Parasitism of Cydia spp. (Lepidoptera : Tortricidae) on Sophora chrysophylla (Fabaceae) along an elevation gradient of dry subalpine forest on Mauna Kea, Hawaii

摘要

The biology and ecological importance of Hawaiian endemic Cydia spp. (Lepidoptera: Tortricidae) are poorly known. Cydia larvae are an important food to palila, an endangered Hawaiian bird that inhabits Sophora woodlands on Mauna Kea, Hawaii. We quantified Cydia larval abundance in seeds of Sophora chrysophylla Salisbury (Fabaceae) and larval mortality caused by parasitism. Four new host plant associations are reported: C. crassicornis [Walsingham], C. falsifalcella [Walsingham], C. obliqua [Walsingham], and C. storeella [Walsingham]. Four parasitoid wasp species were consistently reared from larval Cydia: Calliephialtes grapholithae [Cresson], Diadegma blackburni [Cameron], Pristomerus hawaiiensis Perkins (Hymenoptera: Ichneumonidae), and Euderus metallicus [Ashmead] (Hymenoptera: Eulophidae). The three Ichneumonidae appear to be accidental introductions, while E. metallicus is likely to be native to Hawaii. Parasitism rates by all four wasps combined decreased with elevation from 94% at 1800 m to 20% at 2700 m.