Fig. 8. Birefringence measurements versus strain for supercontracted MA silk from Araneus. (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 circles represent values averaged from all nine tests and open circles 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 curve is fitted to the second order polynomial, y=0.0122x+0.0070, r²=0.99. Error bars are one standard deviation. Each sample was from a different spider.