Eriovixia gryffindori

Meet the spider that looks like a Hogwarts sorting-hat – Eriovixia gryffindori

By Dr. Alison Blyth | May 24, 2018

sorting hat spider

Eriovixia gryffindori is a small spider, just 6 mm long,discovered in India in 2015. Found in the Western Ghat mountains, Eriovixia gryffindori hit the news when scientist Javed Ahmed and his team decided to name it after Godric Gryffindor, the original owner of Hogwarts’s magical sorting hat. The inspiration behind the name was the tiny spider’s unusual shape, with a conical abdomen that looks just like a piece of magical head-gear.

The Erivixia gryffindori is the latest, and thanks to the Harry Potter connection, most famous of 21 species belonging to the genus Eriovixia. These orb-weaving spiders are found mainly in tropical Asia, with a few species restricted to Africa. The muggle species are nearly as unusual as their magical cousin. For example, the Orb-Web Spider from Thailand often flaunts a magnificent lemon yellow or flaming orange abdomen, while the Japanese species E. pseudocentrodes shares its Indian cousin’s hat-like shape, including a black version suitable for the darkest wizard. Why do these spiders look like this, and how many other unusually shaped spiders are lurking out there?

Orb Web Spider (Eriovixia sp.) found in Khao Yai National Park, Thailand.



What is a spider?

Scientists define a spider as an animal with eight legs, a body that is formed from two pieces (a head and an abdomen), which is able to spin silk out of its bottom for use in building a shelter or catching prey. Spiders breathe air and have fangs in their mouths to inject venom into their prey (and sometimes into unfortunate humans). They belong to the larger scientific class of arachnids, making them cousins to scorpions.

As of 2018, there are over 47,000 species of spider in the world, and with over 750 new types discovered in the last year. As spiders are small animals that often lurk in crevices and under rocks and leaves, it is extremely unlikely that science has yet counted them all.

The first spider

Spiders are not just incredibly numerous and diverse – they were also some of the first creatures to live on land. From the first primitive spider that crawled amongst the rocks during the Devonian period 380 million years ago to the advanced web-spinners of the Jurassic, who shared their forests with dinosaurs, spiders have been present through the evolution of much of life on Earth.

As a result, they have had the time to spread onto every continent, and into every habitat, from deep caves to baking deserts. They have evolved all sorts of adaptations to make their lives safer and their hunting techniques more effective. Looking like a hat is only one of them.

Weaving a web

The Eriovixia are orb web or orb weaver spiders, which means they spin classic wheel-shaped webs. A spider makes these by stringing out many radial spokes of non-sticky silk to attach the web to surrounding objects, and then adding strands of sticky silk between them to catch prey. Once their meal is stuck to the web, the spider can pounce down, stick in those venomous fangs, and wrap it up to keep for later.

orb-web-spiders
The classic wheel-shaped webs of orb-web spiders



Orb-weavers are tidy-minded animals. When they’ve finished with their web they eat it, so as not to waste the nutrients in the silk, then go and hide out in crevices or in the undergrowth. When they are ready for more food, they spin a fresh web in a new location.

Spiders evolved the ability to spin these aerial webs by the Cretaceous period (which started 145 million years ago). We know this through some very special fossils.

Amber is the resin that oozes out of certain trees from wounds in the bark. As this sticky substance slides down the plant, it covers anything in its path, including insects and spiders. The resin hardens with time, creating a time capsule of the animals inside.

That is what happened in one of the most remarkable fossils ever found. Sometime around 100 million years ago, an orb-weaving spider made its web on a tree in modern Myanmar. The web was a success, because into it blundered a parasitic wasp. However, before the spider could settle down to dinner, a glob of resin descended and entombed them, spider, wasp, web and all.

orb web spider
A 100 million-year-old fossil showing a spider attacking prey in its web. (Photo courtesy of Oregon State University)



Life in disguise

Spiders are small and soft-bodied (even the largest spider, the Goliath Birdeater from South America, is small compared to some predators), which means to survive and thrive over hundreds of millions of years, they have had to come up with some pretty cunning ways to avoid being eaten.

The shape of Eriovixia gryffindori is one result of this. Although nature didn’t set out to select for a Harry Potter reference, there is an evolutionary advantage to its looks. Eriovixia gryffindori lives in the Kans forestlands of the Karnataka region of India, amongst bushes and leaves. Its mottled brown coloring and pointy shape allow it to impersonate, not a wizard’s hat, but the tip of a dried-up leaf – unappealing to eaters of both spiders and vegetation.

Other Eriovixia take a similar approach. E. pseudocentrodes has been seen mimicking a thorn on plants, while E. laglaisei (or Lagalaise’s Garden Spider) looks more like a wart on a leaf.

