Field evidence of Plesiochrysa ramburi (Neuroptera: Chrysopidae) establishment and predation on invasive mealybugs in the Sakishima Islands, Japan

Spreading invasive pest insects cause substantial agricultural damage worldwide. Their natural enemies can also expand their distributions, thus presenting potential opportunities for biological control. The green lacewing Plesiochrysa ramburi (Schneider), widely distributed from Southeast Asia to Australia, Polynesia, and Micronesia, has potential as a natural enemy for agricultural pest control owing to its predation on economically important pest mealybugs. Only a few specimens have been recorded in Japan in recent years, and the species’ ecological characteristics in the region remain poorly understood. Here, we recorded multiple adults and immatures—eggs, larvae, and pupae—of P. ramburi associated with invasive pest mealybugs in the Sakishima Islands, Japan. Collection of the lacewings from multiple sites on Ishigaki Island and their observation on Miyako Island, over 100 km away, confirms widespread establishment in the region. Immature stages were closely associated with colonies of three invasive mealybug species, Paracoccus marginatus, Phenacoccus solenopsis, and Maconellicoccus hirsutus. Larvae of P. ramburi, covered with wax secretions from their prey, were observed preying on the mealybugs. We discuss the potential for P. ramburi to continue expanding its distribution and its potential as a natural enemy for pest control in Japan.