Natural History

Cave Crabs of Bali

As a museum curator, I’ve done field work in lots of places, but this was the first time I’d had to wear a purple sash.

The sash and sarong were hired for 5,000 rupiah (about 50c) from a shop by the main road on the island of Nusa Penida, near Bali, Indonesia. I was about to venture into a cave to look for endangered crabs, but because the cave is also a popular Hindu temple you have to be properly attired.

1. Entrance Giri Putri

 You are warned when entering Giri Putri cave that it is a sacred place.

The Giri Putri temple used to be just a smallish hole on a hillside; you have to crouch, clamber, and shuffle to enter it, before the ceiling rises and you’re in one of several large caves. Today, there are steps, buildings, white-clad priests praying, and a visitor’s book.

Back in 1993 Australian biologist Tony Whitten explored Giri Putri, and was struck by the number of crabs scuttling about on the cave floor. He collected some, and they turned out to be not one, but two new species, dubbed Karstarma emdi and K. balicum. Freshwater crabs like these can be found in several cave systems in south-east Asia. They have long legs for feeling their way about in total darkness. Isolation and time leads to speciation, and the two species in Giri Putri seem to be found nowhere else but this small cave.

4. Hindu Temple at Giri Putri

Giri Putri is a working Hindu temple, with worshippers present at all hours, leaving food offerings and coexisting with insects and bats.

Unfortunately, they’re under threat. Giri Putri is now a busy temple with artificial lighting everywhere, large fans to keep the air moving, lots of concrete and tiled floor and rows of benches and altars. Whitten noted that in every visit he made there were fewer crabs, and in the hour I spent searching with a headlamp in the dark corners of the cave I didn’t see any at all. I asked one priest if the crabs were there. He told me “sometimes”. The International Union for Conservation of Nature is pushing for better monitoring of the crab population, and the temple authorities seem keen to work to minimise human impact, so here’s hoping.

There’s plenty of other life in Giri Putri, though. I kept disturbing bats which zipped here in there in silence, sometimes an inch from my face, reminding me that I didn’t get a rabies vaccination before coming to Bali. The walls of the cave were crawling with invertebrates, including large Periplaneta cockroaches, camel crickets that looked just like the cave wētā back in New Zealand and good-sized whipscorpions.

2. Cockroach

The cave was full of large winged cockroaches in the genus Periplaneta.

Back home, I uploaded the photos I’d taken with my phone to NatureWatch, and asked Mark Harvey at the Western Australian Museum what he thought. Mark identified them as tailless whipscorpions in the family Phrynidae, probably the genus Phrynus. This was interesting, because almost all species of Phrynus are found in the New World, through Mexico and Central America. The sole exception is a species Mark himself named and described, Phrynus exsul from the island of Flores, Indonesia, thousands of kilometres away from its closest relatives.

3. Whipscorpion

Whipscorpions are also known as whipspiders. They are arachnids, but are neither scorpions nor spiders.

Only one problem: Bali is 400 km away from Flores. So either these whipscorpions are Phrynus exsul and a new record far west of where they were first observed, or they’re an undescribed species of Phrynus.

Whipscorpions are not especially inconspicuous. Giri Putri is right by the main road, and a popular tourist destination. Nusa Penida is a short ferry ride from Bali, which has millions of tourists a year. And it seems that in over 20 years nobody has thought to collect one of these critters, take it to an expert, and find out if it’s an undescribed species or not. This is the plight of the tropics in miniature: stuffed full of biodiversity which is disappearing faster than we can discover and put names to.

 

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

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Bees, harvestmen, wētā and more take the stage at the Entomology Conference

Recently the War Memorial Centre hosted the annual New Zealand Entomological Society conference, and researchers from all over the country congregated to share their discoveries and find out what was happening in the world of bugs.

2. Australian resin bee

An Australian resin bee Megachile ustulata. Photo: MPI, PHEL, Milen Marinov

One of the talks was very relevant to Whanganui residents. In January, a Springvale couple discovered an odd-looking bee when it stung one of them. Realising it was unusual they forwarded the corpse to the Ministry for Primary Industries. James Haw of MPI explained it was identified as a species of Australian resin bee, Megachile ustulata, never before recorded in New Zealand. MPI searched the neighbourhood for more bees but came up empty-handed. In Australia Megachile ustulata is a solitary insect that makes its home in cracks and burrows. It especially likes the hollow ends of bamboo garden stakes. It is not clear if this was a one-off incursion, or if these bees have taken up residence in Whanganui. If you’re a keen amateur naturalist, keep your eyes open for resin bees when spring arrives. Feel free to bring possible specimens to the Museum (in sealed containers, please).

