Surface Structure and Wetting Characteristics of Collembola Cuticles

Abstract

The cuticles of the arthropods Collembola (springtails) are known to be superhydrophobic, displaying such properties as water-repellence and plastron formation; overhanging surface structures have been suggested as the source of these properties. Superhydrophobicity is closely related to surface structuring and other surfaces with overhanging structures have been shown to possess robust superhydrophobic properties. In effort to correlate the wetting performance and surface structuring of the cuticles, from both a technical and evolutionary point of view, we investigated a selection of Collembola species including species from several families and covering habitats ranging from aquatic to very dry. The observed contact angles of wetting was in general larger than those predicted by the conventional models. Not all the studied Collembola were found to have superhydrophobic properties, indicating that superhydrophobicity is common, but not a universal trait in Collembola. Overhanging structures were found in some, but not all Collembola species with superhydrophobic cuticles; which leads to the conclusion that there is no direct link between overhanging surface structures and superhydrophobicity in Collembola.

The springtail cuticle as a blueprint for omniphobic surfaces

“…103,130 To avoid wetting, most springtails exhibit a superhydrophobic surface (Fig. 34,103,131,132 Recently, Gundersen et al reported that the littoral Collembola Cryptopygus clavatus lives submerged in summer and respires through direct gaseous exchange with water lacking any support of a plastron. This leads to the formation of a protective air layer upon immersion, the plastron, forming a gas reservoir that enables regular gaseous exchange under water ( Fig.…”

“…[143][144][145] The unique ornamentation typically consists of nanoscaled primary granules (minor tubercles) and interconnecting ridges; together forming nanocavities that are arranged in a rhombic or hexagonal comb-like pattern, which covers the entire body (Fig. 130,131 In addition, the comb structure exhibits characteristic overhangs in a cross-sectional view. Several studies showed that the nanoscopic comb structures are rather similar, reflected in the diameter of the cavities between 0.3 and 1 mm.…”

“…103,146 At the microscopic scale, some species that live primarily in soil possess papillose secondary granules (major tubercles) that are completely decorated by the comb structure. 112,130,131,144,148,149 130,145 Thin bristles (setae) or scales form the tertiary structure complete the hierarchical assembly of the collembolan cuticle.…”

Viaticene A – An Unusual Tetraterpene Cuticular Lipid Isolated from the Springtail Hypogastrura viatica

“…Springtails (Collembola) are small, wingless, soil‐dwelling hexapods that consist of approximately 8,700 species found throughout the world . The cuticles of springtails are robust, non‐fouling, self‐cleaning, and super‐hydrophobic surfaces that protect these arthropods from harsh soil conditions . Recent work has shown that the cuticular surfaces of springtails are not only water‐resistant but are also able to withstand wetting from several low surface tension liquids .…”

Double cuticle barrier in two global pests, the whiteflyTrialeurodes vaporariorumand the bedbugCimex lectularius

“…They erect a composite barrierthe cuticle -at the apical side of their epidermis that protects them against these hazards. The first, physical barrier in penetration protection is constituted by cuticle nanostructures and macrostructures protruding at their surface (Watson et al, 2010;Sun et al, 2012;Gundersen et al, 2014;Darmanin and Guittard, 2015). The material properties of the second inward barrier are to a large extent defined by lipophilic compounds including waxes and free cuticular hydrocarbons (CHCs) at the cuticle surface (Ramsay, 1935;Noble-Nesbitt, 1970;Gibbs, 1998;Rourke and Gibbs, 1999;Gibbs, 2002;Moussian, 2010;Gibbs, 2011).…”