Stem-galling moths provide cetoniine beetles with feeding sites via sap exudation of invasive alien plants

摘要

The alien moth Epiblema sugii (Lepidoptera: Tortricidae) induces stem galls on an invasive alien weed, Ambrosia trifida. During summer, along riverbanks in central Japan, the native insects Protaetia brevitarsis, P. orientalis submarumorea (Coleoptera: Scarabaeidae: Cetoniinae), and Camponotus vitiosus (Hymenoptera: Formicidae) feed on the sap exuded from the galls. The cetoniine beetles are highly aggregated among the galls and make wounds on the galls to facilitate sap exudation. Feeding on gall sap may be beneficial to the beetles due to the efficient intake of water and sugar, and the beetles' inflicting wounds and feeding on the sap seem to have little effect on the gallers. This is a unique finding, where alien plant-galler interaction provides a feeding site for native insects.