4. Tree weta Brodifacoum

Tree weta feeding on Brodifacoum

One of the more intriguing talks was by Adele Parli, a Masters student at the University of Otago, working on Wellington tree wētā (Hemideina crassidens). The Wellington species is the more aggressive of the two tree wētā we get in the Whanganui area. Adele was quantifying their aggressiveness with a measure known as the “poke test”; how many times do you need to poke the wētā before it flips its lid and begins to thrash and bite? The answer for the Wellington tree wētā was generally “once”. Adele was poking wētā to test whether their behaviour changes after feeding on the poison brodifacoum. Brodificoum is commonly used for rat and mouse control in the bush and around buildings, and is the rat poison anyone can buy at the supermarket without a permit. (It’s much less humane than 1080 and takes longer to break down in the environment, but you don’t see people protesting brodifacoum outside supermarkets.) Wētā love to eat brodifacoum bait pellets, and it doesn’t kill them, but Adele suspects it may be changing their behaviour, such as how often they emerge to feed, how far they travel, and how aggressive they are.

3. Daddy long legs

A common household daddy-long-legs Pholcus phalangoides. Photo: Olaf Leillinger CC-BY-SA

As well as talks on insects, there were presentations on spiders, which are more or less an honorary insect at these events. Anne Wignall at Massey University Albany had been studying a common house spider, the daddy-long-legs Pholcus phalangoides. These are territorial, staking out one corner of a ceiling and repelling intruders. Anne was curious about whether these spiders could recognize each other; something called the “dear enemy” effect in vertebrates, where animals are more aggressive to complete strangers than rivals they’ve already encountered. Sure enough, when spiders were allowed to become familiar with each other, their territorial battles, while no less frequent, became less violent. It’s remarkable to think that a creature with such a tiny brain can remember its opponents and assess the risk of fighting.

The conference finished with Bugs in the Pub in Frank eatery. Three entomologists gave short talks on beetles, insect weaponry, and whether we should eat more bugs, and invited questions from the audience. Afterwards, beers in hand, pubgoers chatted with the scientists and looked at a selection of live insects they’d brought along – a fitting end to a grand three-day conversation on the wonders of the insect world.

 

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

Stick Insects

Stick insects are often overlooked, and that’s the way they like it.

New Zealand is home to a wide variety of stick insects, from the horrid stick insect (Argosarchus horridus) with a body as long as your hand, to spiky creatures smaller than your little finger. Most species of stick insects are found in the tropics, so it’s peculiar for a cool-temperate country like us to have so many, even a mountain stick insect (Mimarchus tarsatus) that lives in South Island tussock that’s covered by snow all winter.

1. prickly stick insect

Prickly stick insect (Acanthoxyla prasina).  Photograph: Alan Gilchrist.

Although they’re relatively common, stick insects excel in hiding. Our New Zealand species are flightless and defenceless. If discovered, they will sway gently like a twig in the breeze, or drop comatose to the ground, where can lay immobile for up to half an hour before reviving and climbing a tree again. The best way to find them is by beating. Hold a white sheet or umbrella under a tree or shrub and hit the branches sharply with a stick and down they’ll drop. Over the last few months the Whanganui Regional Museum has been doing that on field trips around Whanganui and the Manawatū, and we now have a half dozen stick insects of different species, sizes and colours in captivity.

Stick insects are easy to keep. They only need a regular supply of green leaves (pohutukawa seems to be a favourite) and an occasional spray with a plant mister. They’re happy to be handled, and are a great “gateway insect” for children who might be nervous about handling a creepy-crawly, as they’re completely harmless. They spend most of their time slowly munching on leaves and laying eggs.

2. stick insect cage

Stick insects live happily in a cage as long as it’s not too hot and dry, and there’s a constant supply of fresh leaves. Photograph: Whanganui Regional Museum.

It’s possible to breed stick insects even if you only have one, because some of the most common species, the spiky stick insects (Acanthoxyla), are parthenogenetic. This means that no males are needed, with mothers laying eggs from which hatch only daughters. In fact, until this year, no males had ever been seen. Then one was found, in England of all places. The species had been introduced to England in the 1920s and is doing well. Males seem to be very rare mutants, not required for reproduction.

