Kingdom:   Animalia
Family       Lygaeidae
SubFamily         Lygaeinae
Genus        Arocatus
Species      A. rusticus
Binominal name: Arocatus rusticus
Synonym:  A. ruficollis
Common name:  Milkweed Bug. Swan plant bug

Arocatus rusticus is an insect originally from Australia and is now found in NZ, as far south as Central Otago.
It has a body length of 10mm. The adults have the body that orange-red with dull black colours. Head is large and triangular with relatively large raised eyes. Their antennae and legs are black in colour. The front of the thorax red/orange and rear half is a dull black.
The nymphs and adults feed on seeds of swan plant (Asclepias physocarpa), Tweedia (a genus of flowering plants in the Apocynaceae family) and on Parsonsia (Apocynaceae) by sucking their sap.
The Asclepias plants have supposed to have evolved the toxic sap to guard against the plant-eating insects. However, it seems that these insects have evolved the mechanisms to overcome the toxin and store it in their own body and have become non-eatable too. Another thing they have done is evolve warning colours to warn off predators. They can now feed freely on the plants without fear of predators. The adults hibernate amongst dead leaves and under tree bark.

An adult with wings folded.
Arocatus rusticus Swan plant bug-001.JPG

Arocatus rusticus Swan plant bug.JPG 

A photo of the last instar.
Instar swan plant bug.jpg

Thanks to Wikipedia for text and information: