Spider classification

Spiders belong to the Order Araneae of the Class Arachnida and there are three sub orders, which are Mesothelae, Mygalomorphae and Aranemorphae. Within this Order and suborders there are 95 families.

Arachnida derives from the Greek word for the spider. The Arachnida is a group of animals that are distinguished from insects by having only two divisions of the body the Cephalothorax { the head and thorax untited and the abdomen. there are usually four pairs of walking legs on the thorax. { insects have three body divisions, the head, thorax and abdomen and they only have three pairs of walking legs}.

In the UK there are 650 species, which were once divided into two tribes known as Octonoculina {eight eyes} and the Senoculina {six eyes}.

The general appearance of spiders is well known but there are some characteristics worthy of our attention. The young, as for an example, are born perfectly formed and no larval or pupal stages occur, although they do go through several "moults" or changes of skin before they attain maturity.

They have been known to live for 3-4 years and the feamle produce several broods, however, in the majority of cases they may not long survive the laying of the eggs.

Studying spiders and their habits. Source Kaidan Wikipedia.


The make up of a spider

1--fangs- 2. venom gland. 3-brain 4- Pumping stomcach

5-Forward arota branch. 6- Digestive cecum 7--heart.

8-midgut. 9- malphigian tubels 10-cloacal chamber 11- rear aorta

12-spinneret 13-silk gland 14- trachea 15-ovar { female}

16- book lung 17-nerve cord 18- legs. 19- pedipalp.

General characteristics.

The eyes of spiders are simple not compound as in the case of insects. Most spiders have four pairs of eyes on the front area of the Cephalothorax arranged in patterns that vary from one family to another. These eyes when viewed under a microscope are bright and the colour can also be observed, some of them are ruby coloured.

Below the eyes and above the mouth are the falces { chelicerae } or fangs which contain poison and are lethal weapons.The fangs fold away into a groove when not in use in the manner of a jack knife.

By utilising these formidable weapons, they catch, hold and kill their prey. The poison is held in a gland at the base and emmited through a small opening at the point of the fang. The legs have seven joints and on the foot are two or more curved claws, sometimes plain, sometimes toothed like a comb.

At the end of the abdomen are the spinnerets, or organs of spinning they are present, depending on the species in two, three or four pairs. These contain many minute openings through which the silk passes as a sticky fluid which hardens immediately it comes into contact with the air. Spiders breathe air.

The spiders web is a beautiful snare. It is constructed by the spider, making in the first instance a rough four sided framework of irregular threads, which are anchored down. From the centre point the spider spins its radiating lines, all of which are double. Finally the spider weaves the spiral line from one radial to another until the task is completed. using a a magnifying glass {hand lense} one can observe that most of the web is covered with sticky globules, and, it is due to these that insects become trapped. The spiral lines of thread have to be renewed as the globules dry up in the air.

Dandelion plume caught up in a spiders web


Raindrops on a spiders web after heavy rain. It demonstrates the strength of the web

Image by Dal

General characteristics continued.

The house spider's snare is a gauzy sheet of fine lines of thread, none of them sticky, in which the insect is literally entangled.

Between June and October is the period most spiders lay their eggs {refers to the UK } and until the month of September or even the following spring they are covered with a cocoon of silk.

Webs of spiders may be encountered in bushes, grass land, tree trunks,walls, in fact all most anywhere both in dry and damp situations. The spider itself may be discovered by touching the web very gently, in the hope that the spider will dart out in anticipation of an insect. Alternatively, and this takes a little practice, you can trace the ' clue' line, which leads from the centre of the web to the spiders hiding place.

Spiders, courting and young spiderlings.

The courtship of spiders is worthy of note. The males do battle for the attention of the female. The victor will then pose before her in some grotesque attitudes. However, the females are not always easy to please and some species the male could well be killed and eaten before he has chance to mate, and another male will be chosen by her. It should be stated , however, that such action among spiders is much rarer than is generally supposed.

Yet, even the most fierce od females shows great parental care of both eggs and resulting young. The wolf spider for example carries her eggs in a round cocoon attached to her body until they hatch, and then carries her young around until they are old enough to move around independentl

Spiderlings and gossamer

Many young spiders travel by means of a sort of gossamer ' parachute'. In his book ' The British Nature Book' {1909} S.N.Sedgwick, explains this phenomena in the following way---" standing on tiptoe with the abdomen elevated, the young spider spins into the air, a silken thread that floats upwards. When this is sufficiently long the spider gives a slight jump into the air, and thus, is launched on its aerial voyage, to descend at last some distance, perhaps miles from its starting point. it is these floating threads which,whether floating or at last tangled in vegetation, are known as gossamer.

" When a spider ascends its thread, what does it do with the thread?.it does not climb it like a rope, leaving it dangling below. It can not eat it for it climbs to fast for such an operation { though on occasions it does}. The answer is that the spider rapidly winds up the thread upon its legs in a sort of skein as it ascends, thus it can rapidly payout for the purpose of descent, as it may be noticed when a spider ascending its rope, suddenly drops four to five inches instantaneously."

A review of some spider species and their habits.

