Toxicity of poison from spider Nephila sp.

Toxicity of poison from spider Nephila sp. to Aëdes aegypti L. larvae

YAYAN SANJAYA♥, TINA SAFARIA

Program Studi Biologi FPMIPA, Universitas Pendidikan Indonesia (UPI), Bandung 40154

ABSTRACT

A research about the toxicity of poison from spider Nephila sp. unto larvae of Aëdes aegypti L. had been done. The objectives of this research were to get the information about the toxicity of poison from spider Nephila sp. into larvae A. aegypti. The experiment method of this research was using Randomized Complete Block Design. This experiment used all of four instars of A. aegypti larvae. The experiment of each instar had been done with six treatments of the lethal concentration from spiders poison. Those six treatments were 1%, 10%, 25%, 50%, 75% and 100%. Each treatment had four replications. The result of this research showed that poison from spider Nephila sp. is toxic unto the larvae of A. aegypti. The average of lethal concentration for the first instar is 13.11%, for the second instar is 28.16%, for the third instar is 41.46% and for the fourth instar is 63.09%.

Key words: toxicity, lethal concentration (LC50), spider Nephila sp. and larvae of Aëdes aegypti L.

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A Fossil Wood of Dipterocarpaceae

A Fossil Wood of Dipterocarpaceae from Pliocene Deposit in the

West Region of Java Island, Indonesia

YANCE I. MANDANG1, NORIKO KAGEMORI

1 Forest Product Research and Development Center, Bogor 16610, Indonesia.

2 Wood Research Institute, Kyoto University, Uji, Kyoto 6110011, Japan.

ABSTRACT

Fossil woods in Java Island have been excavated and sold for outdoor ornaments or indoor decoration purposes since 30 years ago. These fossils are in danger of being drained out without known identities, composition and history. This study was aimed to find out the botanical identity and geographical aspect of a newly recovered silicified fossil wood from Banten area in the west region of Java Island. The fossil trunk 28 m in length and 105 cm in diameter was buried in a tuffaceous sandstone layer. The age of the stratum was thought to be Lower Pliocene. A small sample was cut from the outer part of the log and then ground to obtain thin section for anatomical observation. The main anatomical features of the fossil wood are as follows: wood diffuse porous; vessel almost exclusively solitary, vascicentric tracheid present; axial intercellular canal present, distributed in long tangential rows; fibers with distinctly bordered pit. These features show affinities of the fossil wood to the extant wood Dryobalanops of the family Dipterocarpaceae, regardless of the fact that this genus is no longer exists living in the natural forest of the present day Java Island.

Keywords: fossil wood, Dipterocarpaceae, Dryobalanoxylon, Pliocene, Java Island.

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Precision of Nest Method in Estimating Orangutan Population

Precision of Nest Method in Estimating Orangutan Population and Determination of Important Ecological Factors for Management of Conservation Forest

Yanto Santosa* dan Dede Aulia Rahman

Departemen Konservasi Sumberdaya Hutan dan Ekowisata, Institut Pertanian Bogor, Kampus IPB Dramaga, Bogor 16680

Abstract

Orangutan as an umbrella species is closely interlinked with sustainable forest management meaning that the protection of this species has implications on the protection of other species and maintain ecosystem stability. The total natural habitat required to support orangutan’s population could only be determined by the appropriate population size. It is associated with the carrying capacity to accommodate or fulfill the habitat requirements of a wildlife population. Selection and delineation of core and wilderness zones as habitat preference should be based on the results of preference test shown by the spatial distribution of orangutan population. Value of the coefficient of variation (CV) was used to observe the precision of the population estimation and to identify important ecological factors in selection of nesting trees. The study resulted in varied CV spatial values for various habitat types: 22.60%, 11.20%, and 13.30% for heath, lowland dipterocarp, and peat swamp forest, respectively. In the other side, CV temporal values for various habitat types were 5.35%, 22.60%, and 17.60% for heath, lowland dipterocarp, and peat swamp forest, respectively. This indicated that the population density in each type of forest ecosystems had a variation based on location and did not varied according to time of survey. The use of nest survey technique showed good reliable results in estimating orangutan population density. Efforts to improve the precision of estimation can be done by formulating r value as the harmonic average of nest production rates and t as the average of nest decay time per nest category. Selection of habitat preference and nest trees were influenced by food availability thus should form important consideration in conducting nest survey to avoid bias in estimating orangutan populations.

Keywords: conservation forest management, nest survey, orangutan, population size, ecological factors


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