Some native species are "host specific", meaning they can live only on particular plants, for example, the button scales [Lecanochiton species] are only found on pōhutukawa and rātā. Other native soft scales can be found on several different plants, but usually in just one habitat.
Two different soft scale insects are found on Nothofagus species in beech forest:
Some of the exotic species have very wide host plant ranges (they are polyphagous). In areas disturbed by human activity, e.g., bush margins, they can even be found on some native plants, and two of them, soft brown scale and hemispherical scale, have spread a little bit further into native forest.
Eight different types of soft scale insects are found on shrubs, trees and ferns in areas modified by humans (gardens and home orchards):
Chinese wax scale Ceroplastes sinensis Del Guercio