Figure 1.

Secretion droplets from adult beetles L. decemlineata on a glass slide. The beetles' legs are rubbed against the slide, which results in a strong shear that is able to deposit the secretion on the surface. The typical size of the droplets is a few microns. A home-made microneedle, mounted on a three-axis micromanipulator, was used to draw up the secretion droplets spread on the glass slide. The tip was moved onto the slide surface to collect the largest amount of secretion. Owing to capillary effects, the rise of the liquid takes place spontaneously inside the capillary tube. Scale bar, 10 µm.