Judul: Soybean canopy dwelling predatory arthropods with the emphasis on Paederus fuscipes (Curt.) (Coleoptera: Staphylinidae)
Abstrak: Penelitian dilaksanakan pada lahan kedelai di Kecamatan Ciranjang, Kabupaten Cianjur, Jawa Barat pada musim kemarau 1997 dan 1998, dan bertujuan untuk menganalisis kompleks predator penghuni tajuk serta peranannya di pertanaman kedelai, memahami perkembangan populasi dan tingkat pemangsaan kumbang Paederus fuscipes (Curt.) (Col.: Staphylinidae), mengkaji pengaruh pemberian mulsa jerami terhadap kelimpahan populasi P. fuscipes, serta mengukur preferensi dan tanggap fungsional P. fuscipes. Hasil penelitian menunjukkan bahwa tajuk kedelai dihuni oleh lebih dari 25 spesies artropoda predator. Predator yang paling dominan adalah kumbang P. fuscipes (Curt.), cengkerik Anaxipha longipennis (Serville) dan laba-laba Pardosa pseudoannulata (Boes. & Str.) dan Atypena adelinae (Barr. & Lit.). Besarnya tekanan pemangsaan oleh predator penghuni tajuk dipengaruhi oleh kelimpahan predator dan fase pertumbuhan tanaman Tekanan pemangsaan terhadap telur mencapai 50% dari total 60 telur, dan terhadap larva mencapai 58% dari total 60 ekor larva yang diumpankan. Fase perkembangan tanaman dan kelimpahan predator mempengaruhi besarnya tekanan pemangsaan. Dengan kerapatan predator 1,47 ekor per rumpun, tekanan pemangsaan terhadap telur pada fase V4 mencapai 48% dari total 60 telur, sedangkan terhadap larva mencapai 67% dari total 60 ekor larva yang diumpankan. Tekanan pemangsaan lebih tinggi pada fase ~ (60% untuk telur, dan 68% untuk larva) yang disebabkan oleh meningkatnya kerapatan predator yang mencapai sekitar 3 ekor per rumpun., Studies were conducted on soybean fields in the sub district of Ciranjang, Cianjur, West Java during the two growing soybean seasons of 1997 and 1998, with the objectives: to analyze the soybean canopy dwelling predatory arthropods and its roles, to analyze the population development and predation rate of Paederus fuscipes (Curt.) (Col.: Staphylinidae), to assess the effect of mulching of paddy straw on population abundance of P. fuscipes, and to determine the prey preference and functional response of P. fuscipes. Results of the studies showed that soybean canopy was inhabited by more than 25 species of predatory arthropods. The most abundant predators were P. fuscipes beetles, cricket Anaxipha longipennis (Serville) and spiders Pardosa pseudoannulata (Boes. Str. )and Atypena adelinae (Barr. & Lit.). The predation pressure varied with predator abundance and soybean growth stage. The predation pressure on eggs was 50% and on larvae 58%. During the growth stage V4, with a predator density of 1,47/hill, the predation pressure was 48% on eggs and 67% on larvae. During growth stage RJ, with a predator density of 3,39/hill, the predation pressure on eggs was 60% and on larvae 68%. P. fuscipes was present throughout the soybean growing stage, with the peak of population (1,5-2 predator/hill) occurred on 6-7 weeks after planting. Each individual beetle consumed 12-14 eggs or 12 instar-1 larvae of Helicoverpa armigera Hbn. (Lep.: Noctuidae) per day. P. fuscipes showed an adaptive searching behavior for the prey. About 32% of H. armigera eggs placed on the upper surface of the leaves were consumed, compared to 19% on the lower surface. Similarly, 53% and 41% of Etiella zinckenella Tr. (Lep. Pyralidae) eggs placed respectively on shoots and pods were consumed, whereas only 6% on eggs placed on leaves.
