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Phytophagous insect communities in the canopies of three Eucalyptus forest types in south‐eastern Australia
Author(s) -
OHMART C. P.,
STEWART L. G.,
THOMAS J. R.
Publication year - 1983
Publication title -
australian journal of ecology
Language(s) - English
Resource type - Journals
eISSN - 1442-9993
pISSN - 0307-692X
DOI - 10.1111/j.1442-9993.1983.tb01336.x
Subject(s) - biology , eucalyptus , canopy , crown (dentistry) , curculionidae , tree canopy , insect , hectare , abundance (ecology) , ecology , medicine , dentistry , agriculture
Intensive sampling of tree canopies for phytophagous insects was carried out in three contrasting eucalypt forest types comprised of species widely distributed in sub‐alpine forests in Victoria and New South Wales (Eucalyptus delegatensis, E. dives, and E. pauciflora). The number of phytophagous insects present in the canopies of these forest types was low, with a seasonal average of 20 individuals per kg of foliage (dry weight). Numbers were much lower than expected from past literature reporting‘chronically high’levels of defoliation in eucalypt forests.Microlepidoptera, Geometridae, Chrysomelidae, and Curculionidae were the major leaf‐chewing groups recorded. Most sap‐feeders were either leafhoppers (Cercopidae and Cicadellidae) or in the superfamily Fulgoroidea. Psyllidae and gall‐making species were rare. Leafhoppers made up a very large portion of the phytophagous insect communities in each forest type, particularly in the E. dives forest. Microlepidoptera was the most commonly encountered defoliator group in all three forest types making up 33‐44% of the total count. Non‐phytophagous arthropods accounted for 44‐48% of all individuals encountered. The density of insect defoliators was greater in the lower crown than upper crown.The E. dives canopy supported many more phytophagous insects per unit weight of foliage, as well as more per hectare, than the other two forest types. The greatest number of phytophagous species was also encountered in E. dives canopy. The E. delegatensis canopy supported the lowest number of phytophagous insects per unit weight of foliage as Well as numbers per hectare.Abundance of insect defoliators in the eucalypt forest types in this study was similar to published figures of insect defoliators in northern temperate forests.