Coconut is a major cash crop of Papua New Guinea (PNG) and Scapanes australis rhinoceros beetles are its major pests. Currently there is no effective control method Research is focused at developing an integrated pest management scheme for which a knowledge of the biology and ecology of the pest is required. This paper reports investigations on the determination of the larval development sites of the beetle, which play a key role in the search for natural enemies and IPM strategy. Intensive field prospecting on the Gazelle Peninsula in East New Britain Province found Scapanes australis subspecies grossepunctatus Sternberg extensively on the rotting stumps of Gliricidia sepium Jacquin which is commonly used as a shade tree for cocoa, whereas on Karkar Island Scapanes australis subspecies australis Boisduval was found extensively in well rotted coconut stumps (Coco nucifera L), and in the organic leafmounds made by nesting wildfowl (Megapodus freycinet) associated with the tree roots of Artocarpus altilis (breadfruit).