DoC

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.

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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.

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 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”.

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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.

Designs preserved in metal

Print blocks

From the Vaults is a regular Midweek feature in which a member of staff from the Whanganui Regional Museum discusses an item or exhibit from the museum’s vast collection. Front of house staff member Yoka van Dyk is a print maker – among other things – so it was appropriate she choose some Nancy Adams print blocks for this story.
The blocks were commissioned by the Department of Lands and Survey – the predecessor of DoC – in the 1980s and were made for illustrations in official publications about Egmont National Park, including a handbook and track pamphlets. They feature original art work by botanical artist Nancy M Adams.
Yoka saw them on display in the ‘new acquisitions’ section.  “They’re just exquisite little objects, just beautiful,” she says.
To accompany her story, Yoka brought along a burin, one of the tools that would have been used to make the print blocks. The burin is a fine chisel used for engraving designs on metal. “There are all different types,” says Yoka, “because you have different ones to make different lines. This point is very sharp with a sort of lozenge shape on the very end and it fits comfortably in your hand.” She demonstrated the use of the burin, keeping it low to remove a sliver of metal and show how varying depths of cut, using the wedge-shaped cutting edge, will produce different widths of line.
“These ones are very finely detailed and you have to be a very good drawer to be able to execute designs like this,” she says.
Both the skill of the engraver and the detailed designs of Nancy Adams are represented by the print blocks, which are made of brass, mounted on wood. Nancy Adams’ watercolours and drawings are widely known through reproduction in nearly 40 publications on native trees and shrubs, alpine plants, wild flowers and seaweeds that she has written and illustrated.
“Before, there were no books for the layman, really, only for botanical scientists, and with no pictures, so she jumped into that gap and started illustrating plants. And because she was a scientist as well, she could combine the two – her scientific side as well as her exquisite, articulate artistic side,: says Yoka.
Her father was an amateur horticulturalist, so Nancy  – born Jacqueline Nancy Mary Whittaker – grew up with Latin botanical names and a deep interest in plants. She joined the Dominion Museum in Wellington in 1959, eventually specialising in marine algae. She retired in 1987 as assistant curator of Botany and became an honorary research associate of the museum.
Quite a few of the print blocks are seaweed illustrations and each engraving is an intricate, detailed work of art. Engraving as a means of illustration was very common before the advent of photography and is still used for fine work.
“With drawing you really have to observe every minute detail, and interpret that. For her [Nancy], the real process was using the hand and eye,” says Yoka.
As well as working front-of-house at the museum, Yoka spends Mondays working at the Sarjeant Gallery. “I love working in the cultural hub of Wanganui,” she says.
Yoka came to New Zealand from Holland in 1987, intending to take a six-month break from her work as an artistic therapist. The country evidently appealed. She returned to her homeland in 2009, intending to live. She lasted 10 months and returned to New Zealand. An account of Yoka’s story and the nature of her work will feature in a future issue of Midweek.

 

Original article appeared in the Wanganui Midweek on 25th July 2012. Reproduced with permission from the publishers.