The adhesive substance produced by flypaper plants, Roridula gorgonias, is extremely sticky, long lasting, and water tolerant. They remain hydrated and functionally adhesive even after prolonged exposure to dry environments. Flypaper plants also cultivate populations of symbiotic insects within its traps that must be able to resist the adhesive. The insect’s shells are uniformly coated with a specific type of grease rendering the adhesive powerless to trap them. Other insects tend to produce more patchy grease layers that leave room for the adhesive to stick to their exposed cuticle.
“It has been previously demonstrated that the secretion of R.[Roridula] gorgonias differs remarkably from the aqueous mucilage of flypaper traps of other carnivorous plants belonging to the genera Byblis, Drosera, Drosophyllum, and Pinguicula. Various triterpenoids, acylglycerides, and flavonoids have been found in the R. gorgonias adhesive secretion. The secretion is water-insoluble and capable of maintaining ovoid or spherical shape and adhesive properties even under water. The pellucid secretion droplets have been observed to retain their properties for an indefinitely long time on dead and dried-up leaves or even on leaves preserved in formalin. The secretion remained adhesive and viscoelastic even after storing dead, dry R. gorgonias plants for 5 years.” (Voigt and Gorb 2010: 1511)
“Resinous secretion of R. gorgonias seems to be responsible for several functions: (1) The mixture of triterpenoids and acylglycerids causes its consistency similar to sticky syrup or to so-called pseudoliquid phase similar to that observed in commercial pressure-sensitive adhesives. Such consistency of secretion probably contributes to its visco-elastic properties. The resin obviously functions as the adhesive component of the efficient insect trap. (2) Since resin droplets, released on trichome tips, are shiny and glistening, they attract insects prior to their capture. (3) As mentioned earlier, such a shiny surface also enhances light reflection therewith supporting the reduction of leaf temperature in a hot environment. (4) The hydrophobic nature of the secretion results in the reduction of water loss. (5) The robustness of the secretion to abiotic environmental factors could lead to saving energy, because of lower glandular activity necessary to fulfill the aforementioned functions. The renewal of the secretion is very limited, as we have observed in previous studies on adhesion of R. gorgonias trichomes. (6) Glandular trichomes may additionally offer protection against predatory insect attacks and animal grazing.” (Voigt and Gorb 2010: 1514)