopsis increased with the developmental stages of E. corollae increasing. Moreover, the predation rates of the 1st-3rd instar larvae of E. corollae on P. solenopsis nymphs were higher than those on female adults of P. solenopsis. In a certain range of prey densities, the predation of the 1st-3rd instar larvae of E. corollae on the 1st and 2nd instar nymphs of P. solenopsis fitted the Holling type Ⅲ functional response model, the instantaneous attacking rates were positively correlated with the prey densities, and the prey handling time decreased and the theoretically maximum daily predation amount of prey increased as the developmental stages of E. corollae increased. The predation of the 1st-3rd instar larvae of E. corollae on the 3rd instar nymphs and female adults of P. solenopsis fitted the Holling type Ⅱ functional response model, the daily predation amount was positively correlated with the prey density, and the instantaneous attacking rate of E. corollae against prey increased, the theoretically maximum daily predation amount of prey and predation capability also increased while the prey handling time decreased with the increase of the developmental stages of E. corollae. The predation rates of the 1st-3rd instar larvae of E. corollae to female adults of P. solenopsis were negatively correlated with the predator densities, indicating an increase in intraspecific interference with the increase of predator density.【Conclusion】Taken together, these results indicate that E. corollae larvae have good control potential on the nymphs and female adults of P. solenopsis. The current study provides a theoretical basis for evaluating the biological control potential of E. corollae larvae against P. solenopsis.

Key words: Eupeodes corollae; Phenacoccus solenopsis, biological control, predatory functional response, interference response