This article was published in The Fringe, March 2013
More Moths & Butterflies -
and the plants they depend on...
The native wire-vine, pohuehue or Muehlenbeckia complexa, which sprawls along our coastline creating a tripping tangle as you walk over the sand-dunes, is home to coastal skinks, and the fleshy fruit provide a ready food source. But there are other native critters that depend on the Muehlenbeckia vines.
The common copper butterfly or pepe para riki, (Lycaena salustius), lays its eggs amongst the vines. These give the embryonic eggs some protection from predators, and provide food for the emerging caterpillars. Some caterpillars develop normally into larvae then adult butterflies, but others spend months in diapause at the first larval stage, and are at risk of being parasitised by wasps so any protective cover is beneficial to them. The lengthy suspension of growth is presumably to provide a survival mechanism to some of the population should climatic conditions not be suitable at a particular period.
Copper butterflies are hard to miss as they flit along the coast displaying their bright orange and black wings. There are at least 9 species and probably more yet to be named.
There are 5 species of Muehlenbeckia which are suitable as host plants for the copper butterfly. The common Muehlenbeckia complexa is vigorous, but even more so is the larger-leaved vine, Muehlenbeckia australis, which climbs over forest margins. A tidy, diminutive species is Muehlenbeckia axillaris forming carpets along stream edges and on the cobbled floor of braided rivers. A rare 2m shrub, Muehlenbeckia astonii, occurs in eastern areas of central New Zealand. The fifth species, Muehlenbeckia ephidroides, is a nondescript grey mat-forming plant of boulder beaches where it blends amongst the greywacke and the bleached branches washed ashore along the high-tide line. All are suitable habitat for evolving copper butterflies.
Try the smaller Muehlenbeckia species as they are relatively simple in their needs and have a unique New Zealand look.