Defense by foot adhesion in a chrysomelid beetle (Hemisphaerota cyanea): Characterization of the adhesive oil

The beetle Hemisphaerota cyanea, when disturbed, secures a tight foothold on the substrate, whereby it is able to resist pulls of upward of 200 times its body mass. The grip is mediated by thin film adhesion, through use of an oil, which wets the contact pads at the tips of the 60,000 tarsal bristles of the beetle. We have found the oil to consist of a mixture of C₂₂ to C₂₉ n-alkanes and n-alkenes, providing additional support for the notion that tarsal oils are mixtures reflective of the general cuticular hydrocarbon output of insects.