Size and distribution of wing cells in S. gregaria hind wings.
(a) Typical structure of a hind wing, showing the distribution of the wing cells’ major axis length. Cells with smaller major axis lengths are mostly arranged around the perimeter of the wing (CCL: critical crack length). (b) Mean frequency of wing cell sizes from six hind wings. The distribution of cells corresponds very well to a normal distribution around a mean major axis length of 1.103 mm (σ = 544.16, a = 7.33, R = 0.98). The cumulative membrane area formed by cells smaller than the critical crack length is 19.44% of the overall membrane area (mean ± SD, N = 5553 cells from 6 wings). The colour map of the bars corresponds to subfigure A. (c) 2D-Histogram showing the relative frequency of cell size and their distance to the wing edge. There is a significant positive correlation of the major axis length with the distance to the wing edge (ρ = 0.393, R2 = 0.154, p<0.001, linear correlation, N = 5553 cells).