Foliage insect diversity in dry eucalypt forests in eastern Tasmania

Abstract

Species numbers and composition of the insect fauna occurring on trees and shrubs were studied in dry eucalypt forests in eastern Tasmania over nine years. In all, 1164 named and putative species representing 17 orders and 157 families were collected. The bulk of the species belonged to the orders Coleoptera (28%), Hymenoptera (25%), Hemiptera (18%), Lepidoptera (14%) and Diptera (10%). Of the species collected, 388 -- about one-third -- were identified at least to genus or species level. These included 21 named species not previously listed in the Tasmanian insect fauna and 90 undescribed species. A list of 22 host plants for 171 insect species was compiled from records of 132 insect species observed feeding during the study and from previous records ofinsect/host plant associations for 39 insect species found on the study plots. Most insects were feeding on eucalypts (127 insect species) and acacias (38 species). The most widely distributed and commonly collected species were several well-known pests of eucalypts: Gonipterus scutellatus (Coleoptera: Curculionidae), Uraba lugens (Lepidoptera: N octuidae), Amorbus obscuricornis (Hemiptera: Coreidae), Chaetophyes compacta (Hemiptera: Machaerotidae) and Eriococcus coriaceous(Hemiptera: Eriococcidae). Host plants supporting the richest insect fauna were Eucalyptus amygdalina (74 species), E. obliqua (64), E. viminalis (46), Acacia dealbata (35), E. dalrympleana (33), E. sieberi (31), E. delegatensis (30), E. pulchella (24) and E. globulus (19). The broad-striped ghost moth, Fraus latistria Walker (Lepidoptera: Hepialidae), was collected during the study. This species is classified as 'rare' on the list of Tasmania's threatened fauna and the collection established a new locality record.