Body color polymorphism in Nephila maculata: a study of genetic and selection mechanisms. (NSC 90-2311-B-029-004)


In this study we examined whether food composition affects dragline silk gene expression of the giant wood spider Nephila pilipes thus changes the amino acid silks were collected from eight N. pilipes populations in Taiwan to see whether a spatial variation in amino acid composition of dragline silks also existed. The prey compositions of four of the populations were also compared. Although individual N. pilipes in the field ingested different prey, their dragline silk composition did not exhibit significant variation. Amino acid composition of dragline silks collected from four populations whose prey composition were available also showed no significant difference. However, a significant variation was found when dragline silks collected from eight populations were compared. Among the amino acids compared, only glutamate and glycine exhibited significant difference but the variations only ranged from 1% to 2%. The observed variation might resulted from rapid evolution of spidroin genes. While Nephila can alter web structure and silk output in responding to foraging variation, their dragline silk protein seemed to be optimized to a fixed composition.

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