Nick Baker’s Bug Book

Let’s get this straight – anything with more than six legs is not an insect. Arachnids are a group of mini-beasts that includes spiders and a few other oddballs. They come in a variety of shapes and sizes but they all have two things in common: four pairs of walking legs and no antennae.

At times it seems the whole world is suffering from arachnophobia or what I call ‘Miss Muffet Syndrome’. Just mention the word ‘spider’, let alone reveal a living one, and someone will almost certainly fly out of the room in hysterics!

Although all spiders use venom to subdue their prey and a few can just about manage to sink a fang through human skin, there is no reason to fear any British spider.

Spiders come in many shapes and sizes: gangly ones, dumpy ones, fat ones and thin ones. Some are very hairy, others appear smooth as silk, some are sombre in colour and others are actually quite pretty!

There are spiders that hunt alone, spiders that spin elaborate traps, underwater spiders, surfing spiders, parachuting spiders, spiders that jump, spiders that steal from other spiders and even pirate spiders that murder their fellows. They are a truly versatile bunch.

With the naked eye you can see that a spider’s body is in two parts joined by a narrow waist called a pedicel. For a more thorough examination, you will need a hand lens and it will help to use a bug restrainer for some of the faster ones.

The front bit is a bit like the head and thorax of an insect combined. Its technical name is cephalothorax, which means ‘head chest’. The cephalothorax is the engine room and control centre of a spider. It contains a lot of the nervous system and muscles, the stomach and the venom glands, all encased in a box-like external skeleton, with a hard shield on top.

The eyes of most spiders are so simple that most cannot see very well at all. (Apart from some jumping spiders, which can see detail up to 30 cm away.) Some spiders definitely can use their eyes to detect mates and predators by seeing detail and movement. Some wolf spiders use light to navigate by and all spiders can at least detect differences in light and dark.

Most species have eight eyes arranged in two rows but there are always exceptions to the rules – some have six and some have only four. Others have a large growth with eyes placed directly on top of the spider’s head. The differences are very useful when identifying spiders.

The ‘mouth’ of a spider is a set of structures that process the unfortunate prey in stages.

The fangs – also called the chelicerae – are situated either side of the head. They come in two parts: you can see the bases below a spider’s eyes if you look at it head on but the sharp tip is often tucked away. These are the nearest thing these animals have to hands – not only are they used on prey, they can also pick things up, wind up silk, dig burrows and carry eggs around. Some of the tiny money spiders even produce noises by rubbing them together!

Venom is squeezed out of the muscular venom gland in the head region, and injected into the prey through a microscopic hole in the fang, a bit like a hypodermic needle. The venom paralyses the prey to stop it struggling and then it slowly dissolves the prey’s insides, creating a liquid lunch.

Spiders have a very muscular stomach attached to inside walls of the cephalothorax and they suck up this liquid, filtering it through several layers of hairs and bristles that stick out around the mouth.

Everybody knows spiders have eight legs, but when you count them you might think it looks as though they have ten. Sticking out either side of the head are palps, which look like legs. But besides being one segment shorter than a leg, they are definitely not used for walking. If you watch a spider for a while you will see it use the palps to tap things as it travels. A spider’s palps are super sensitive and are used to grab, feel and taste prey. They also play a big role in the sex lives of male spiders.

The next time you see a House Spider have a close look at its palps. If it is a male (and they usually are because it is the males that go ‘walkies’ looking for females), it will look as if it has boxing gloves on. These structures are used to inject sperm into the female. Some species also wave them about in courtship or threat displays.

Spiders’ hairy legs are not just to make them look scary. A bald spider would be a dead one as spiders need bristles for all manner of essential tasks. To a spider its hairs are camouflage, ears, nose, grippers, tasters, comb and hairbrush! There are many different kinds of bristles cut out for different kinds of work.

Some of the hairs that cover the body in a dense velvet give spiders their camouflage, patterns and sometimes groovy colours. The colours act to break up the spider’s outline and help them blend into their background.

It’s hair that enables spiders to crawl up the smooth surfaces of walls and take a stroll across the ceiling. Each foot has a device made from lots of special hairs, called scopula hairs (scopa means broom in Latin). Each one of these hairs looks just like a brush divided into hundreds of even smaller extensions like tiny bendy spades. Each ‘spade’ uses the surface tension of the microscopic film of water found on most objects – a bit like the effect when a coaster sticks to the bottom of a wet glass.

