Prior to European settlement of New Zealand, the shallow river was thickly lined with matai, rimu, and totara trees that prevented serious flooding to the swampy lands alongside the river.
The larvae feed on a wide range of trees and shrubs, including Dacrydium cupressinum, Prumnopitys taxifolia, Dacrycarpus dacrydioides, Libocedrus bidwillii, Cupressus macrocarpa, Leptospermum scoparium, Kunzea ericoides, Ozothamnus leptophyllus, Abies, Picea, Pinus and Thuja species.