Learn more about the lifecycle of scale insects. Researcher Rosa Henderson, of Landcare Research NZ Ltd, describes the development of these tiny creatures.
With scale insect females, they are called eggs, nymphs and final instar nymph, but the final instar nymph is a neotenic or larval-form adult. She never grows into something like a beetle or a fly. The first instar is usually the crawler stage, and that has legs and its dispersal. Some scale insects lose their legs at the second instar so therefore they are fixed to their plant. The little males go through the first two instars the same as the females, and then they go into the non-feeding stages, which is firstly called a pre-pupa and then a pupa, and then they emerge as an insect-looking creature, but they have no mouth parts, so they don’t feed and only live a few days. Just long enough to mate with a female and that's it. The scale insects are producing the honeydew until they are mature adults. The adult females do not feed any more and so they are out of that system, but they are continually producing young, which set up and settle on to the trees and start producing honeydew straight away and through their 3 or 4 life stages are producing honeydew.
Landcare Research New Zealand Limited