Research of the mechanical property, gene expression, and behaviroal ecology of spider silk. (2/3) (NSC 92-2311-B-029-002)
Recent studies have demonstrated that orb weaving spiders may alter web structures, foraging localities or silk output in response to prey variations. In this study we conducted field surveys and food manipulations to examine whether orb weaving spiders may also adjust the protein of silk to prey variations. A comparison of dragline silks collected from nine giant wood spider Nephila pilipes populations in Taiwan showed a spatial variation. The percentages of all but alanine and glycine exhibited significant differences among populations. A survey of prey composition also revealed a significant spatial variation among N. pilipes populations. To determine whether prey variation was responsible for silk protein variation, we fed N. pilipes with different types of prey (dipteran vs. orthopteran) then compared the percentages of five major dragline amino acids and secondary structures. The results showed that dragline of N. pilipes fed with orthopteran prey contained significantly higher proline and glutamine but lower alanine. In congruent with this result were those from FTIR spectroscopy, which showed that dragline of N. pilipes fed with crickets exhibited significantly higher percentages of proline and glutamine-containing β turn and lower percentages of alanine-containing β sheet structures. Since the results of feeding manipulations showed that diet significantly affected the compositions of dragline silks, the observed spatial variation seemed to be resulting from different type of prey these spiders had consumed. Results of this study thus indicated that orb weaving spiders can alter dragline protein in response to prey variations.
Updated: Jan-24-2014 11:34:24 (Taiwan, GMT+08:00).