Judul: Aktivitas masuk-keluar sarang dan pembentukan sel madu pada Trigona itama Schwarz (Hymenoptera: Apidae)
Abstrak: Penelitian ini bertujuan mempelajari aktivitas masuk-keluar sarang dan proses pembentukan sel madu pada Trigona itama. Pengamatan aktivitas masukkeluar sarang T. itama dilakukan selama 10 hari, pada pukul 07.00-17.00 WIB. Proses pembentukan sel madu diamati dan diukur tinggi serta diameternya. Penelitian menunjukkan puncak aktivitas harian masuk dan keluar sarang terjadi pada pukul 11.00 WIB dengan rata-rata 17 individu/menit. Aktivitas terbang membawa polen yang tinggi (3 individu/menit) terjadi pada pukul 07.00-09.00 WIB. Secara umum, suhu berkorelasi positif terhadap aktivitas terbang harian, sedangkan kelembapan udara berkorelasi negatif. Pembentukan sel madu diawali dengan pengumpulan bahan, dilanjutkan dengan pembentukan pondasi dan kerangka, pembuatan sel madu, pengisian madu, dan penutupan sel. Pembentukan sel madu memerlukan waktu sekitar empat minggu. Sel madu T. itama dengan tinggi 28 mm dan diameter 19.44 mm.
Keyword: daily activity, environmental factors, honey cells, Trigona itama

Judul: Aktivitas keluar-masuk sarang dan pollen load pada "Teuweul Omas", Tetragonula sp. (Hymenoptera: Apidae)
Abstrak: Tetragonula merupakan anggota lebah tak bersengat penghasil madu dan propolis yang produktivitasnya dipengaruhi aktivitas terbang lebah pekerja. Salah satu faktor yang mempengaruhi aktivitas terbang lebah pekerja ialah ketersedian pakan dan lingkungan. Penelitian ini bertujuan menghitung aktivitas keluar-masuk sarang dan mengukur pollen load pada “teuweul omas”. Pengamatan aktivitas keluar-masuk sarang pada “teuweul omas” dilakukan selama 30 hari, pada pukul 06.00-18.00 WIB selama 1 menit dengan interval waktu 1 jam. Polen yang berasal dari pollen basket dan sel sarang dianalisis menggunakan metode acetolysis. Hasil penelitian menunjukan “teuweul omas” telah melakukan aktivitas keluar-masuk sarang pukul 06.00 WIB (8 individu/menit), meningkat pada pukul 12.00-13.00 WIB (10 individu/menit masuk dan 9 individu/menit keluar sarang), dan menurun pada pukul 17.00-18.00 WIB (2 individu/menit keluar-masuk sarang). Aktivitas keluar-masuk sarang berkorelasi positif dengan suhu dan intensitas cahaya, serta berkorelasi negatif dengan kelembapan. Korelasi yang signifikan terjadi antara faktor lingkungan (suhu, kelembapan dan intensitas cahaya) dengan aktivitas masuk sarang membawa air atau nektar (r = 0.779, p = 0.003), (r = -0.799, p = 0.002), (r = 0.776, p = 0.003), dan keluar sarang membawa sampah (r = 0.888, p = 0.000), (r = -0.876, p = 0.000), (r = 0.782, p = 0.003). Sebanyak 14 jenis polen yang berasal dari pollen basket dan sel sarang berhasil diidentifikasi, yaitu polen dari tumbuhan Caesalpinia pulcherrima, Portulacaceae, Carica papaya, Sapindaceae, Compositae, Chlorantaceae, Cocos nucifera, Pinaceae, Solanaceae, Liliaceae, Umbelliferae, Polygonaceae-1, Polygonaceae-2, dan Leguminosae. Rata-rata pollen load pada “teuweul omas” sebanyak 19 475.7 butir polen.
Keyword: acetolysis, pollen basket, stingless bees, Tetragonula

Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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