Dung beetle (Scarabaeinae)

Mohamed bin Zayed Species project number 232532176

Diversity of Dung Beetles (Coleoptera: Scarabaeinae) in the Cardamom Mountains, Southwest Cambodia

Dung beetles are ubiquitously found in various habitats including forest, grassland, agricultural farmland, and also in the desert etc. Member of Dung beetles in subfamily Scarabaeinae provide many important services in many different ecosystems such as nutrient recycling, biological pest control, and secondary seed dispersal (Latha & Sabu 2018), especially in tropical savannas and forests (Hanski & Cambefort, 1991). Dung beetles mailnly feed on dungs of different animals for their whole lifecycle (Hanboonsong et al., 1999). Despite ecological important, the fundamental studies on taxonomy and ecology of dung beetles in Cambodia are less attention. To date, only 63 species of dung beetles have been recorded from Cambodia, which this number is far behind compared to neighbor countries (Han et al., 2020). The Cardamom Mountain maintain diverse suitable habitats which it believed to support a high diversity of invertebrate. However, there is no documents or scientific study report about diversity of the dung beetles in this unique area yet. Therefore, this project will provide a baseline data records and information of dung beetle diversity to support further research and conservation in Cambodia.

Overall objective of the proposed project is to compile a species list of dung beetles in the Cardamom Mountains, southwest Cambodia in order to create a documentary for future biodiversity researches and monitoring in the area. The specific project objectives of this study are to: 1) investigate diversity (species richness, species abundance, and species diversity index) of dung beetles in the seasonal variation (dry and rainy seasons) in the Cardamom Mountains, 2) seasonal comparation of the dung beetle diversity at Cardamom Mountains, dry and rainy seasons 3) improve understanding of the species composition in the targeted area, and 4) assess the conservation needs for the dung beetles in the Cardamom Mountains for conservation purpose.

This research involved the collection of dung beetles utilizing two distinct types of baited pitfall traps: human excrement-baited (HE-baited) and raw fish-baited (RF-baited). To lure the beetles, we employed plastic cups with an open diameter of 8.4 cm and a height of 12.2 cm, which were embedded into the ground so that their openings were flush with the surface. Each trap contained 10 grams of HE-baited or three pieces of RF-baited (approximately 30 grams), as both substances are known to attract a diverse array of dung beetle species and individuals. A total of twenty traps were set up, with one set of ten featuring HE-baited suspended above the cups, while the other set had RF-baited placed directly inside. The beetles were collected from 20 different sites located within the semi-evergreen mixed bamboo forests at SMW. These sites were systematically arranged along a 100-meter transect with 10-meter intervals between each location. To ensure thorough collection, the traps were inspected three times daily, at 7:00 AM, 11:00 AM, and 4:00 PM. In addition to capturing dung beetles using pitfall traps, we also captured dung beetles by searching in guar dungs. All captured dung beetles were then preserved in tubes containing 70% ethanol and labelled appropriately for subsequent identification in the laboratory.