Judul: Diversity of Visiting Insect and Pollination Services of Apis cerana and Tetragonula laeviceps (Hymenoptera: Apidae) On Strawberry Plants (Fragaria x ananassa)
Abstrak: Tanaman Stroberi memiliki bunga hermaprodit, namun organ reproduksi betina matang terlebih dahulu dibandingkan dengan jantan, sehingga penyerbukan sangat ditentukan oleh kehadiran serangga. Tujuan penelitian ini adalah mengukur keanekaragaman serangga pengunjung dan jasa polinasi A. cerana dan T. laeviceps pada tanaman stroberi. Varietas stroberi yang digunakan pada penelitian ini adalah sweet charly. Tanaman stroberi yang digunakan dibagi menjadi lima perlakuan, yaitu (1) 50 tanaman stroberi dikurung dengan kassa tanpa diberi koloni lebah (tanaman kontrol), (2) 50 tanaman dikurung dengan bantuan manusia (penyerbukan manual), (3) 50 tanaman stroberi dikurung dengan menambahkan satu koloni T. laeviceps, (4) 50 tanaman terbuka dan ditambahkan satu koloni A. cerana, (5), 50 tanaman terbuka dengan pengamatan serangga penyerbuk alami. Pengamatan aktivitas kunjungan A. cerana dan T. laeviceps dilakukan dengan metode focal animal sampling pada kisaran waktu pukul 08.00-16.00 WITA. Pengamatan aktivitas kunjungan T. laeviceps dilakukan pada tanaman yang dikurung dan A. cerana pada tanaman terbuka. Pengamatan keanekaragaman serangga pengunjung bunga dilakukan dengan metode scan sampling. Pengukuran hasil panen buah dilakukan pada 25 tanaman yang dipilih secara acak dari setiap perlakuan, meliputi jumlah buah, jumlah buah sempurna, jumlah buah abnormal, panjang buah, tebal buah, bobot buah, jumlah biji per buah, kadar gula dan kandungan vitamin C buah. Data pembentukan buah pada masing-masing perlakuan dianalisis menggunakan One-way ANOVA dan dilanjutkan dengan uji Tukey. Hasil penelitian menunjukkan terdapat 11 spesies serangga pengunjung tanaman stroberi yaitu Apis cerana, Xylocopa latipes, Vespa sp. Megachile sp. C. javana, S. balteatus, Hypolimnas bolina, Neptis hylas, Hympolimnas missipus, Ypthima philomela, Eurema hecabe. Berdasarkan pengamatan, durasi kunjungan A. cerana terlama (12,64±0,47 detik/bunga) dengan jumlah bunga yang dikunjungi sebanyak (12,80±0,65 bunga/tiga menit) terjadi pada pukul 08.00-09.00. Pada T. laeviceps, durasi kunjungan terlama (89,15±9,03 detik/bunga) dan jumlah bunga yang dikunjungi sebanyak (2,18±0,22 bunga/tiga menit) terjadi pada pukul 09:00- 10.00 Rata-rata jumlah polen yang dibawa oleh A. cerana (303.275 butir polen) lebih banyak dibandingkan pada T. laeviceps (86.281 butir polen). Penyerbukan dengan bantuan manusia meningkatkan persentase buah sempurna sebesar 76,98%, penyerbukan dengan bantuan A. cerana sebesar 77,31% dan penyerbukan T. laeviceps sebsar 71,70%. Selain itu terjadi peningkatan kandungan vitamin C buah pada penyerbukan oleh A. cerana (60,7% per 100g sampel) dan T. laeviceps (50,85% per 100g sampel), dibandingkan pada tanaman kontrol (38,5% per 100g sampel)., Strawberry plants have hermaphrodite flowers, but the female reproductive organs mature first compared to the male organ, so pollination is largely determined by the presence of insects. This study aims to measure the diversity of visiting insects the pollination services of A. cerana and T. laeviceps in strawberry. The variety of strawberry used in this study was sweet charlie. Strawberry plants used were divided into five treatments, i.e., (a) 50 plants were caged by screen without bee colonies as a control, (b) 50 plants were caged by the screen for hand pollination with pollen from a different plant, (c) 50 plants were caged by screen and added by one colony of T. laeviceps, and (d) 50 open plants added by one colony of A. cerana, (e) 50 open plants with natural insect pollinators. Observation of visiting activity of A. cerana and T. laeviceps were conducted by
Keyword: Jasa polinasi; Apis cerana, Tetragonula laeviceps, Pollination services, Apis cerana, Tetragonula laeviceps, strawberry

Judul: Efektivitas Polinasi Apis cerana Fabricus dan Trigona laeviceps Smith (Hymenoptera: Apidae) pada Fragaria x annanassa Kultivar Earlibrite
Abstrak: Strawberries (Fragaria x annanassa) is herbaceous perennial plant. Pollination of the plant is conducted by wind and insects, especially bees. The purpose of the research were to study pollination effectiveness of Apis cerana Fabricus and Trigona laeviceps Smith in Fragaria x annanassa Ealibrite Cultivar. Effectiveness of pollination of the bees were measured by visiting behavior and fruit set. Visiting behavior of bees were observed based on foraging rate, flower handling time, and total foraging time. Fruit set were measured based on number of normal fruit, number of abnormal fruit, size and weight of the fruits, and vitamin C content. Environmental factors, such as air temperature, humidity, velocity of wind, and light intensity were measured. Peak of foraging activity of A. cerana occurred in the morning, while T. laeviceps occurred in the noon. Foraging rate of A. cerana was 2.8 flowers/minutes, flower handling time was 12.64 seconds, and total foraging time was 14.46 minutes. Whereas, foraging rate of T. laeviceps was 3.23 flowers/minutes, flower handling time was 5.60 seconds, and total foraging time was 7.73 minutes. Pollination of A. cerana and T. laeviceps increase normal fruit, decrease abnormal fruit, increase size and weight of fruits, and vitamin C content.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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