Scale insect
Ecology
Scale insects are an ancient group, having originated in the Cretaceous, the period in which angiosperms came to dominance among plants, with only a few groups species found on gymnosperms. They feed on a wide variety of plants but are unable to survive long away from their hosts. While some specialise on a single plant species (monophagous), and some on a single genus or plant family (oligophagous), others are less specialised and feed on several plant groups (polyphagous). For example, cochineal species are restricted to cactus hosts, and the gall-inducing Apiomorpha are restricted to Eucalyptus. Some species have certain habitat requirements; some Ortheziidae occur in damp meadows, among mosses and in woodland soil, and the boreal ensign scale (Newsteadia floccosa) inhabits plant litter. A Hawaiian mealybug Clavicoccus erinaceus that fed solely on the now critically endangered Abutilon sandwicense has gone extinct as has another species Phyllococcus oahuensis. Several other monophagous scale insects, especially those on islands, are threatened by coextinction due to threats faced by their host plants.
Scale insect-15