Fig. 9. Birefringence measurements versus strain for supercontracted MA silk from Nephila (A)The complete data set and (B) the average behaviour of the data set. Predicted values were averaged from all the curves for which a value was available. Filled squares represent values averaged from all seven tests and open squares represent values averaged from all tests for which a value at that extension was available. The numbers above each data point represent the number of curves included in the average. The calculated average behaviour is fitted to the linear regression, y=0.0456x²+0.0197, r²=1. Error bars are one standard deviation. Each sample was from a different spider.