Spider in high mountainous areas of Taiwan: a study of silk gene diversity.

Abstract

High mountains are unique ecosystems in Taiwan and the environmental conditions in such habitats are harsh to inhabiting organisms. High mountain ecosystems are characterized by dramatic temperature changes, low concentration of oxygen, frequent strong wind and intensive UV radiation. Such unique ecosystems provide a good opportunity to study adaptation of organisms inhabiting such harsh environments. Spiders use several kinds of silk glands to produce silks for various purposes, and these silks exhibits different composition and properties. Composed of protein fibers, spider silk has higher strength and elasticity than most of artificial fibers. Currently, it is not clear harsh environmental conditions in high mountains facilitate the evolution of silks with special properties. The first goal of this study is to quantitatively collect and compare the spider diversity in high and low elevation areas in Taiwan. Various environmental variables will be measured to realize factors responsible for the differences in spider diversities between habitats of various elevations. The second goal of this study is to investigate the evolution of silk genes of spiders inhabiting high mountains by comparing the molecular structures, physical properties and ecological functions of silks produced by species inhabiting low and high elevation habitats. Results of this study will help realize how the unique alpine ecosystems may have shaped the compositions and structure of spider skills. Currently we had established sampling plots (10 m × 10 m) in Lianhuachin (< 1000 m), Renlun (1500 m–2000 m), Rueiyanshi (2000–2500 m), Yuanfong (2500 m–3000 m) and Hehuan mountain (> 3000m). Three field trips had been conducted and the data from the first field trip was analyzed. Preliminary results show that species richness and evenness were significantly higher in mid and low elevation broadleaf foresees, followed by mid-high elevation mixed forests, and were the lowest in high mountain prairie. The spider guild composition was more or less homogenous in mid and low elevation forests, dominated by weaving spiders. However, as elevation increased the dominance by wondering spiders also increased. Although weaving species were not abundant in high elevation (> 3000 m) habitats, species from Agelenidae and Araneidae could be found. In the near future we will complete field collections and begin analyzing the genetic characteristics and physical properties of the aforementioned high elevation spider species.

High mountains are unique ecosystems in Taiwan and the environmental conditions in such habitats are harsh to inhabiting organisms. High mountain ecosystems are characterized by dramatic temperature changes, low concentration of oxygen, frequent strong wind and intensive UV radiation. Such unique ecosystems provide a good opportunity to study adaptation of organisms inhabiting such harsh environments. Spiders use several kinds of silk glands to produce silks for various purposes, and these silks exhibit different composition and properties. Composed of protein fibers, spider silk has higher strength and elasticity than most of artificial fibers. During the evolution of Araneae, there were several major changes in the silk synthesis systems. Under strong selection pressures, a high diversity in molecular structures, physical properties and ecological functions of silks is generated. Spiders exhibit high species diversity and they can be further classified into various foraging guilds according to their prey catching behaviors. Currently, it is not clear whether the silks in different foraging guilds differ in chemical composition, physical properties and molecular structures. Nor do we realize whether the harsh environmental conditions in high mountains facilitate the evolution of silks with special properties. The first goal of this study is to quantitatively collect and compare the spider diversity in high and low elevation areas in Taiwan. We will also measure various environmental variables to realize factors responsible for the differences in spider diversities between habitats of various elevations. The second goal of this study is to investigate the evolution of silk genes of spiders inhabiting high mountains. We will compare the molecular structures, physical properties and ecological functions of silks produced by species inhabiting low and high elevation habitats. Results of this study will help realize how the unique alpine ecosystems may have shaped the composition and structure of spider silks.

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Updated: Jan-24-2014 11:34:24 (Taiwan, GMT+08:00).