1 Landcare Research, Glen Innes, Auckland
Most beetles keep their surfaces free of particulate matter by active grooming, or simply having slick and smooth cuticular surfaces. Many species, however, may be coated by films of fluids of various viscosities and/or coarse to fine particular material, some of it embedded in waxy material or encrustations. The fluids or waxy secretions that form films or cements are produced from glands within the bodies of the beetles, often distributed by special grooves and attachment accomplished by passive or active methods, held in place often by special setae. The exact mechanisms of secretion and attachment are poorly known and have not been fully characterised or described for beetles. Here a brief and rather ad hoc survey of encrustations is presented and examined in some beetle groups to determine their evolutionary and behavioural significance.