Stress/Strain Characteristics and Biochemical Correlates of Spider Silks

We examined the stress-strain characteristics of dragline silks from a range of spiders and found large inter and intraspecific differences. Moreover, we observed daily variability in silk from individuals of Nephila edulis and we can show that spider condition (starvation) affected silk properties, in particular that it tended to decrease breaking elongation. Reeling speed significantly affected silk properties in both Nephila edulis and Araneus diadematus, such that with increasing speed (1) breaking elongation decreased, (2) breaking stress increased and (3) Young's modulus increased. Analysis of our data from the different reeling speeds indicates that Nephila and Araneus dragline silks differ in basic properties.