Judul: Inventarisasi Serangga pada Buah Fikus, Ficus spp. (Moraceae) di Bogor
Abstrak: Pohon fikus (Ficus spp.) merupakan spesies kunci (keystone) yang memiliki peran penting bagi ekosistem hutan. Buah yang dihasilkan sepanjang tahun dapat bermanfaat sebagai pakan untuk satwa liar. Selain itu pohon fikus merupakan spesies yang biasa digunakan dalam kegiatan revegetasi karena bersifat pionir. Ciri khas yang dimiliki pohon fikus yaitu bunga terdapat dalam struktur yang menyerupai buah disebut sikonia (syconium) dan penyerbukan terjadi di dalam struktur yang menyerupai buah tersebut. Ciri khas lainnya yaitu satu spesies pohon fikus hanya bisa diserbuki oleh satu spesies serangga saja (penyerbukan bersifat spesifik). Begitu pula sebaliknya, satu spesies serangga penyerbuk hanya bisa menyerbuki satu spesies pohon fikus saja. Serangga yang bisa hidup pada buah fikus tidak hanya penyerbuk, terdapat serangga non-penyerbuk yang juga bisa hidup pada buah fikus. Penelitian ini bertujuan untuk memelajari jenis serangga yang berasosiasi dengan buah Ficus benjamina, Ficus hispida dan Ficus racemosa yang terdapat di IPB University dan Kebun Raya Bogor. Koleksi buah fikus dilakukan dari 3-4 pohon fikus per spesies. Sejumlah 10-30 buah per pohon dikoleksi untuk diamati jenis-jenis serangga yang berkembang di dalamnya. Semua serangga yang ditemukan berasosiasi dengan buah fikus adalah dari ordo Hymenoptera (famili Agaonidae). Serangga penyerbuk yang ditemukan yaitu Ceratosolen solmsi sebagai penyerbuk pada Ficus hispida, Ceratosolen fusciceps sebagai penyerbuk pada Ficus racemosa dan Eupristina sp. sebagai penyerbuk pada Ficus benjamina. Serangga non-penyerbuk yang ditemukan yaitu Phylotrypesis sp. (Hymenoptera: Pteromalidae) pada Ficus hispida, Apocryptophagus sp. (Hymenoptera: Agaonidae) pada Ficus racemosa dan Sycoscapter sp. pada Ficus benjamina (Hymenoptera: Pteromalidae). Dari 175 buah yang dikoleksi, 70% tidak ditemukan serangga di dalamnya, Ficus tree (Ficus spp.) is a keystone species that has an important role in forest ecosystems. The fruit produced throughout the year can be useful as feed for wildlife. In addition, ficus tree is a species commonly used in revegetation activities because it is a pioneer. The characteristic of ficus trees is that the flowers are in a fruit-like structure called a syconium and pollination occurs in a fruit-like structure. Another characteristic is that one species of ficus tree can only be pollinated by one insect species (pollination is specific). The pollinators are species specific, where one species of pollinating insect can only pollinate one species of ficus tree. Insects that can be found associated with the syconium are not only pollinators, instead there are non-pollinating insects that can also live on ficus fruit. This research aims to study the interaction of insects associated with the fruit of Ficus benjamina, Ficus hispida and Ficus racemosa found at IPB University and Bogor Botanical Gardens. Ficus fruit collection was carried out from 3-4 ficus trees per species. A total of 10-30 fruits per tree were collected to observe the types of insects that developed in them. All insects found in association with ficus fruit are from the order Hymenoptera (family Agaonidae). The pollinators found were Ceratosolen solmsi as pollinator in Ficus hispida, Ceratosolen fusciceps as pollinator in Ficus racemosa and Eupristina sp. as a pollinator in Ficus benjamina. The non-pollinating insects found were Phylotrypesis sp. (Hymenoptera: Pteromalidae) in Ficus hispida, Apocryptophagus sp. (Hymenoptera: Agaonidae) in Ficus racemosa and Sycoscapter sp. in
Keyword: coevolution, Ficus wasp, pollinator

Judul: Diversity of Species and Impact of Non-collection Ficus (Moraceae) in Bogor Botanic Gardens
Abstrak: Ficus sebagian besar ditemukan di wilayah Indo-Malaya. Di Indonesia, persebaran Ficus hampir merata di tiap pulaunya. Kebun Raya Bogor sebagai kawasan konservasi eksitu memiliki banyak koleksi Ficus, kehadiran hemiepifit Ficus non koleksi dapat menimbulkan dampak yang serius bagi Kebun Raya Bogor. Penelitian ini bertujuan untuk menginventarisasi keragaman jenis Ficus serta menapis Ficus non koleksi yang dapat direkomendasikan sebagai koleksi spontan di Kebun Raya Bogor. Data yang digunakan berupa data pengamatan langsung di lapangan menggunakan metode jelajah, dilanjutkan dengan identifikasi tumbuhan, dan analisis data. Hasil penelitian menunjukkan bahwa, sebanyak 45 jenis Ficus dijumpai di Kebun Raya Bogor yang terdiri dari 36 jenis Ficus koleksi dan 23 jenis Ficus non koleksi. Habitus yang teramati sebanyak 63% berhabitus pohon, 18% hemiepifit, 7% semak, 7% pemanjat, dan 5% perdu. Ficus non koleksi di Kebun Raya Bogor dapat menempel, merusak, bahkan mematikan substrat maupun pohon inang yang ditumpanginya. Walaupun demikian, Ficus non koleksi juga memiliki dampak positif yaitu dapat menambah keragaman jenis Ficus yang terdapat di Kebun Raya Bogor. Jenis Ficus non koleksi yang berpotensi dijadikan sebagai tanaman koleksi spontan direkomendasikan sebanyak 17 jenis., Ficus is mainly found in the Indo-Malayan region. In Indonesia, Ficus is almost evenly distributed throughout the islands. Bogor Botanic Gardens as an ex-situ conservation area has a large Ficus collection. However, non-collection hemiepiphytic Ficus can have severe impacts on Bogor Botanic Gardens. This research aims to inventory the diversity of Ficus and sort non-collection Ficus that can be recommended as spontaneous collection in Bogor Botanic Gardens. The data used consisted of direct field observations using the exploration method, followed by plant identification, and data analysis. The results showed that a total of 45 species of Ficus were found in Bogor Botanic Gardens, consisting of 36 species of Ficus collection, and 23 species of non-collection Ficus. The observed habitus included 63% trees, 18% hemiepiphytes, 7% shrubs, 7% climbers, and 5% bushes. Non-collection Ficus in Bogor Botanic Gardens can adhere to, damage, or even kill the substrates or host trees they inhabit. Nevertheless, non-collection of Ficus also has a positive impact by increasing the diversity of Ficus in Bogor Botanic Gardens. Seventeen non-collection Ficus species are recommended as potential spontaneous collection plants.
Keyword: habitus, ex-situ coservation, hemiepiphyte, species diversity, spontaneous collection

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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