T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Hoppers (Blue Planthopper) Siphanta acuta

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Auchenorrhyncha
Infraorder: Fulgoromorpha
Superfamily: Fulgoroidea
Family: Flatidae
Genus: Siphanta
Species: S. acuta
Binomial name: Siphanta acuta (blue form)
Common name: Blue planthopper, torpedo bug

Siphanta acuta is a plant-feeding insect.  Originally from Australia, this species has spread with the unintentional help of man. They are about 15 mm long and they resemble small leaves and are generally found in trees. Their wings are triangular, and the back edge and corners of their wings are lined with dotted red. 
Its eggs are approximately 1.2 mm long. Groups of more than a 100 eggs are laid in a sub-circular pattern about in 5 mm) diameter on the stems or leaves of plants. Eggs on the margin of the clutch are laid flat while eggs in the centre of the clutch are more upright giving the egg mass a dome-like shape. The egg mass is glued together and partially covered by a dark, semi-transparent cement produced by the adult female. Eggs hatch in 10 to 20 days.
This bug has five nymphal stages, called instars that are each separated by moults. Moulting usually occurs at night or in the early morning. Adults live for about two months.
Like most homopteran insects such as aphids, mealy bugs and scales, planthoppers produce honeydew. The honeydew of the green planthopper is a dark bluish-green, sweetish, transparent liquid. Its colour is influenced by its host plant. A black fungus, sooty mould, grows quickly on the exuded honeydew which, in heavy infestations, blackens the leaf, decreases photosynthesis activity, decreases vigour and often causes disfigurement of the host.

It is thought that the blue colouration might occur in two different ways: environmental (a change in diet or habitat) or genetic via a recessive gene.

An adult blue Siphanta acuta. Photographed New Plymouth January.

An adult green form of Siphanta acuta

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/