Table 2.

Characteristics of the dragline silk produced by the ampullate major gland, and of the spiral thread silk produced by the flagelliform gland in the spider Aranea diadematus. Composition and structure of the silk threads and mechanical properties under tension. See references for experimental protocols

Characteristic of the silk	Silk type		References
Molecular weight (kDa)	Fibroin (spidroin)	Up to 350	Ayoub et al. (2007)
Composition in main amino acids	Dragline	Glycerin, alanine, proline, glutamic acid, serine	Andersen (1970)
Structure of the fiber	Core of fibril's structure	Simple	Du et al. (2011)
	Thread diameter	3 to 5 µm	Du et al. (2011)
Ultimate tensile strength of the silk fiber (GPa)	Dragline	1.1 to 1.2	Pérez-Rigueiro et al. (2000); Du et al. (2011)
	Spiral thread	0,3	(Pérez-Rigueiro et al (2000).; Du et al. 2011)
Strain at break (%)	Dragline	20 to 27	Pérez-Rigueiro et al. (2000); Du et al. (2011)
	Spiral thread	270	Pérez-Rigueiro et al. (2000); Du et al. (2011)
Stiffness (GPa)	Dragline	10	Pérez-Rigueiro et al. (2000); Du et al. (2011)
	Spiral thread	0.003	Pérez-Rigueiro et al. (2000); Du et al. (2011)
Toughness (MJ.m−3)	Dragline	180	Pérez-Rigueiro et al. (2000); Du et al. (2011)
	Spiral thread	150	Pérez-Rigueiro et al. (2000); Du et al. (2011)
Density (g.cm−3)	Dragline	1.3	Romer et al. (2008)
	Spiral thread	1.3	Romer et al. (2008)