Consequences of gall tissues as a food resource for a tortricid moth attacking cecidomyiid galls

摘要

Seven species of parasitoids and two species of moths emerged from bud galls induced by two species of gall midges (Asteralobia soyogo (Kikuti) and A, sasakii (Monzen)) (Diptera: Cecidomyiidae) on four species of trees of the genus Ilex (I pedunculosaMiq., I. crenata Thunb., I. chinensis Sims, and I. intégra Thunb.) (Aquifoliaceae). Larvae of the moth Rhopobota ustomaculana (Curtis) (Lepidoptera: Tortricidae) bored into bud galls induced by A. soyogo and A. sasakii on I. pedunculosa and I. crenata,respectively. Rhopobota ustomaculana larvae fed on leaves as well as gall tissues of I. pedunculosa, suggesting that R. ustomaculana is a facultative cecidophage. To clarify consequences of gall tissues as a food resource for cecidophagous moths, we compared the chemical properties of galls with those of normal plant tissues (leaves) of I. pedunculosa. Bud galls of I. pedunculosa had higher water content and lower nitrogen, carbon, and polyphenol (a chemical associated with plant insect defenses) contents than leaves. Therefore, bud galls may be a richer food resource for R. ustomaculana larvae because of the higher water content and lower carbon and polyphenol contents, although they are a poorer resource in terms of nitrogen content.