Judul: Trap-Nest Effectivity in Trapping Stingless Bee Colony
Abstrak: Trap-nest is an environmentally friendly method of obtaining wild stingless bee colonies, because the process would be done without damaging the nest structure and does not require colony relocation to a new nest box. In spite of its advantages, this technique has not yet been systematically studied well. The study aims to verify the occupation rate, find the preferred material for the stingless bee colonies, and species diversity that can be obtained by the trap-nest. In evaluating those aspects, 126 units of trap-nest from two different materials (plastic bottle and bamboo) containing stingless bee propolis extract as an attractant were deployed. Over a period of 6 months, 4 swarms from the species Tetragonula laeviceps were attracted to the trap-nest and established a colony inside. Not only that, as many as 33 ant colonies were also caught nesting within the trap-nest as competitors. The trap-nest technique has the potential as a standard method in obtaining stingless bee colonies for meliponiculture and conservation., Perangkap sarang merupakan salah satu metode ramah lingkungan dalam memperoleh koloni kelulut liar, karena prosesnya dilakukan tanpa merusak struktur sarang dan tanpa harus memindahkan koloni ke kotak sarang buatan. Meski begitu, teknik ini masih belum banyak dipelajari secara sistematis. Penelitian ini bertujuan mendapatkan persentase okupansi perangkap sarang, mengetahui preferensi kelulut dalam memilih material perangkap sarang, dan mengidentifikasi macam spesies yang dapat diperoleh dari metode perangkap sarang. Dalam meninjau hal tersebut, digunakan 126 unit perangkap dengan dua material berbeda (botol plastik dan bambu) yang telah diberi ekstrak propolis kelulut sebagai atraktan. Dalam waktu 6 bulan, didapati 4 koloni dari spesies Tetragonula laeviceps tertarik pada perangkap sarang material bambu dan membuat sarang didalamnya. Selain itu, sebanyak 33 koloni semut juga didapati menetap dalam perangkap sebagai kompetitor kelulut. Teknik perangkap sarang memiliki potensi sebagai metode utama perolehan koloni kelulut dalam upaya meliponikultur maupun konservasi.
Keyword: conservation, meliponiculture, trap nest, stingless bee

Judul: The Species Diversity, Nesting Biology, and Preference of Foraged Plants Based on Pollen Load Analysis of Stingless  Bees (Hymenoptera: Apidae) in Aceh Province
Abstrak: Sebagai bagian integral dari serangga berguna dalam penyerbukan, studi tentang keanekaragaman dan biologi persarangan lebah tanpa sengat sangat diperlukan. Informasi mengenai lebah tanpa sengat di Provinsi Aceh belum tersedia sampai saat ini. Studi ini bertujuan untuk menganalisis keanekaragaman spesies dan biologi persarangan lebah tanpa sengat Indo-Malaya di Provinsi Aceh. Penelitian ini juga bertujuan untuk mendokumentasikan tanaman pakan lebah dan muatan polen melalui analisis polen pada korbikula tubuh. Melalui survei eksploratif, data dikumpulkan dari dua lokasi observasi, yaitu Kabupaten Aceh Besar dan Bener Meriah di Provinsi Aceh antara bulan Juli dan Agustus 2023. Hasil penelitian menunjukkan bahwa sepuluh spesies lebah tanpa sengat telah tercatat. Panjang tubuh lebah tanpa sengat berkisar antara 4,6 hingga 11,7 mm dan panjang sayap depan antara 3 hingga 8,8 mm. Lokasi bersarang lebah tanpa sengat ditemukan pada material alami dan material yang terkait dengan pemukiman. Pintu masuk sarang bervariasi dengan panjang 1,75-13,54 cm, diameter horizontal 0,65-7,57 cm, diameter vertikal 0,45-7,46 cm, bentuk rongga berupa lingkaran dan tidak beraturan dengan tekstur lembut dengan resin dan pori-pori. Warna pintu masuk dominan dim gray. Sarang ini terletak 1-300 m dari sumber air dengan ketinggian 0-600 cm di atas permukaan tanah. Variasi pada corong pintu masuk sarang terkait dengan biologi dan adaptabilitas koloni terhadap lingkungan. Selama periode penelitian di Provinsi Aceh teridentifikasi polen dari 163 jenis tumbuhan pakan. Selain itu, 4 polen teridentifikasi hingga tingkat famili, dan 10 polen tumbuhan tidak dapat teridentifikasi. Geniotrigona thoracica dan Tetragonula fuscobalteata dari seluruh lebah yang dianalisis dalam penelitian ini memiliki kemampuan mengangkut polen terbanyak (37.650 butir polen) dan terendah (2.350 butir polen). Kemampuan mengangkut polen tertinggi hingga terendah yaitu Geniotrigona thoracica (37. 650 butir), Heterotrigona itama (28.050 butir), Tetragonilla collina (27.450 butir), Lepidotrigona terminata (23.800 butir), Tetragonula minangkabau (17.950 butir), Lepidotrigona ventralis (17.500 butir), Tetragonula laeviceps (10.150 butir), Sundatrigona moorei (4.150 butir), Tetragonula geissleri (3.100 butir), dan Tetragonula fuscobalteata (2.350 butir)., As an integral part of beneficial insects in pollination, studying the diversity and nesting biology of stingless bees is essential. Information on stingless bees in Aceh Province has not been available until now. This study aims to analyze the species diversity and nesting biology of Indo-Malayan stingless bees in Aceh Province. The study also aims to document preference of foraged plants in stingless bees. Through an exploratory survey, data were collected from two observation sites, Aceh Besar and Bener Meriah Regencies in Aceh Province, between July and August 2023. The results show that ten species of stingless bees have been recorded. The body length of stingless bees ranges from 4.6 to 11.7 mm and the forewing length ranges from 3 to 8.8 mm. Nesting locations were found in both natural materials and materials associated with human settlements. The entrance tube lengths varied from 1.75 to 13.54 cm, with horizontal diameters ranging from 0.65 to 7.57 cm and vertical diameters ranging from 0.45 to 7.46 cm. The entrance cavity shapes were either circular or irregular, with a soft texture featuring resin and pores. The entrance color was predominantly dim gray. The nests were located 1-300 meters from water sources and at heights of 0-600 cm above
Keyword: adaptabilitas lingkungan, distribusi geologi, ekoregion Indo-Malaya, muatan polen

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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