Our five-part series with Auckland Museum's experts on our fascinating natural world concludes with this look at spiders with Virgil Evetts, director of the Children's Discovery Centre
Scorching sun, salt spray and the danger of being washed away twice a day make life on the beach challenging for the few hardy creatures that make this sandy environment their home.
The majority of animals living above the high-tide mark on the beach are arthropods insects such as kelp flies, midges, butterflies, bees, wasps, sand-hoppers and a number of different spiders.
Spiders everywhere fall into two basic types: web building spiders, the ones that use a web to catch their food; and hunting spiders, the ones that actively pursue their prey.
This article looks at three spiders you may find at the beach in New Zealand this summer. The infamous but very rare katipo spider, the rarely seen but very common nursery web spider, and the fast-moving hunter, the jumping spider.
All of these spiders are native to New Zealand, but have close relatives in many other parts of the world. Because spiders cannot fly (although some spiders are known to travel long distances as babies, suspended from tiny parachutes of silk), this suggests that they either arrived in New Zealand on floating rafts of vegetation and other debris from overseas or they already inhabited the land that is now New Zealand before it broke away from the great southern continent of Gondwana about 167 million years ago.
Many different spiders can be found in and around coastal environments. Spiders are best observed in the wild and, being mostly nocturnal, the best time to see most is at night. Take a torch and tread carefully. Spiders' eyes reflect light, which can make finding them quite easy.
The Nursery Web Spider
The nursery web spider is responsible for the distinctive web tents - which really are protective nurseries for baby spiders - commonly seen on various plants in the scrubland behind beaches, on farmland and even on the sides of open roads around much of New Zealand. While almost everyone has seen these, few people have ever seen their large and rather handsome spider-architects.
The nursery web spider has a leg span of about 50mm, looks furry rather than hairy and is yellowy-brown in colour with dark brown stripes running down both the cephalothorax [front part] and abdomen [back part].
The easiest way to find these spiders is to look for a nursery which is still in use. Old, abandoned nurseries are full of small holes where the baby spiders have chewed through the web and crawled away.
The best time to look for the adult spider is on warm, dry nights. The female spider will be sitting on or very near to her nursery. During they day she will usually be hiding nearby, but may rush out to investigate if the nursery is disturbed. They are very attentive mothers.
Nursery web spiders are quite large by New Zealand spider standards, and can inflict a painful although harmless bite, so handling them is not a good idea. Like all spiders, they do not come looking for trouble and far prefer flight to fight.
Trite bimaculosa and other species
Jumping spiders are among the commonest, or at least most often seen, spiders in New Zealand. In coastal environments these small, fast-moving spiders can be found mostly on the foreshore, among rocks, scrub and on cliff faces.
They certainly live up to their name too, using their excellent sight to spot prey, such as sand-hoppers and small native butterflies, before jumping on them.
There are a number of different species of jumping spiders in New Zealand, both native and introduced. Some are more at home in the bush, others at the beach and others seem happiest in suburban gardens.
Jumping spiders are not hard to keep in captivity - but they are quite hard to catch without causing them injury. Also, they are much more interesting to observe in the wild. Unlike many spiders, jumping spiders will, as long as you keep still, quite happily carry on hunting or eating in human presence. Jumping spiders are very unlikely to bite and they do not produce venom that is toxic to humans.
The katipo spider, with the distinctive red stripe running down its black abdomen is most famous for being New Zealand's only truly dangerous spider (to humans), however it is sadly also among our rarest.
This is largely due to habitat destruction and other human activities. Katipo is a highly specialised beach dweller and can only survive in the very fragile sand dune environment. Coastal housing developments, riding horses, quad bikes, even walking through sand dunes all contribute to dune collapse, which can wipe out whole populations of katipo overnight. More recently, competition from an introduced species of spider has further reduced katipo numbers.
The best way to help katipo numbers recover, and the best way to avoid being bitten by one, is to stay off the sand dunes or stick to official paths. The survival of this spider is just as important as the survival of any other native species.
The katipo is only found among the sand dunes of exposed beaches, building webs among spinifex grass and driftwood and feeding on whatever small flying insects they can catch. Despite their reputation, the one or two alleged deaths from katipo bites happened many years ago and are generally thought to be related to secondary infections or other complications. However, this is not a spider you should in any way attempt to find and you certainly shouldn't handle them. Katipo anti-venom is available, but will not save you from a stay in hospital. In the very unlikely event that you are bitten by a katipo, seek medical assistance immediately.
Anti-venom is species specific - so it's important to be sure that it was a katipo that bit you. Ideally you should take the offending spider, or whatever is left of it to hospital with you.
Virgil Evetts has been fascinated by the natural world since he can remember.
He particularly loves spiders and is delighted about the museum's addition to its live animal collection - a baby tarantula - which will be uncovered in Weird and Wonderful in a month or two.
"I love working at the museum and particularly in our discovery centres where I am lucky enough to see kids transfixed by our collections every day," he says.
* Illustrations from Powell's Native Animals of New Zealand, published by Auckland Museum.