The beetle is the Native Bronze Beetle (Eucolaspis brunneus). It will indeed cause a lot of visible and cosmetic damage to Metrosideros, but this damage is of no concern to the plant’s health. The tree will grow new leaves within a month or two. Bronze beetles fly in the spring months and have a tendency to occur in large numbers. They lay eggs on the soil, when the eggs hatch tiny larvae or beetle grubs tunnel into the soil and feed on the roots of the same plant – during autumn and winter. The larvae therefore restore the imbalance (root/foliage ratio) caused by the adults.