Because some stick insect species have just one sex and others have both, their genetics are very interesting to entomologists. Studying their DNA has also revealed unknown species hiding in plain sight. One of the new species was recently given the scientific name rakauwhakanekeneke, te reo Māori for “the stick that walks”.

3. stick insect eggs

If kept in a damp dish, but not allowed to go mouldy, stick insect eggs will hatch after a few months into tiny versions of the adults. Photograph: Whanganui Reigonal Museum.

The stick insects in captivity in the Museum have been growing steadily, and we’ve collected dozens of eggs, which are currently incubating. The hatchlings will be released back into the bush. Unfortunately, stick insects have a short life expectancy. They hatch in spring, reach full size in a few months, and usually don’t survive the winter. When ours die, we’ll preserve the bodies and put them on display in a new insect exhibition ready for when the Museum re-opens in October. Visitors will be confronted by a case full of sticks and invited to work out how many of them are insects.

 

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

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

Whanganui River Mouth – Te Kai Hau ā Kupe

Where a river meets the sea is a place of great fascination to people all over the world. It’s usually a place of great abundance for fishing as well as gathering whatever interesting wrack gets washed down the river and cast up onto the shore. If the river is large enough it becomes an entrance for shipping or boating, with all the consequent dangers associated with channels, rips and sand-bars.

The Whanganui River entrance has been shaped and changed by major human intervention from its original form. When we at look at old photographs or paintings of the river-mouth, what we see is very different from what is there today.

The building of channel-protecting moles on either side of the river entrance completely transformed, not only the river mouth, but also the coastal area to the west. Interrupting the longshore current that flows from west to south east causes the suspended sand to gradually accumulate against the obstruction. This has created expansive sand-dunes at Castlecliff and has moved the shoreline steadily seawards.

 

1. Castlecliff photo

 Whanganui River Mouth, Castlecliff Beach; Frank Denton, 20th century.  Ref: 1802.1016

One early image of the river mouth is a photograph of Castlecliff Beach by well-known Whanganui photographer Frank Denton. You can see beach visitors enjoying a stroll on the sand. The beach stretches around a natural curve at the river mouth and the sea-swell washes into the river. Ladies lift the hems of their long dresses over the wet sand while children play and paddle in the shallows at the edge of the river. In the far distance a line of surf marks the edge of the sea.

A set of three small watercolour paintings by itinerant artist Christopher Aubrey show the river mouth prior to the construction of the moles. Although the paintings are faded and damaged by long exposure to light and damp, all the details are still visible. Each painting depicts the curve of the river towards the entrance at different times of day. Looking closely, we can see that in 1894 there was a significant sandbar, indicated by a thick line of surf across the across the river entrance. The line of surf across the river-mouth ends at a sand-spit that stretches out from a large cliff on the Castlecliff bank of the river.

Along the river margin stretched a beach with a gentle sloping edge, forming a useful pathway for riding horses or for herding a flock of sheep to the freezing works in the background. The Wanganui Freezing Works were established in 1891 to process the farm animals produced in the surrounding rural areas and freeze them for transport out of the region by ship. The paintings also show ships berthed in the river adjacent to the freezing works, a large ship anchored just offshore and a small vessel crossing the sandbar.

Despite the better shipping channel created by the construction of the moles, the difficulty of negotiating the sand-bar and surf have resulted in a number of shipwrecks over the years, including the Port Bowen which, in 1939, ran aground on a sand-bank, fully laden with a cargo of mutton and lamb from Whanganui destined for export to England.

With the proposed development of Whanganui Port it will be interesting to notice and record further changes to the landscape of the Whanganui River mouth and see how future sea-going vessels manage the difficulties of “crossing the bar”.

 

Margie Beautrais is the Educator at Whanganui Regional Museum

The Mysterious Adzebill

New Zealand was once home to many flightless birds. Some, like the moa, are well-known, but others, like our flightless ducks, geese, and owlet-nightjar, are familiar mostly to palaeontologists. One bird that deserves to be better known is the mysterious adzebill.

