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What is an arachnid? Why are ours so special? Why do spiders build webs? How do some survive underwater? WHY DO SOME HARVESTMAN HAVE HUGE JAWS? How do some spiders cross continents? How can you look after arachnids in your own backyard? Award-winning science writer Simon Pollard and Te Papa arachnids expert Phil Sirvid answer these questions and more to reveal this incredible and unique world.
CMYK: 260mm x 220mm
Why is THAT spider dancing? the amazing
arachnids
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SIMON POLLARD AND PHIL SIRVID 28/06/21 4:02 PM
▶ A fly’s view of an
encounter with a New Zealand water spider.
What’s in This book? Part One
Welcome to our world 6
who are aotearoa’s amazing arachnids? 8 Part Three
How do we study and care for arachnids? 98
Part Two
Where do our arachnids live? 40 What does that word mean? Who wrote this book? Who helped make this book? What page is that on?
104 107 109 110
▲ The underside of a mygalomorph spider. Fangs line
▲ The underside of an araneomorph spider. At rest,
something solid, like the ground or the bark of a tree, beneath its feet. Mygalomorphs do not hang out in webs, not only because a web would not support their weight, but also because the way they use their fangs means they wouldn’t be able to strike at any prey stuck in the web. Some mygalomorphs, like the tunnelweb spider, however, do build webs on the ground. Araneomorphs have fangs which close like pincers, helping them catch prey while they are suspended in webs. It also means they can be very small – some araneomorphs have a body length of only a few millimetres. About 10 percent of the spiders found
in Aotearoa are mygalomorphs, while the other 90 percent are araneomorphs. Tarantulas, which are not found here, may be the most massive and usually the hairiest mygalomorphs, but even so, Aotearoa has some very impressive small and medium-sized mygalomorphs.
up down the middle and the spider has to raise the front half of the body to unfold them for use.
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fangs are held across the body and the spider can bite in almost any position.
Dining with the arachnids Nearly all arachnids are carnivores, which means they eat other animals. Some of them will also scavenge on the remains of dead animals, eat insect eggs and other spiders’ eggs, and drink nectar. Spiders have to turn their food into a sort of soup before they can swallow it.
▼ A female water spider
(see page 85) sucks up the insides of its prey.
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How Big is that ? y l l a e R , id n h c a Ar Garden wolf spider Anoteropsis hilaris body length: 7 mm
Black-headed flax jumping spider Trite planiceps body length: 11 mm
Avondale spider
Delena cancerides body length: 25 mm
Katipō
Latrodectus katipo body length: 8 mm
Daddy-longlegs spider
Flower spider
Diaea ambara body length: 5 mm
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Nursery web spider Dolomedes minor body length: 25 mm
Pholcus phalangioides body length: 7 mm
All spiders life-Size Garden orbweb spider Eriophora pustulosa body length: 11 mm
Square-ended crab spider
Sidymella angularis body length: 9 mm
Black tunnelweb spider Porrhothele antipodiana body length: 30 mm
False scorpion
Order Pseudoscorpiones body length: 5 mm
White-tailed spider Lampona murina body length: 16 mm
Shorter-legged harvestman
Nuncia sp. body length: 8 mm
Vagrant spider
Uliodon albopunctatus body length: 25 mm
Long-legged harvestman
Family Neopilionidae body length: 7 mm
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◀ A female little-
humped spider with wrapped prey. ▲ A close-up of the spinnerets of a tunnelweb spider.
The way spiders use a safety line of silk to stop them from hitting the ground really makes them the original bungee jumpers. be recycled and used to make more silk in the future. The way spiders use a safety line of silk to stop them from hitting the ground really makes them the original bungee jumpers. You may be wondering how a spider stops the silken line it is attached to from getting longer and longer as it falls. Near the spigot, the spider has a valve which can turn off the flow of silk. When it closes the valve, its safety line stops getting any longer. It’s very clever really. The silk of a safety line is only one strand, but the silk from glands used for wrapping prey is made of many strands. If you were wrapping up a tasty present, like a
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trapped fly, you would want a wide piece of wrapping paper or silk, not a single thread. Many species of spider also use silk to glide through the air. This is called ballooning, which is a bit confusing as they don’t use a balloon. Think of it as being more like paragliding. Young spiders climb off the ground onto something like a stalk of grass, so they can pick up a passing breeze. They point their backsides to the sky and release a line of silk. The wind then carries the spider and silk aloft, and off they go. Ballooning may carry the spider a short distance, but if they glide into large wind currents they can travel hundreds, if not
▼ An orbweb spider
pulls out a strand of silk from its spinnerets.
▲ A simulid fly trapped
by sticky glue droplets on the web of an orbweb spider.
▼ A female katipō
sits inside her web with her egg sac nearby.
▲ Katipō eggs
inside a protective cocoon of silk.
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▶ A cobweb spider
sucks the insides out of a fly. Next to her is a clutch of yellow eggs barely wrapped in silk.
▲ Mating tree
trapdoor spiders.
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How old is that arachnid? Most spiders live only for a couple of years, but some mygalomorphs like the trapdoor spider (see page 66) can live for well over twenty years. Some tarantulas live for more than thirty years.
Cambridgea) disguise their egg sacs with pieces of plant debris. The tailed forest spider (Arachnura feredayi ) has egg sacs that look like a chain of sausages hanging in the web. Some spiders are marvellous parents who care for and guard their spiderlings until they can look after themselves. Some mothers such as the garden wolf spider (Anoteropsis hilaris) carry their babies on their backs. Others like the Rangatira
spider (Dolomdes schauinslandi) keep their babies safe in a nursery. False scorpion mothers (see page 76) keep their babies safe by staying with them in a silken dome. Their silk comes from a structure in their chelicerae, rather than their rear end, as in spiders. They even provide food they make themselves for the nymphs after they have hatched. The silken domes also come in handy for staying safe from predators, especially when they are mating and moulting. Harvestmen do not produce silk, so they cannot wrap their eggs to protect them. Some just lay their eggs in soft soil and leave them to hatch and look after themselves. But one harvestman, a species of Karamea, is a stay-at-home daddy-longlegs dad who remains with the eggs under a rock or log as they hatch and develop.