Keyword: Paederus fuscipes, Predatory

Judul: Ground Surface Dwelling Predatory Arthropods In Soybean Fields: Abundance, Predation Pressure, And Effects Of Cultural Practices
Abstrak: Penelitian dilakukan pada pertanaman kedelai di Kecamatan Ciranjang, Kabupaten Cianjur pada MT 1997 dan 1998, dan di Kecamatan Lemahabang, Kabupaten Karawang pada MT 2000. Penelitian bertujuan untuk menentukan komposisi dan kelimpahan artropoda predator penghuni permukaan tanah dan tekanan pemangsaannya, dan mengkaji pengaruh beberapa praktek budidaya tanaman seperti mulsa jerami dan aplikasi insektisida dan herbisida. Kelimpahan predator diamati menggunakan lubang perangkap, dan tekanan pemangsaan dievaluasi menggunakan larva dan pupa Spodoptera litura (F.) sebagai mangsa umpan. Hasil penelitian menunjukkan bahwa pada permukaan tanah di pertanaman kedelai ditemukan lebih dari 15 jenis artropoda predator. Dua jenis yang paling dominan di Cianjur adalah laba-laba serigala Pardosa pseudoannulata (Boes. & Str.) (Araneae: Lycosidae) dan kumbang tanah Pheropsophus occipitalis (MacLeay) (Coleoptera: Carabidae), sedangkan di Karawang hanya jenis yang disebut pertama yang dominan. Demikian juga tekanan pemangsaan di Cianjur sekitar 9 kali lipat lebih tinggi daripada di Karawang. Perbedaan dominasi dan tekanan pemangsaan ini diduga berhubungan dengan perbedaan struktur lansekap dan intensitas penggunaan insektisida di kedua tempat tersebut. Kelimpahan artropoda predator penghuni permukaan tanah di Cianjur pada MT 1997 lebih rendah dibandingkan MT 1998, demikianjuga halnya dengan. detritivor seperti colembolan dan tungau., Cianjur during the two soybean growing seasons of 1997 and 1998, and in the sub district of Lemahabang, Karawang during 2000. The objectives were to determine the composition and abundance of ground surface dwelling predatory arthropods and their predation pressure, and to evaluate the effects of some cultural practices, i.e. straw mulching, and insecticide and herbicide applications. Ground surface dwelling predatory arthropods were monitored using pitfall traps, and their predation pressure was evaluated using larvae and pupae of Spodoptera litura (F.) as baits. Our research revealed more than 15 species of ground-dwelling predators. The most dominant predators in Cianjur were wolf spider Pardosa pseudoannulata (Boes. & Str.) (Araneae: Lycosidae) and ground beetle Pheropsophus occipitalis (MacLeay) (Coleoptera: Carabidae), whereas in Karawang only the first mentioned species. Predation pressure in Cianjur was 9 times higher than those in Karawang. The differences in species dominance and predation pressure were thought to be related to differences in landscape stuctures and intensity of pesticide uses between the two locations. Abundance of ground-dwelling predators in Cianjur during 1997 growing season was much lower compared to those during 1998, and the same with the detritivores such as collembolans and mites. Predation pressure on lepidopteran larvae placed on soil surface reached 18 individuals per 2 hours which was mostly caused by ground beetles, whereas on pupae 10 individuals per 2 hours caused by shrew. Predation pressure on larvae at distance of 1 m from field bunds were 5 times higher than those placed at 5 m. Predation occurred mostly during the night. Some of the predators climbed the soybean canopy to prey the larvae. Predation pressure decreased with the increasing size of canopy. Incorporation of straw mulch onto soil surface inreased abundance of wolf spiders, dwarf spiders, and ants. The increase of predator population generally occurred several days following mulching. Conversely, burning of straw caused deleterious effects on predators. Immediatelly after burning, abundance of wolf and dwarf spiders, ants, and rove beetles decreased 66 up
Keyword: Arthropods, Soybean, Abudance, Predation pressure

Judul: Penyelesaian Masalah Rotasi Aliran Fluida Kental Von Karman Menggunakan Metode Homotopi
Abstrak: Von Karman equation is an equation that describes fluid viscous flow induced by infinite disk rotation. By assuming steady flow and laminar, viscous incompressible fluid flow is represented in Von Karman equation by an angular velocity and the vertical direction velocity as the independent variables. Von Karman equation is a nonlinear problem that is solved using the homotopy method. The use of homotopy method is done by defining an homotopy function that requires auxiliary parameters to control the convergent region of the solution. The solution is a recursive formula with given initial conditions. Using software based-functional shows that velocity components converge to a value.
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