Spectacular Longhorns

If people are asked to think of “an animal”, they almost always name a mammal, sometimes a bird or a fish, maybe a reptile. But all of these animals are vertebrates, with backbones, and most animals, by far, are not vertebrates. There are nearly 400,000 species of beetles alone, five times as many as all the vertebrates put together.

Part of the Museum’s redeveloped exhibitions will be a display of beetles of the Whanganui area, and one of the families of beetle we will be showcasing is the longhorns.

1. Variegated longhorn

One of New Zealand’s largest and most colourful longhorn beetles, the variegated longhorn (Coptomma variegatum) larva burrows into native trees like kōwhai and tawa. It is also known as the tawa beetle. Photo: Whanganui Regional Museum.

There are almost 200 species of longhorn beetles in New Zealand, many of them large and distinctive. They are generally unmistakable, having antennae that are almost as long as their narrow bodies. The larvae of longhorns feed on wood, dead or alive, which they can digest with the help of fungus that lives in their digestive system. Longhorn larvae live for years inside branches or logs before finally emerging as an adult beetle. The adult longhorn is usually short-lived. Its only job is to mate and lay eggs.

New Zealand’s largest beetle is a longhorn, the huhu (Prionoplus reticularis). At this time of year, these large clumsy beetles often fly inside, attracted or confused by artificial lights. Huhu can give a painful nip if handled, but surprisingly they don’t eat as adults, and only live for a couple of weeks, spending all their time looking for a mate.

2.Huhu grubs

Our largest beetle is the huhu (Prionoplus reticularis). Its finger-sized grubs live for years in rotting logs, and were a valuable food, raw or cooked, for Māori. Photo: Charlotte Simmonds CC-BY.

Some species of native longhorn beetles have become pests. The lemon tree borer attacks not just native trees but fruit trees, grapes, and ornamental deciduous trees. Its larva can ringbark and kill entire branches while burrowing. The two-toothed longhorn usually tunnels into fallen logs, but is happy to inhabit firewood or stacked drying timber. It can cause real structural damage, making tunnels much larger than the tiny holes associated with furniture borer (which is in an entirely different beetle family).

3. Blosyropus spinosus

The spiny longhorn (Blosyropus spinosus) is only slightly smaller than the huhu, but is much less common. This one was found at Bushy Park. You can see the paired spines on head and thorax from which this rare flightless beetle takes its name. Photo: Tom Miles / Zoomology.

Most of our native longhorns, however, are not pests; they concentrate on breaking down and recycling rotten wood in the bush. Many are large attractive beetles, and some can even hiss or squeak when disturbed. While on a Museum moth survey at Bushy Park, we came across the rare spiny longhorn (Blosyropus spinosus), New Zealand’s second largest longhorn species. A docile flightless beetle with paired spikes on its back, it is widespread but rarely seen. The National Arthropod Collection in Auckland, with 6.5 million specimens, contained only 22 spiny longhorns from the entire country, dating back to 1915. To know this species is surviving in Bushy Park is a testimony to the intensive rat and mouse control that’s been happening there. Conservation is about more than just vertebrates.

Dr Mike Dickison is Curator of Natural History at the Whanganui Regional Museum.



Insects of Java

5. Antheraea larissa

There are many species of silk moths in Asia: this one, Antheraea larissa, doesn’t even have an English name. Its caterpillars only live on the endangered forest tree Shorea glauca.

I recently spent nearly three weeks in Indonesia, mostly looking for tropical insects. In New Zealand we’re proud of our beautiful forests and amazing birds, but even a short time in Java drove home to me just how impoverished our flora and fauna are in comparison to the tropics.

Indonesia is the world’s fourth most populous country. Two hundred and sixty million people live there, 141 million in Java alone, an island smaller than the South Island. Even in a densely populated and developed landscape, there were still national parks and botanic gardens housing enormous biodiversity.

4. Milionia fulgida

Not all moths come out at night. Some, like this beautiful iridescent Milionia fulgida, pollinate flowers during the day.

We stayed in the Botanic Gardens of the town of Cibodas in the mountains south of Jakarta. The Gardens had guest houses for tourists and they left the outside lights on all night, for security reasons. Every morning all we needed to do was to stroll around the building to see extraordinary numbers of colourful moths and beetles that had been attracted to the lights overnight.

Each day we photographed about 15 species we hadn’t seen before; each morning would bring a new harvest, showing almost no overlap with the diversity of the night before. After a week of spotting a dozen new species every day without even trying, we realised we were barely scratching the surface of the biological richness of the tropics.

1. Grey Pansy

The grey pansy (Junonia atlites) is found throughout Southeast Asia; it was common in the Bogor Botanical Gardens.

New Zealand has a well-supported conservation movement, and DOC does its best to preserve our forests and endangered wildlife. We learn the names of our native birds, and every bookshop has shelves of coffee table books about kiwi and kākāpō as well as field guides to birds, insects and trees.

In Indonesia conservation operates on a shoestring. The national parks are full of litter. Poaching of endangered bird species is rampant. The bookshops have no field guides, just racks of publications about agriculture and fish farming. Huge swaths of untouched rain forest are being cut down for palm oil plantations – the same forests our shining cuckoos migrate to each winter.

3. Atlas beetle

Named after Atlas, who supported the world on his back, males of the giant Chalcosoma atlas beetle fight with each other over potential mates, using their enormous horns.

Most visitors to Indonesia holiday in Bali, but a better choice might be supporting ecotourism in Sumatra or Sulawesi where your money goes directly to preserving rain forest. New Zealand has thousands of threatened insect species that most people neither know nor care about, but our species are in safer hands than Indonesia’s. It sounds like heresy, but donating money to conservation projects in the tropics may do far more good for the world’s biodiversity than spending it here.


2. Hawk moth

Sphinx moths or hawk moths can hover like hummingbirds, and have long coiled tongues for drinking from tubular flowers. There are hundreds of species in Asia, and just one in New Zealand.

Dr Mike Dickison is Curator of Natural History at the Whanganui Regional Museum