This article was published in the Titirangi Tatler, February 2011

Putaputaweta - marbleleaf

In case you had not noticed, 2010 was the International Year of Biodiversity.
The United Nations declared 2010 to be a celebration of life on earth and of the value of biodiversity for our lives. The role of humans in the landscape is seldom defined as providing habitat for everything else, but that is what 2010 was all about. In case you missed it and want to redeem yourself there are opportunities aplenty in 2011.

This year is both the International Year of Forests and forty years since the Convention on Wetlands was signed on the shores of the Caspian Sea in the Iranian town of Ramsar.
International conventions may not have much bearing on what you plant in your garden but they can provide the guidelines for creating suitable habitat to increase biodiversity in your own backyard. With or without a wetland, a Carpodetus serratus will be a start towards the making of a habitat for many native insects and birds.

Putaputaweta is the sole NZ member of the Carpodetus genus, there being about 5 other species all in New Guinea. Growing into a small tree of 5 or 6 metres, it performs perfectly well in a normal garden, but in the wild it shows a preference for wetter conditions where there may be standing water for some months. It is an attractive tree, not too large for small gardens. Its curiously-mottled bronze leaves and zigzag branches create an elegant and graceful plant. In addition, the abundant white flowers of the putaputaweta attract other insects in spring and its black fruit attract birds in summer.

As a habitat, it is probably host tree of choice for the caterpillar of the puriri moth. Yes, the moth also chooses the puriri as a host but the poor caterpillar must work hard to chew its way into the tough timber of a puriri. Putaputaweta provides a softwood alternative that is obviously popular as there is seldom a tree to be found without the scars of caterpillars' tunnelling. Recent bore holes have a silken web woven across the tunnel mouth disguised with the sawdust-like wood fibre secreted by the resident caterpillar. Safely entombed inside the trunk, the caterpillar can stay there for years pupating and preparing to emerge as New Zealand's largest moth. All that effort for a few days of courtship and laying eggs before the adult moth dies.

But the now-open tunnel is not wasted. A second tenant moves in. This creature is so commonly found inside the tree that it shares its name, ‘weta', with the putaputaweta. Most likely it will be a male tree weta, often with his harem of up to 10 females. Don't be alarmed by its fierce appearance. Tree wetas are placid and normally prefer to be left alone. If disturbed and angered they can react aggressively by rasping their rear spiny legs against their abdomen to make a distinctive hissing sound. If cornered they can bite but generally do no lasting damage. Their nocturnal habit and omnivorous diet mean you may never see them as they clean up a lot of scraps and keep your backyard free of garbage.

So as you can see, lots of our unique biodiversity can be attracted to your garden merely by the presence of a graceful putaputaweta.