Judul: Diversity and Abundance of Insect Pollinators in Different Land Use Types in Jambi, Sumatra
Abstrak: Indonesia is one of the tropical countries with high biodiversity. Recently, the biodiversity of plants and animals is declining due to forest converting to settlements, mines, agricultures, and plantations. In Central Sumatra including Jambi, annual deforestation rate reaches 3.2%-5.9%. Converting natural landscapes to agricultural land affects insects biodiversity, including insect pollinators. The research aimed to study diversity and abundance of insect pollinators in different land use types, i.e. oil palm plantation, rubber plantation, and jungle-rubber in Jambi, Sumatra. Observation and collection of insect pollinators were conducted from November until December 2012 at Bejubang, Batanghari regency, Jambi province. Insect observations were conducted in understory plants at three land use types, i.e. oil palm plantation, rubber plantation, and jungle-rubber. Scan sampling method was employed to explore the diversity and abundance of insect pollinators at 08.00-10.00 and 14.00-16.00 in sunny days. This study consist of found 1308 individuals of insect pollinators, belonging to 54 species,7 families, and 3 orders (Hymenoptera, Diptera, and Lepidoptera). Number of species and individual of insect pollinators found in oil palm plantation (43 species, 561 individuals) and rubber plantation (40 species, 650 individuals) were higher than jungle-rubber (7 species, 97 individiuals). Giant honey bee (Apis dorsata) and stingless bee (Trigona sp. (=aff. T. planifrons)) were abundant in oil palm plantation, while stingless bee (T. laeviceps) and small carpenter bee (Ceratina lieftincki) were abundant in rubber plantation. Whereas, hoverfly (Syrphidae sp5) was abundant in the jungle-rubber. The abundance and species richness of insect pollinators in the morning were higher than in the afternoon. Diversity and evenness of insect pollinators in oil palm and rubber plantations were higher than jungle-rubber. The abundant of flower of understory plants in oil palm and rubber plantations indicated insect pollinators forage in those locations. Meanwhile, jungle-rubber and rubber plantations were prefered by insect pollinators for nest building, because there were many large trees, branches, and broken twigs. The insect pollinators community in oil palm plantation and rubber plantation were more similar than in oil palm plantation and jungle-rubber, or in rubber plantation and jungle-rubber.
Keyword: Apidae, Halictidae, insect pollinators, Megachilidae, Syrphidae

Judul: Keanekaragaman Ordo Hymenoptera di Perkebunan Kelapa Sawit, Perkebunan Karet dan Hutan Karet di Jambi
Abstrak: There were much deforestations from primary forest to rubber and oil palm plantation in Jambi. Some taxa could be bioindicator, for example is Hymenopteran insects. This research purposed to study the diversity of Hymenoptera in oil palm plantation, rubber plantation and jungle rubber in Jambi. Insect collected by using insect net at 7 to 11 am. The environment parameters measured were temperature, humidity, and light intensity. In three vegetation habitats and villages adjacent Hutan Harapan, Jambi were found six families of Hymenoptera, i.e. Apidae, Halictidae, Megachilidae, Pompilidae, Sphecidae and Vespidae. Highest abundant found were Apis and Trigona. Endemic species found was Trigona minangkabau. The highest diversity of Hymenoptera was found in oil palm plantation (16 species), and the less diversity was in rubber plantation and village (9 species). Generally, number of species of Hymenoptera didn’t correlated significantly with temperature, light intensity and humidity.
Keyword: diversity, Hymenoptera, oil palm plantation, rubber plantation, jungle rubber

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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