Figure 1.

(a) Carausius morosus stick insects vary by over two orders of magnitude in mass between first instars and adults. (b) The physical properties of the secretion were determined with a custom-made set-up. (c) Interference reflection microscopy image of a droplet of the pad secretion deposited on glass, recorded at 30°C. Interference fringes indicate fixed height increments and can thus be used to estimate the contact angle and surface tension of the pad secretion. (d) When a contacting pad is slid rapidly to expose the secretion film, thermodynamic instabilities lead to dewetting; dry patches nucleate within the thin continuous film (dotted circle), then grow (dashed circle) and finally merge (full circle). The speed of dry patch growth is inversely proportional to the secretion’s viscosity.