Tiny, dome-shaped scale insects can damage or kill trees in heavy infestations, but their presence in moderate numbers actually supports a variety of other beneficial insects that protect trees and surrounding vegetation from other pests, a new study shows. Shown here are (left) a branch on an urban willow oak tree (Quercus phellos) that is covered in oak lecanium scales (Parthenolecanium quercifex) and (right) an urban red maple (Acer rubrum) branch covered with gloomy scales (Melanaspis tenebricosa). (Left photo by Clyde Sorenson, Ph.D.; right photo by Caleb Wilson, Ph.D.