Leaves, dirt, ants and poop

Mimicry is by no means restricted to the Eriovixia. A number of species have jumped on the bandwagon in an amazing variety of ways.

Following Eriovixia gryffindori’s lead in leaf impersonation is an undescribed species of spider from China. This spider-without-a-name, which is another type of orb weaver, was found by accident in 2016 in the Yunnan rainforest, and has gone the whole hog when it comes to what scientists call “leaf masquerade”. Not only is its greenish abdomen shaped like a leaf, coming to a long twisted point like a withered stem, but it even has markings that look like veins. It was only because Slovenian scientist Matjaž Kuntner caught sight of a strand of spider silk that this remarkable animal was discovered at all.

More down to earth is Paratropis tuxtlensis, a spider discovered in Mexico in 2014. This spider plays dress-up, using secretions to glue particles of dirt and dust all over its body. It can then blend in with the ground under its rock.

Some spider species are more creative. Impersonating ants is so common that it even has a name – “myrmecomorphy”.  Ants make for unpopular prey – they bite, they spray formic acid, and they can be really aggressive about it – so mimicking them to deter other animals from eating you is a smart strategy.

Cyclosa ginnaga, an orb weaver from south-east Asia has a different approach to being inedible – impersonating bird poop. The spider, which starts with the advantage of being silver, weaves a splotch of white silk into its web and decorates it with pieces of leaves to give variation in color and texture. Scientists have shown that viewed through a predatory wasp’s eyes, these areas of the web look identical to local bird droppings.

But the first prize among spiders for headline-grabbing fancy dress has to go to another Cyclosa species, this time from the Peruvian rainforest. This little spider has found the ultimate disguise – itself.

Using silk, pieces of leaves, and any other bits and bobs hanging around in its web, the spider builds a larger replica of itself, complete with abdomen and eight legs. The species, and certainly the behavior, is relatively new to science, so why it wants to do this is not yet fully understood, but the most likely explanation is that it aims to confuse predators into attacking the wrong “spider”.

Against that sort of behavior, masquerading as wizard’s sorting hat looks quite straight-forward!

Harry Potter and the art of scientific communication

Harry Potter Sorting-hat Spider

Eriovixia gryffindori is by no means the only animal to draw its name from the Hogwarts canon. A parasitic wasp now delights in the name Ampulex dementor after the soul-sucking demons, whilst a tiny crab from Guam is known to posterity as Harryplax severus, celebrating Severus Snape (the Harry in the name refers to the collector who discovered the genus).

How do you name a new species, and who decides if you can call a dinosaur after a school for wizards? Well, there are rules. The first scientific test, of course, is to prove that the species is new to science – no one wants animals ending up with six different names. Once that is done then a name has to be found that is original and appropriate (names are not allowed to be offensive).

Names also have to be arranged to fit the “binomial convention”, which means they must have a genus name (e.g. Eriovixia), and then a species name (e.g. gryffindori). Often the genus name will already exist (as was the case with Eriovixia gryffindori), and the lucky scientist only has to think of a species name.

Traditionally, scientific names were based on unique characteristics of an animal (another spider, P. octomaculatus is named for the eight (octo) spots on its back), its location, or for famous scientists in the field.

Names drawn from popular culture are a relatively new idea, and not universally popular. Some traditionalists suggest they’ll date badly – although much the same could be said for Victorian explorers few people have heard of today. However, there are good reasons for embedding popular culture in science.

Ahmed and his team described their choice of name as “an effort to draw attention to the fascinating, but often overlooked world of invertebrates, and their secret lives”. Meanwhile, A. dementor was named by museum visitors. In both cases, the idea was to get the public interested in science and conservation. A quick google search of Eriovixia gryffindori vs the similarly shaped Eriovixia pseudocentrodes shows how successful this approach can be.

For spiders, and many other invertebrates, public attention is important. Endangered cute furry mammals may be the poster species for conservation, but the welfare of less glamorous animals is equally vital. Spiders are hunters and predators who keep many of our less loved pest species under control. A world without spiders is a world in which flies, cockroaches, and many agricultural pests run riot.

Unfortunately, spiders, despite their numbers and the new species being discovered every year, are being affected by human activity. As we build more houses, use more sprays, and change how we manage our farmland, the natural habitat for many spiders is altered. Some, like house spiders, adapt to life in their new environments, but others, such as Australia’s Cascade Funnel-Web, go extinct.

In this context, maybe we should be celebrating Eriovixia gryffindori and its discoverers mode widely. They have not only added to our scientific knowledge with a beautiful and bizarre animal but with a canny piece of naming, they have put one of Earth’s most under-rated animals on the front page.

This article was written by Dr. Alison Blyth, a scientist and freelance writer specializing in earth and environmental sciences.



References:

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