Electronic Theses and Dissertation

Coleoptera memainkan peran penting dalam menjaga keseimbangan ekosistem pertanian, namun kompsisinya dapat berubah seiring perubahan fase pertumbuhan tanaman dan faktor ekologi lokal. Penelitian ini bertujuan untuk (1) menganalisis tingkat kesamaan dan dominansi spesies Coleoptera, (2) menguji signifikan antar fase pertumbuhan dan wilayah pengamatan, (3) menganalisis pola hubungan dan variasinya berdasarkan pertumbuhan jagung di Kabupaten Nagan Raya. Penelitian ini menggunakan pendekatan kuantitatif dan jenis penelitian observasi. Metode yang digunakan adalah metode observasi dengan teknik purposive sampling. Pengambilan objek penelitian dengan menggunakan pitfall trap dan hand coleccting. Analisis data mencakup indeks kesamaan Sorensen, indeks dominansi Simpson, analisis ANOVA dua arah, korelasi pairwise, dan PCA untuk mengkaji pola variasi komunitas Coleoptera antar fase pertumbuhan jagung. Analisis statistik dilakukan menggunakan perangkat lunak R Studio. Hasil penelitian menunjukkan bahwa (1) tingkat kesamaan spesies Coleoptera antar lokasi tergolong rendah pada semua fase, sementara indeks dominansi menunjukkan tidak adanya spesies yang mendominasi secara kuat, (2) Terdapat perbedaan nyata dalam tingkat kesamaan dan dominansi spesies Coleoptera berdasarkan fase pertumbuhan jagung dan lokasi pengamatan. (3) Kesamaan spesies antar fase menunjukkan pola hubungan positif yang kuat, terutama antara fase berbunga dan panen. Setiap fase pertumbuhan memberikan kontribusi berbeda terhadap variasi struktur komunitas.

Kata Kunci: Coleoptera, tingkat kesamaan, dominansi, hubungan, variasi.

Coleoptera play an important role in maintaining the balance of agricultural ecosystems, but their composition can change with changes in plant growth phases and local ecological factors. This study aims to (1) analyze the level of similarity and dominance of Coleoptera species, (2) test for significant differences between growth phases and observation areas, (3) identify patterns of relationships and variations based on corn growth in Nagan Raya District. This research used a quantitative approach and observational research type. The method used was observation method with purposive sampling technique. Research objects were collected using pitfall traps and hand coleccting. Data analysis included Sorensen's similarity index, Simpson's dominance index, two-way ANOVA analysis, pairwise correlation, and PCA to examine patterns of Coleoptera community variation between corn growth phases. Statistical analysis was conducted using R Studio software. The results showed that (1) the level of Coleoptera species similarity between locations was low in all phases, while the dominance index showed no species that dominated strongly, (2) There were significant differences in the level of similarity and dominance of Coleoptera species based on corn growth phase and observation location. (3) Species similarity between phases showed a strong positive relationship pattern, especially between flowering and harvesting phases. Each growth phase shows a strong positive relationship, especially between flowering and harvesting phases. Keywords: Coleoptera, similarity, dominance, relationship, variation.