Even a spider with only a few of these hairs on its foot, such as a Crab Spider which has only 30, can achieve 160,000 separate grips on a surface. This is why species with even more scopula hairs than this can support more than ten times their own weight when resting on even the smoothest glass surface. Other hairs on the feet are sensitive to tastes and chemicals and on the legs there are hairs used to comb the silk and yet others are used as a brush to keep all the other hairs in good working order.

Spiders haven’t got ears but they can pick up vibrations and sound waves in the air which is pretty much what our ears do. Just about all the hairs and bristles scattered on their body have a nerve ending. These allow the spiders to feel their environment with their whole body all the time.

The larger hairs are mainly used as triggers to tell a spider that something is moving or not – watch how the spider reacts if you try tickling one of these hairs with a pin. The finer, feathery hairs (called trichobothria) are easily ‘blown’ by even a tiny vibration or breeze and can tell a spider where its next meal is coming from.

Some spiders have specialised hairs for specialised jobs. Water spiders rely on the hairs and bristles on their body to trap a layer of air in place, allowing them to breathe under water.

Wolf spiders can carry all their babies on their backs because their hairs are modified with a knob which acts a bit like a handle or grip for their young to hold on to.

Most of the time spiders are slow unless running from a predator or pouncing on prey, when of course speed is of the essence. They can’t keep their speed up for long though, because they do not have efficient lungs.

They have a special organ called a ‘book lung’ – it’s not easy to see but you may just make out a tiny pair of slits on the underside of the abdomen, near the waist. Air passes into the spider here and wafts over lots of thin plates that look like the pages of a book. From here oxygen passes to the blood and at the same time waste gases pass out.

More active spiders may also have a tiny hole in the body wall, called a spiracle, which leads to a network of fine tubes that take air from outside to the internal organs.

Walk through long grass in the summer and you may notice small spiders scatter from your path in huge numbers. Get down on your hands and knees and look at these spiders and you will notice a miracle in micro-mothering.

Most of these spiders will be wolf spiders, so called because they hunt like wolves. They use their big eyes to spot their prey and then they chase it down and pounce. They do not spin a web, and they don’t hunt in packs, although sometimes it may appear that way because there are so many of them.

One of the commonest is a species called Pardosa amentata. Like many of the wolf spiders it is various shades of brown with a beige stripe running down its back, perfect camouflage for a hunter.

Because these spiders do not have a web, the females carry their eggs around with them in a silken cocoon slung beneath the abdomen. You might see the off-white egg sac before you see the spider carrying it.

If you peer a little closer you will see females carrying a bundle of spiderlings on their backs. Wolf spiders are good mums and will carry their young for about a week, giving them a head start before they wander off into the grassy jungle on their own.

Now to the back end of the spider: its abdomen. You can think of it as a kind of living ‘water bomb’ – lots of bits of plumbing, a heart, breathing apparatus, sex organs, guts and the all-important silk glands all contained within a sloshy blood bath.

The size of the abdomen varies. It can be podgy, plump and tight or withered and shrivelled, big and round or slim and slender, all depending on what species, what sex the spider is and at what stage of its life-cycle it’s at.

Silk is the spiders’ multi-purpose secret weapon. They use it as a building material, safety line, trap, glue and parachute. Other invertebrates produce silk – caterpillars and caddisfly nymphs to name a couple – but none are as masterly in their use of it as spiders.

Imagine being able to produce a substance with which you could build a house, support many times your body weight, glue things together, catch your food and fly and at the end of the day you could roll it all up and recycle it! Sounds like the ideal super substance. The true silk masters, the orb web spinners, can produce up to eight different kinds of silk.

Silk comes out of the spider’s body close to tip of its bottom. If you look closely at some species you will see tiny little projections that the animal seems to wiggle and wave – these are spinnerets. If you were to zoom in with a very powerful microscope you would see six spinnerets with lots of little nozzles or spigots. It is out of these spigots that the silk flows.

Look on dry banks and especially walls with crumbly mortar and you will probably see tiny white burrows, reinforced with a dense weave of silk. Look for the almost invisible radiating threads arranged like the spokes of a bicycle wheel.

The spiders down these burrows spend the majority of their lives waiting in the security of the hole. The only way to tempt them out is to trick them into thinking you are dinner.

There are a couple of ways to do this. The first is handy if you happen to have a musician in the family as you’ll need a tuning fork.

Strike the tuning fork and gently touch the ‘trip’ wires surrounding the spider’s lair.

By doing this you are fooling the spider into thinking you are an insect and it will rush out from its hideout to attack.

If you have trouble getting a tuning fork, try a party blower with a piece of grass taped to the end. Unravel the tube, hold the grass against one of the threads and blow.