▼ Sheet-web spiders (species of Cambridgea)
disguise their egg sacs with pieces of plant debris. ▶ A tailed forest spider’s chain-of-sausages egg sac.
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Eyelash mites Now it’s time to meet a couple of mighty arachnids that make you their home. That’s right, they live on you! To give you a clue as to where they live, one of them is commonly called the eyelash mite (various species of Demodex). They are too small to be seen without a microscope and are usually found living in the tube-like structures called follicles from which the hairs of our eyelashes and eyebrows grow. They feed on the dead skin cells and oils found in the follicles. Most mites are round, but eyelash mites are sausage-shaped and their eight legs and mouth are at one end of their body. They are the perfect shape to squeeze into
▲ Close-up of the microscopic,
sausage-shaped eyelash mite.
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Most mites are round, but eyelash mites are sausageshaped and their eight legs and mouth are at one end of their body. a tube-shaped follicle. While you may not like the idea of tiny arachnids living on your face, most people have them, and they rarely cause any problems. Scabies mites (Sarcoptes scabiei) are much more of a problem. They burrow into your skin and make you itch and develop rashes. They can spread from person to person easily, especially in overcrowded places. Fortunately, they can be treated with medicines.
▶ A scabies mite viewed
through a microscope.
◀ A female nursery web spider
guards her babies inside her tent-like web.
▼ A crowded nursery of
nursery web spider babies.
Spider kindergarten One spider builds a structure that most people in Aotearoa have seen. The nursery webs of the nursery web spider (Dolomedes minor) resemble odd-shaped white tents on the top of plants like gorse and broom. They are very common in grasslands and farmland, and sometimes large numbers are found close together, as if the spiders were meeting at a spider campsite. Within the nursery webs are round egg sacs, which the mother carries in her chelicerae before she seals them in her silken nursery. When the baby spiders emerge from the egg sac, they are protected from the weather and also from baby-spider-eaters
by the nursery web’s thick silk. You are only likely to see their mother at night, when she climbs up from the bottom of the plant and onto the nursery web to guard her babies from predators in the darkness. After they have moulted within the safety of their silken shelter, the young spiders leave the nursery. But how do they get out? If you look carefully, you can see that empty nursery webs are pitted with tiny holes – a tell-tale sign of how the spiderlings escaped. They use their fangs to bite through the silk, leaving their spider kindergarten for the big, wide world of spider adulthood.
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EARLY ARACHNOLOGY IN AOTEAROA
▲ Webs on Simon’s window.
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Formal scientific study of Aotearoa’s arachnids began in 1837, when the Frenchman Baron Charles Walckanaer described just ten species collected during an expedition a decade earlier. The first paper to be published about spiders in New Zealand was an 1857 article on the katipō’s venomous reputation. A British zoologist, Reverend Octavius Pickard-Cambridge, later suggested paying healthy young New Zealanders to be bitten to test just how venomous! Arthur Urquhart (1839–1919) was our most important early arachnologist. He described nearly 200 species and his spider collection is now at Canterbury Museum.
Simon’s love affair with spiders Hopefully this book will inspire you to study the arachnids you come across in your daily life. That’s the sort of thing I love to do, but then I really love spiders. When my wife Cynthia and I moved to our current home, around thirty grey house spiders (see page 55) came with us. They had been living in webs on the outside of two living-room windows, a prime spot for spiders like these. No other windows in the house attracted so many spiders. For around ten years, generations of these spiders had built their webs and we never removed them. As you can see in the photograph, it looked like a window from a haunted house – which we liked! When it was time to leave, I carefully removed each of the spiders individually from their webs and put them into small tubes. At our new place, they were released into what I hoped would be good environments for them to live. I thought it was unlikely that the people who were moving into our old home would want so many webs on a couple of windows. I was right. When I visited a few weeks later, both windows were totally free of webs. But luckily for the spiders, just like us, they had a new home.
Studying aliens in the forest A long time ago, I turned my interest in spiders into my job as a scientist. I became interested in studying male harvestmen with big jaws when I saw one for the first
▲ Ridiculous mouthparts.
time in rainforest on the West Coast of the South Island. I couldn’t believe such a tiny body could support such huge folded chelicerae. I wanted to know why males had evolved such ridiculous mouthparts (see page 68). Each year, I spent three to four weeks staying at a university field station close to the town of Harihari. I would go into thick forest to look for the males, which I often found in hanging moss. I would carefully put them on a small sheet, and with a special measuring tool, I would measure the size of their chelicerae and bodies. I would also check how many legs they had and whether they had mites attached to their bodies. Then I would very carefully put them back on the moss. One of the great things about studying animals in their own environment is that you see what they get up to. Once, I saw a male and a female together. The male had a dead fly, which he opened up with the
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WHY IS THAT SPIDER DANCING? THE AMAZING ARACHNIDS OF AOTEAROA Simon Pollard and Phil Sirvid RRP: $29.99 ISBN: 978-0-9951138-9-1 PUBLISHED: October 2021 PAGE EXTENT: 112 pages FORMAT: Paperback SIZE: 260 × 220 mm FOR MORE INFORMATION OR TO ORDER https://www.tepapa.govt.nz/about/te-papa-press/ childrens-titles/forthcoming-book-why-spider-dancingamazing-arachnids-aotearoa