1. Adzebill Martinson

A North Island adzebill (Aptornis otidiformis) eyes up a tuatara in a 2005 painting by Paul Martinson.
Photo: Te Papa / CC-BY-NC-ND

There were two species of adzebills, Aptornis otidiformis in the North Island and Aptornis defossor in the South. Both were huge. When their bones were first discovered, they were mistaken for a small moa. Fully-grown birds would have weighed perhaps 20 kg, larger than a swan or pelican.

Adzebills had massive heads with heavy down-curved beaks. The beaks tapered to a point, and Dr Richard Holdaway, who coined the name “adzebill”, once confessed to me that “pick-bill” would have been more accurate. The robust vertebrae in their neck would have anchored strong muscles and allowed them to deliver a powerful blow.

These birds also had massive feet, with strong tendons, that would have made them good at digging. For some time biologists debated what they ate. Did they dig up roots, pluck leaves or break apart rotten logs? Their beak wasn’t hooked like a bird of prey.

A technique called stable isotope analysis which lets us analyse animals from the composition of bone – you are what you eat – revealed that adzebills were carnivores. We can imagine them tearing open trees for huhu grubs, plucking lizards or baby birds off the forest floor, digging up giant earthworms, and excavating tuatara, or even nesting seabirds, out of their burrows.

A second mystery was what adzebills were, exactly. They didn’t resemble rails like the weka or takahē, and for some time were put in their very own family. Some ornithologists thought their closest relative was the flightless kagu of New Caledonia. Others thought it belonged with chicken-like South American birds called trumpeters. The debate continued fruitlessly for decades.

Alex Boast is a PhD candidate at the University of Auckland, working on ancient DNA. Improved techniques now allow us to recover and examine fragments of DNA from bones and eggshell of extinct birds, not enough for Jurassic Park cloning, but enough to construct a family tree and determine their nearest relatives. Alex analysed adzebill DNA and compared them to numerous other birds, and the results suggest that adzebills are not kagus, or trumpeters. They are flufftails.

2. Flufftail Keugelmans

The white-spotted flufftail (Sarothrura pulchra), painted by John Keulemans in 1894. This delicate little bird seems to be the adzebill’s closest living relative.
Ref: Wikimedia Commons

Flufftails (nine species in the genus Sarothrura) are secretive ground-dwelling birds about the size of a starling, rusty brown and spotted. They do indeed have fluffy tails. What’s unusual is that flufftails are all found in Africa, and on the island of Madagascar, nowhere near New Zealand.

Africa and New Zealand were once connected as part of the supercontinent Gondwana of course, and fossils tell us that adzebills have been here for millions of years, plenty of time for their ancestors to get here and evolve into a giant flightless predator. Intriguingly, the kiwi seems to have done the same thing. Its closest relative is another African species, the elephant bird of Madagascar. The difference is, while one flightless bird survived the arrival of human beings and became the symbol of New Zealand, the other was wiped out. The not-so-mysterious adzebill is now mostly forgotten.

 

Dr Mike Dickison is curator of natural history at the Whanganui Regional Museum.

Moths and the night

Spring is here, and the moths are emerging. Overwintering as a pupa, they emerge when the temperatures rise, to mate and lay eggs so their caterpillars can spend summer and autumn feeding and growing. A month ago, a light trap at Gordon Park would attract just one or two moths, but now, after an hour, the white sheet is covered with moths large and small, wasps that parasitise moths, flies, beetles and other nocturnal life. New Zealand has over 1,700 species of native moths, many barely known or still undescribed, and Robert Hoare at Landcare Research is the only full-time researcher working on them – his plate is pretty full.

2. light trap

Light Trap: Using LEDs in the blue and ultraviolet parts of the spectrum shining on a white sheet attracts nocturnal insects, which confuse it with the moon—the only bright light they’ve evolved to deal with. Photo: WRM.

While waiting at a light trap, being savaged by mosquitoes, you’ll occasionally hear a loud rustling and flapping as a huge pūriri moth (Aenetus virescens) or pepetuna, blunders into the sheet. Adult pūriri moths have beautiful mottled green wings, but they have no mouthparts and don’t feed, living on stored fat for the few days it takes them to find a mate and reproduce. In contrast to their brief adulthood their caterpillars, called mokoroa, live for years in holes bored into tree trunks; wētā will often move into the vacated tunnels. Once very common in North Island, pūriri moths are now only seen around native bush. In times past, swarms would emerge and fly into houses, extinguishing lamps and candles.

