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: DEVELOPMENT OF A NEW COLONY OF Tetragonula laeviceps USING THE GRAFTING METHOD
Abstrak: Meliponikultur adalah istilah yang digunakan untuk membudidayakan lebah tanpa sengat seperti Tetragonula laeviceps. Tetragonula laeviceps adalah jenis stingless bee yang memiliki potensi besar dalam menghasilkan propolis dan madu bernilai tinggi. Namun, teknik propagasi koloni T. laeviceps masih kurang dikaji meskipun jumlah peternak stingless bee di Indonesia meningkat. Metode cangkok merupakan cara budidaya koloni stingless bee yang alami. Penelitian ini bertujuan mengamati perkembangan koloni baru T. laeviceps melalui teknik pencangkokan. Metode ini dilakukan dengan cara menghubungkan sarang sumber asal ke sarang buatan menggunakan selang transparan. Sarang buatan tersebut merupakan sarang baru yang wadahnya terbuat dari akrilik, bambu, kayu, dan plastik, masing-masing tiga ulangan. Pengamatan dilakukan dalam dua kali seminggu selama lima bulan dengan mengukur berat sarang baru dan lama. Parameter lingkungan yang diukur dalam setiap pengamatan terdiri atas suhu dan kelembapan. Persentase okupasi sarang buatan paling tinggi hingga terendah yaitu bambu, kayu, akrilik, dan plastik. Namun, persentase okupasi pada sarang buatan dengan sarang sumber tidak ditemukan korelasi yang signifikan. Metode cangkok pada Tetragonula laeviceps membutuhkan waktu yang lebih lama untuk meliponikultur baik menggunakan bahan kayu, plastik, akrilik ataupun bambu., Meliponiculture is the term used for cultivating stingless bees such as Tetragonula laeviceps. Tetragonula laeviceps is a type of stingless bee that has great potential in producing high-value propolis and honey. Unfortunately, the propagation technique for T. laeviceps colonies is still poorly studied although the stingless bee breeders in Indonesia increase. The grafting method is the natural way of cultivating stingless bee colonies. This study aims to observe the development of new colonies of T. laeviceps using grafting techniques. This method is carried out by connecting the original source nest to the artificial nest using a transparent hose. The artificial nest is a new nest whose container is made of acrylic, bamboo, wood and plastic, three repetitions of each. Observations were made twice a week iii for five months by measuring the weight of new and old nests. The environmental parameters measured in each observation consist of temperature and humidity. The highest to lowest percentage of artificial nest occupation was bamboo, wood, acrylic and plastic. However, no significant correlation was found between the percentage of occupancy in artificial nests and source nests. The grafting method on T. laeviceps requires longer time for liponiculture using either wood, plastic, acrylic or bamboo.
Keyword: Meliponiculture, Stingless bee, Tetragonula laeviceps

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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