An alternative is simply tickling the web with a blade of grass, although this doesn’t always fool the spider.

The Nursery Web Spider is one of the nomads of the grass jungles of field edge and hedgerow. This female is carrying her egg sac with her, a sight common in mid-summer.

Silk starts off as a kind of protein soup within glands in the spider’s body. As the silk comes out of the spigot, a complicated and rather magical process occurs and the silk stretches and hardens.

Watch a spider descending from the ceiling on a line and see what it does with its legs. It has one leg on the line all the time, controlling its rate of descent by pulling the silk out of the spigots, a bit like someone abseiling controls their rope.

Think of a web and you probably have an image of the ‘classic’ orb web – those gorgeous wheel-like structures that are certainly the most elaborate of all the spiders’ craft. These may look pretty but its true function is more sinister: to snare unfortunate insects. There are nearly as many different types of web as there are different spiders, ranging from simple sheets and tangles of silk to full-blown masterpieces.

1: The spider has to span the gap. It does this by letting the silk drift on the breeze and by jumping or walking between the two points. Once the line is fixed and taut, the spider then crawls along its bridge, spinning a second stretchy loose silk strand. Having attached both ends, the spider then returns to the centre and pulls the second strand down to form the main skeleton.

2: More threads are added, to form the spokes of the web, anchoring it to the surrounding vegetation.

3: The spider then returns to the centre of the web and begins laying down the ‘real’ trap, the sticky stuff that actually catches the prey. Silk coated with a sticky liquid kind of protein is what makes up the spiral.

4: The web is finally complete, a perfect snare and work of art all in one – we are talking superb form and function here.

5: Depending on the species, the maker of the web will lie in wait, either in the centre of the web or secreted off to one side in a shelter or curled leaf. The spider keeps a foot or two on one of the radial silk spokes to detect the slightest vibration created by prey getting tangled.

This is a very distinctive take on the orb web theme, belonging to two species in the UK, the Wasp Spider, Argiope bruennichi and Cyclosa conica. Both spin webs with thick, silk, zigzag stitching worked into the centre. The stitching is known as a stabilimentum and nobody can really agree what it is for.

Many species line their burrows with a silk sock. Amourobius spiders make their distinctive funnels in walls, crevices and among the litter. Prey animals get their feet caught up in the matted web and remain stuck there.

The webs of spiders that belong to the group Zygiella look like they started well but the spinner did not bother to finish off one corner. Follow the strand that runs through this ‘window’ and it will lead you to the home owner, waiting for a bite.

This is the design classic, the orb web of the Garden Cross Spider, the perfect aerial snag, most obvious towards late summer and autumn when these spiders mature.

If you want to learn about everyday spider life there is no better teacher than the House Spider. Of all British spiders this is one of the biggest and it is easy to find, study and keep as a pet. A simple tank with a few twigs and some soil and a few flies bunged in regularly is all you need.

YOU WILL NEED:

plastic aquarium with lid • bark, twigs and soil

1: Put your arachnid in the plastic aquarium. These come complete with a lid, built in ventilation and a hatch, which makes feeding your spider easier. Put in a piece of interesting bark, soil and a few twigs. The spider will provide the rest of its abode.

2: A few flies or other small creepy-crawlies every week should provide your spider’s food and moisture, but if the place you are keeping your spider is warm then drip a little water in too. Now watch him spin a web before your eyes.

Keep a record of what your spider does, how often it eats and sheds its skin and you will soon get to know these amazing little house guests.

YOU WILL NEED:

• a coat hanger or bendable wire

Spider silk is the strongest natural material and is weight for weight, length for length stronger than steel. But those strands are so thin it’s hard to demonstrate this strength. However, if you collect enough webs you can get some idea of spider silk’s remarkable properties.

Take a small loop of stiff wire, bend it around so it has a ‘spoon’-like shape (a ring with a handle) and on one of those dewy, cold autumn mornings, try collecting a few webs by placing the wire loop behind the web and drawing it forward. The web should stick. Repeat this several times – try to choose those without residents! Soon you will have lined your ‘spoon’ with pure spider silk.

You can place weights on the collected silk and you will be surprised at how much weight even just a few webs can hold. You can even take a little ball of tin foil and bounce it on the silk you have collected – it shows how strong and stretchy spider silk is. If you have enough silk, you could play a small game of tennis with a friend!

