Pruinescence/ˌpruːɪˈnɛsəns/,[1] or pruinosity, is a "frosted" or dusty-looking coating on top of a surface. It may also be called a pruina (plural: pruinae), from the Latin word for hoarfrost.[2][3] The adjectival form is pruinose/ˈpruːɪnoʊs,-z/.
Entomology
In insects, a "bloom" caused by wax particles on top of an insect's cuticle covers up the underlying coloration, giving a dusty or frosted appearance. The pruinescence is commonly white to pale blue in color but can be gray, pink, purple, or red; these colors may be produced by Tyndall scattering of light. When pale in color, pruinescence often strongly reflects ultraviolet.[4]
In the common whitetail and blue dasher dragonflies (Plathemis lydia and Pachydiplax longipennis), males display the pruinescence on the back of the abdomen to other males as a territorial threat.[5] Other Odonata may use pruinescence to recognize members of their own species or to cool their bodies by reflecting radiation away.[4]
Plants, fungi, and lichens
The term pruinosity is also applied to "blooms" on plants—for example, on the skin of grapes[6]—and to powderings on the cap and stem of mushrooms, which can be important for identification.
An epinecral layer is "a layer of horny dead fungal hyphae with indistinct lumina in or near the cortex above the algal layer".[3]
^ abPruina as a Taxonomic Character of the Lichen Genus Dermatocarpon, Starri Heidmarsson, The Bryologist
Vol. 99, No. 3 (Autumn, 1996), pp. 315-320, [1]
^ abcCorbet, Phillip S. (1999). Dragonflies: Behavior and Ecology of Odonata. Ithaca, NY: Cornell University Press. pp. 281–282. ISBN0-8014-2592-1.
^Johnson, Clifford (1962). "A Study of Territoriality and Breeding Behavior in Pachydiplax longipennis Burmeister (Odonata:Libellulidae)". The Southwestern Naturalist. 7 (3/4): 191–197. doi:10.2307/3668841. JSTOR3668841.