(14 July 2017) Google ‘scale insects’ and you will be presented almost only pages about pesticides. But: these extraordinary creatures are Aussie natives, who deserve our respect and admiration.
Scale insects come in two variations: armored scales and soft scales (often called mealy bugs). The former grow beneath wax covers, shaped like shells. The shield forms a protective cover, almost hiding the fact that it is an insect: it is an adult female scale, which is immobile and permanently attached to the plant she has parasitized. The waxy coating is her defense.
Scale insects shows high degrees of sexual dimorphism. The first instars (hatchlings of insects) emerge from the eggs with functional legs, allowing them to escape the protective scale of mum. These “crawlers” find a place to settle down, feed and lose their legs (if female), or develop wings and fly away (if male). So, the female scale insects retain the immature external morphology even when sexually mature, a condition known as neoteny. Adult males on the other hand have wings (needed to find an attractive female), but that privilege comes with a heavy price: they die within a day or two, where female easily survive an entire winter. Cheap success versus smart survival….
I was lucky to find this one last week in my own garden. So plenty of time to take photos. F/7.1 was enough, 1/200 second and flash. The main challenge was to get a bit of natural looking background…. just moving the branch to a convenient position. She didn’t mind (and can’t walk away anyway….).