1. puriri

Pūriri moths emerge on damp nights in September and October to mate, lay thousands of eggs and die. Photo: WRM.

The decline in moth numbers is something that’s been noticeable, even in my lifetime. When I was a child, long drives at night left the windshield plastered with insects, but hardly ever so today. True, cars are more aerodynamic now, but the decline is certainly real, at least in Europe where it’s been carefully measured. Scientists, managing annual light trapping in Germany since 1989, have measured real declines in the numbers of nocturnal insects, down on an average of 45%, or 80% in some areas. There’s been no funding for this sort of long-term monitoring in New Zealand, so we have to rely on anecdotes about windscreens.

3. forest looper

Also known as the conifer flash (Pseudocoremia leucelaea), this moth is common in native bush in spring. Its caterpillars feed on tōtara and miro leaves.  Photo: WRM.

This insect decline has multiple causes: deforestation of course, the switch to intensive agriculture reducing the diversity of habitats in our farmland and the widespread use of pesticides. Systemic pesticides like neonicotinoids are restricted in Europe but widely used in New Zealand, and most discussion of their impact is around their effects on honeybees, not our thousands of native species.

4. cranefly

There are over 600 species of craneflies in New Zealand. Sometimes mistaken for a gigantic mosquito, they are harmless.  Photo: WRM.

Even artificial lighting might be a problem. Everywhere, including Whanganui, old high-pressure sodium street lighting is being replaced with modern LEDs, which are brighter and far more energy efficient, saving councils millions of dollars annually in electricity costs. The problem is that sodium lights were orange, whereas LEDs shine in the blue end of the spectrum, like those in my fancy new German light trap. Blue lights are far more visible and confusing to insects. In the name of energy efficiency, we’re busily lining our streets with thousands of high-powered insect traps, without much thought about the effects on nocturnal pollinators like moths.

Human beings have transformed the night, replacing the moon and stars with so much artificial light that we’ve forgotten what darkness is. When I lead night walks at Bushy Park we stop and do a simple exercise of turning off all our torches. Some of the children in the group are then in complete darkness for the first time in their lives. For many of the creatures of the bush, the night is their habitat, the place they can’t be seen by predators. They evolved in a world that had darkness, and in just a few hundred years we’ve driven that away.

 

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

Giraffe Weevils

In January this year the Museum helped run a night-spotting Whanganui Summer Programme field trip to Bushy Park. The participants were lucky enough to see, up-close, two long skinny insects that had been found by DOC’s Scotty Moore under a rotten log. They were giraffe weevils, New Zealand’s longest beetle.

1

A male giraffe weevil (Lasiorhynchus barbicornis) found by Scotty Moore at Bushy Park
Photo: Whanganui Regional Museum

The giraffe weevil’s Latin name, Lasiorhynchus barbicornis, means “hairy-nose with a bearded horn”. Its Māori name is pepeke nguturoa, or long-beaked beetle. (By the way, nguturoa is another Māori name for kiwi). They’re also called tūwhaipapa, after the god of newly-made waka, because their nose resembles a canoe prow. All these names refer to the male, who has a snout as long as the rest of his body with a fringe of hairs underneath.

Male and female giraffe weevils look very different, and were named as two different species when the specimens collected by Sir Joseph Banks on Captain James Cook’s first voyage were studied back in Europe. Female giraffe weevils are tiny compared to males, and have a shorter snout which they use to drill an egg-laying hole into dead trees. Their eggs hatch into grubs which eat fungus inside rotting wood for two years, finally pupating and digging their way out of the tree as adult weevils in summer. Peak emergence time is February, so right now is your best opportunity to see adult giraffe weevils in the wild, as they only live for a few weeks before mating and dying.

2

 Male giraffe weevil guarding a small female, who is busy digging a hole for her egg
Photo: Christina Painting / CC-BY-SA

An adult male giraffe weevil’s primary concern is finding a female, and they use their enormously long noses to fight other males by biting and wrestling, trying to dislodge their opponents from the tree trunk. When they find a mate they literally stand over her while she lays an egg, driving off all challengers. Some much smaller males employ a different reproductive strategy: while the big macho males are distracted by fighting and posturing, these little males will sneak in and mate with the female under their rival’s enormous nose. Research by biologist Chrissie Painting at Auckland University revealed that both these tactics were roughly equally successful at fathering offspring, which is why we see such a range of body sizes in male giraffe weevils. It’s like a field experiment in evolution: if one strategy were more successful, natural selection would favour it, and eventually male giraffe weevils would have all evolved a similar body size.

