Life Cycle and Mass Occurrence of Paracolopha morrisoni (Hemiptera: Aphididae) in South Korea

Paracolopha morrisoni (Baker, 1919) (Aphididae: Eriosomatinae) is a gall-forming aphid that alternates between Zelkova serrata (Thunb.) Makino (Ulmaceae) and bamboo hosts in East Asia. Here, we provide field-based documentation of its seasonal biology and host alternation in South Korea, supported by DNA barcoding. Subterranean colonies on the roots of Pseudosasa japonica (Siebold & Zucc. ex Steud.) Makino ex Nakai (Poaceae), together with observations of migratory alates and larviposition, confirmed this bamboo as a secondary host. Phyllostachys heterocycla (Carrière) Matsum. (Poaceae) was identified as a potential secondary host based on settlement and larviposition by migratory alates, although subterranean colony establishment remains unconfirmed. We also documented the predatory mite Anystis baccarum (Linnaeus, 1758) (Anystidae) in association with P. morrisoni and a conspicuous mass occurrence of returning alates in a recreational environment during late autumn. These observations expand current knowledge of the field biology of P. morrisoni and provide ecological information useful for recognizing its seasonal stages and host associations in South Korea.