Palaeoenvironment of the Areas Surrounding the Angkor Thom Moat Inferred from Entomological Analysis

Abstract

Fossil insect remains were extracted for analysis from the moat deposits of Angkor Thom, Cambodia. A total of 84 insect fossils were found. The insect assemblage basically consisted of terrestrial phytophagous insects accompanied by omnivorous and coprophagous surface dwellers. Phytophagous and carnivorous aquatic insects also were present but in significantly smaller numbers. Among the insect fauna were phytophagous species such as Anomala albopilosa Hope and Anomala sp., both of which are known pests to man-made secondary forests and cultivated plants such as upland fields and fruit trees. There was an abundance of aquatic insect species inhabiting paddy environments, including Coelostoma stultum (Walker), Dineutus orientalis Modeer, and Hydrophilidae, regarded to be indicators for rice paddy development. In addition, a well-recognized rice pest, Scotinophara lurida Burmeister, also was among the insects identified. For this reason, it is extremely likely that rice cultivation had existed in the areas surrounding the Angkor Thom moat. Furthermore, coprophagous insects such as Onthophagus sp. and Aphodius sp. also were detected among the fossils, suggestive of pollution of the surrounding environment by human and animal wastes.