Chrissie was able to find several dying karaka trees in Matuku Reserve near Auckland where she could watch males battle and sneak, and observe their life cycle. She used tiny dots of coloured nail polish to mark the different males so she could tell them apart, and filmed them tossing each other off trees. Giraffe weevils are a useful study animal for observing evolution in action, because they’re active in the daytime (unlike many beetles) and easy to observe. After having to work long nights studying native harvestmen, she describes the weevils as “little angels”.

3

Female giraffe weevil, showing her much smaller snout, with antennae halfway along it, allowing her to chew nest holes; male antennae are near the tip of the snout
Photo: Christina Painting / CC-BY-SA

If you want to see real-life giraffe weevils for yourself, you could venture into lowland native bush between October and March, look on the trunks of rotten trees, and, if you’re lucky, see two long-nosed insects jousting.

 

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

Seashore Critters

The beach may be a nice place to visit, but you wouldn’t want to live there. Windy, hot, dry, barren and occasionally flooded by seawater, it’s a hostile environment for small animals. And yet there are some species that manage to make the beach their home. I spent a day at Mōwhanau recently with children from Brunswick School, turning over driftwood and logs and looking for interesting critters.

1. hopper

A common beach sandhopper (Bellorchestia quoyana), when examined closely, reveals its crustacean nature.

Photo: Crispychipp / Wikimedia Commons CC-BY-SA

Sandhoppers are the most abundant denizen of the beach. Under every piece of driftwood or seaweed is a multitude, which spring away or scurry down burrows when disturbed. These little creatures, properly known as amphipods, are actually crustaceans, not insects. They are cousins to crabs, crayfish and even the slaters in your garden. Like all crustaceans, they breathe through gills which they have to keep moist. Most of the roughly 10,000 species live in the sea, but amphipods can be found in any damp environment. Some Southern Hemisphere hoppers even live far from the coast in forest leaf litter.

2. log

A log, like this one found on Mōwhanau Beach, is like a tiny oasis, providing shelter and food for a whole community of invertebrates
Photo: Whanganui Regional Museum

 

On the beach amphipods burrow down to damp sand during the day and come out at night to feed on anything the tide has washed up. Close up, they resemble tiny humpbacked shrimps, ranging in colour from dark grey to pinkish-orange, and have powerful hind legs for jumping. Sandhoppers are an important part of the beach ecosystem, not just as food for larger animals, but as scavengers that break down seaweed and carry those nutrients as deep as 30 cm into the sand.

Another creature found under beach logs is the native seashore earwig (Anisolabis littorea). These are flightless, and much larger than the introduced European earwigs in your garden. Their Māori name, matā, is also the word for obsidian – black volcanic glass – because they’re similarly shiny and black.

Seashore earwigs are omnivores, feeding on seaweed or catching amphipods with their nippers. Unlike most insects, they take good care of their young; after mating, the female drives off the male and guards her clutch of eggs and helpless babies. Once the baby earwigs get large enough to fend for themselves, all bets are off. They can flee the nest, eat each other, or eat their mum (and she’ll happily snack on them if they try). Female matā have long straight nippers while males have curved asymmetrical ones.

3. earwig

The native seashore earwig or matā (Anisolabis littorea) is a beautiful glossy black creature found under beach debris all around Aotearoa
Photo: Lisa Bennett / NatureWatchNZ CC-BY-NC, with permission

Although they look fearsome, curving their pincers over their back like a scorpion, I’ve handled earwigs for years and never been nipped. The kids from Brunswick School were initially cautious, but when I showed them how you can gently let a big coastal earwig crawl from hand to hand, they all wanted to try.

The “ooh yuck!” response when presented with a creepy-crawly is not innate in children, but learned from their parents, peers and authority figures. There are native invertebrate species going extinct right now. Voters don’t care because bugs are “yucky”. Museums like Te Papa and Puke Ariki are putting on insect exhibitions to help fight this perception. If we adults are frightened of harmless little insects, it’s not the insect’s fault. We need to get over our irrational fears, model good behaviour for kids, and, on our next visit the beach, turn over some logs with them and see what we find.

 

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