Diversity and Spatial Distribution of Scarabaeidae (Insecta: Coleoptera) in Sarawak.
Beetles of Scarabaeidae have many ecological roles in terrestrial ecosystems. They are important as agricultural pests, biological control agents, pollinators, decomposers, and biological and environmental indicators. Despite their abundance in the ecosystem, there is no comprehensive checklist of s...
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| Format: | Thesis |
| Language: | English English English |
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UNIMAS Publisher
2025
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/49133/ |
| Abstract | Abstract here |
| Summary: | Beetles of Scarabaeidae have many ecological roles in terrestrial ecosystems. They are important as agricultural pests, biological control agents, pollinators, decomposers, and biological and environmental indicators. Despite their abundance in the ecosystem, there is no comprehensive checklist of scarab beetle, and lack of distribution models of the studied taxa to map high biodiversity area using their distribution. Hence, this study aims to document and compare the diversity of scarab beetles and predict their spatial distribution across different localities in Sarawak. Therefore, this study utilised various sampling methods such as handpicking, aerial netting, baited traps, flight intercept traps, and light traps covering 17 localities within Sarawak. As a result, a total of 1,551 beetle individuals were collected representing 126 total species from six subfamilies (Apodiinae, Cetoniinae, Dynastinae, Melolonthinae, Rutelinae, and Scarabaeinae). Among these, Melolonthinae was recorded as the most speciose and abundant subfamily with 49 species (39.99%) and 909 individuals (58.61%), respectively. In terms of individual count, the most abundant species was represented by Apogonia destructor with 315 individuals (20.31%). By localities, Sebangkoi is the most speciose site recorded with 46 beetle species, whereas Samunsam Wildlife Sanctuary was recorded with the most abundant with 311 individuals. Overall, Sabal Agroforestry had the highest biodiversity indices (Simpson 1-D = 0.9451; Shannon = 3.352). Besides, heath forest was recorded as the most diverse forest type for scarab beetles
(Simpson 1-D = 0.9655; Shannon = 3.548). Additionally, the Jaccard similarity index was calculated between localities and forest types, where Gua Temurang and Gua Raya were
found to have the highest index among all localities with 0.381. Meanwhile, limestone forests and mixed dipterocarp forests shared the highest Jaccard similarity index of 0.2609. For spatial distribution of Scarabaeidae in Sarawak, selected genera, namely, Ixorida sp. v (AUC = 85.4%), Chalcosoma spp. (AUC = 85.1%), Apogonia spp. (AUC = 90.6%), Anomala spp. (AUC = 90.1%) and Onthophagus spp. (AUC = 87.0%) were analysed and all models showed similar distribution prediction toward the coastal line of
Sarawak. Of these, Bio 4, Bio 13, Bio 15, Bio 17, and Bio 18 were found as the most contributing environmental variables, representing temperature seasonality, precipitation of
wettest month, precipitation seasonality, precipitation of driest quarter and precipitation of warmest quarter, respectively. In general, these models could be useful especially to the local authorities for future planning of biodiversity conservation and ecosystem’s management.
However, it is recommended that further studies can be rigorously conducted in terrestrial landscapes to provide a more comprehensive database for future conservation efforts. |
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