YOU WILL NEED:

spray paint • newspaper • artist’s fixative or hair spray • coloured card • scissors

It sometimes seems a shame that those gorgeous orb webs that you find draped in the shrubbery or hanging in the hedgerow rarely last longer than a day. Being fragile and ephemeral is of course part of their attraction and from the spider’s point of view they are disposable and recyclable insect traps. However, it is possible to preserve these structures and even hang them on your own wall.

First of all, choose a still day and find a real beauty of a web. Make sure it is dry (no droplets of dew) and make sure its maker the spider isn’t in residence (check well in and around the edges of the web especially in curled up leaves) as it really won’t appreciate what comes next!

Take a can of spray paint – white or black is a good choice – and holding a sheet of newspaper behind the web to stop you getting paint all over the plants or bushes, spray the web evenly and lightly on both sides from a distance of about 40 cm. Get too close and you will blow a hole in your web. Leave it to dry for a while and repeat.

The next step is to make your web super sticky. You do this with artist’s fixative (available from art and crafts shops). This comes in spray cans like paint and in the same way you coloured your web with paint, spray both sides of the web. You can also use hair spray.

Before it dries, take a bit of card, big enough for your web to fit on and of a colour that contrasts with the colour you sprayed your web. This is the trickiest part of the whole operation; you need to line the card up perfectly with the web and push the card onto the silk so that it sticks in the right place first time. Once the web has touched the card you cannot change your mind without ending up in a messy tangle!

If you’ve done it right, you should have a perfect web on the card. Use scissors to cut the supporting strands and you can give it another coat of fixative to make sure it’s well held in place. You can now mount this spider’s original in a frame and hang it on your wall! You could measure all the strands of silk and work out how much silk was needed to make your web and even collect the orb webs made by different species of spider.

Believe it or not spiders can be found at sea and in the air – as high as 3,000 m! They form part of a strange world of aerial plankton that drifts around on air currents. Go out on a dewy autumn morning and you can see why their technique is known as ‘ballooning’. Just about any long grass will be laced with the dew laden strands of silk, not webs as such but seemingly single strands that link grass blade to grass blade. Investigate closely and you may find the culprits, lots of tiny money spiders, either spiderlings or tiny adults belonging to a family known as Linyphilids. If you collect one of these minuscule animals on the tip of your finger and gently blow on it you may persuade it to ‘balloon’ for you.

If you are lucky, the spider will raise itself up on tip toes and allow the breeze to pull out a thread of silk, which will snake up on the wind. When this develops enough lift to overcome the weight of the micro-spider, it lets go and drifts off.

Lift ivy that has grown against walls, look amongst ferns and thick vegetation, in dark corners of the shed and under windowsills and you are sure to turn up a gangly life form that when disturbed wobbles off in a manic random sprint that is seemingly better coordinated than its cotton fine legs should allow!

The Brazilian name for them, which I rather like, is giro mundo, which refers to their speed and agility. We know them as harvestmen, owing to their apparent arrival towards the end of summer. This is when they mature and are largest and hence more evident.

The technical name for the harvestman family is the Opiliones. We have something like 23 species in Britain but even after a leg count has revealed eight legs, it is a surprise to some to find that they are not spiders at all, although they are arachnids.

They differ from spiders, which they superficially resemble, by not having any poison glands, not being able to produce silk and by having their body parts fused together to form a single button-like body, suspended usually when active between the long vegetation-spanning legs. If you have any doubts about identification, look at the body: a harvestman is an all-in-one affair, no two halves here!

Harvestmen hang around in shady places where it is moist, under window-sills, behind ivy or up against the shed eaves – only emerging to feed by night.

		Harvestman Leiobunum rotundum With long lever-like legs and a button-like body, it’s easy to see why this common species has many other groovy names, like air crab.
		Pseudoscorpion Over 25 species of these little creatures – the biggest is only about 5 mm long – live in the UK. Completely harmless to us, they have no sting in their tail, but they do have pincers loaded with poison glands, to tackle their minute prey deep in the leaf litter and compost. Look for them by spreading out leaf litter on a white sheet and investigating with a magnifying lens.
		Sheep Tick You are most likely to encounter this parasite in the ears and around the head of your dog after it has been in long undergrowth. These creatures have complicated lifecycles and rely on the chance that a suitable host will pick them up, where they feed on blood. Deer and sheep are the usual hosts.
		Red Spider Mite The biggest of the mites and one I come across regularly sunning itself on a spring morning on the walls of my garden is the Red Spider Mite, which looks like a small bobble off your granny’s favourite curtains that has come to life.
		Harvestman Nemastoma bimaculatum Daddy short legs! Not all harvestmen are blessed in the limb department. This one is found among the leaf litter.