Brochosome size variation and its influence on leafhopper (Hemiptera: Cicadellidae) wing wettability

Insect wing surfaces have nano- and microscale features that enable multi-functionality. Leafhoppers (Hemiptera: Cicadellidae) are unique in that they produce and excrete nanoscale particles, called brochocosomes, that are spread onto the integument by the insect. Brochosomes are extra-cuticular, removable, and make the integument both superhydrophobic and anti-reflective, 2 greatly desired properties in engineering and material science fields. Adaptations like this have captured the interest of researchers looking to draw inspiration from the natural world to create novel solutions and optimize current technologies. Here, we compare brochosome size and wettability across 8 species of leafhoppers using scanning electron microscopy and microgoniometry. We demonstrate that brochosome size is variable within species and that size and wettability are both significantly impacted by species. We report the extent of variability in each case and examine the relationship between brochosome size, body length, and hydrophobicity. In discussing potential applications for brochosomes, we comment on an emerging and rapid analysis technique for evaluating small biological particles. Additionally, we discuss a few recent brochosome-inspired designs and comment on important considerations. Our work provides valuable insight on a unique system that can guide the design of functionalized materials with enhanced hydrophobic and self-cleaning properties.