Atypus, is a genus of purse web spiders of the Family Atypidae and the sub order Mygalomorphae. There are twenty nine species of which only three occur in Europe. they have six spinnerets.They are recognised by their large cephlothorax and fangs, which are reddish brown. Makes a tunnel in the ground lined with silk. All the Mygalomorphes catch their prey by hunting.

 Puirse web spider  copyright belongs to site member Ste Bond.

Spider genera continued.

Lycosidae-the wolf spiders { so called because in days gone by they were thought to hunt in packs-they don't}.The female protects her cocoon fiercely. Very rapid movement when darting on their prey. They have six spinnerets. They catch their prey by hunting. There are 2,300 species that occur throughout the world in 100 genera.

Dolomedes--is a genus of large spiders of the family Pisauridae { raft spiders} there are 100 species world wide. These spiders are semi-aquatic.

Salticus--The jumping spiders of the family Salticidae. There are 48 species world wide. S,scenicus, is a very common species {UK} .They are small about a quarter of an inch long. It is recognised by its zebra like markings along with its habit of stalking and leaping upon its prey. In doing so it secures itself, by fixing a silk thread from its starting point and drawing it out as it jumps.

Thomisus--is a genus of crab spiders from the family Thomisidae { flower crab spiders} of which there are 136 known species in the world. they are short and broad species with the first two pair of legs being very long. Sometimes found hunting on bushes, where it spins long thread lines to serve as tracks for pursuing its prey. Other species hide in flowers to await their prey.

Philodromus--is a genus of Philodromid of which there are 250 known species in the world. these are crab spiders. Some live on heaths where it nests, with one or two cocoons. Flat and white, may be found on a branch, amidst a cluster of leaves which have been drawn together. The female will savagely defend her eggs if attached.

Clubonia, a genus of large spiders of which there are 429 species kinown. The cell containing the cocoon is under a leaf or crevice. here the female stays, only emerging to sieze an insect. The interesting point about the cell is that it contains two chambers, one for males and one for females. The spiders prey largely on the eggs of other spider species.

Spider guarding her cocoon. She will stay with it till her spiderlings hatch out.


A remarkable British spider

Argyroneta. A.aquatica is one ot the most remarkable of British spiders. the male is larger than the female, which itself is very unusual among spiders. the abdomen is covered with hairs. These spiders are almost entirely aquatic. The fine hair of the abdomen is utilised to trap air bubbles, thus when the spider is emerged in water the spider appears to be surrounded by a silvery globe.

The female constructs her cell under water, attached to some aquatic vegetation, and, is shaped like a miniature thimble which she fills with air. Around it she produces extending threads, designed to entrap water insects. She is not entirely aquatic and will, on occasion, go on to land to nunt her prey. When prey is procured she will then convey it to her nest.

Her eggs are laid in the thimble like structure. The young hatch and like the adults are surrounded by air bubbles. During the winter they hibernate in cells beneath the water surface.

Argyroneta aquatica. Male on the left female right.

Courtesy of Baupi  CC BY-SA 3,0 License.

A study of spiders.

The study of spiders has advantages other than the intrinsic one, shared by few other branches of nature study. For an example, the study can be undertaken throughout the year. In cold winter months, spiders can be found in their natural habitat. many of the orb-weaving spiders, including the European garden spider, can be encountered in the evening when they appear either constructing a web or repairing one.

During day light hours many species of spider, ie, ground spider, jumping and wolf spiders hide under bark, or stones, or behind woodwork. Whilst other places that can be observed are decayed trees, old willows, wall coppicing, corners of sheds and out buildings, cellars and lofts, may all be home to a spider

Some interesting facts about British spiders  courtesy of Buglife conservation.

Spitting spiders spray gluey nets out of their jaws that stck insects particularly flies to the ground.

British spiders vary in size from the tiny money spiders through to the huge cardinal spiders. tegenaria parietina has a leg span of 10cm.

The heaviest spider in Britain is probably the four spot orbweaver, Araneus quadratus, at 25g.

The whelk shell jumper Psuedeuophrys obsoleta lives in sea shells on the Kent, Essex and Suffolk coats of England.

The Midas tree weaver Midia midas lives only in ancient forests in old hollow trees or birds nests.

The woodlouse spider Dysdera crocata eats woodlice and has extra long jaws with which to bite them.

The noble false widow Steatoda nobilis is found in Hampshire, the Isle fo Wight, Dorset and Cornwall, it is thought to have arrived in the UK from the Canary islands on imported produce.

The lady bird spider is very rare in the UK.

Image courtesy of Viridiflavus CC BY-SA 3.0 license.

Spiders under threat in the UK.

The lady bird spider, Eresus sandaliatus is extremely rare and found on just a couple of sites in Dorset {southern England} It is now so rare it is legally protected and may not be removed from the wild.

Fen raft spiders are very rare in the UK.

Distinguished jumping spider, Sittiaus distinguendus, is found on just two sites in the UK, one in Essex, one in Kent, on brown field sites

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UK BAP species.

UK BAP Species are animals and plants that have declines in their population/distribution of over 50% since 1995. As such they are added to the Red list of conservation concern. Many have species action plans {SAP} being implemented in an attempt to halt and eventually reverse these declines. Below are the spiders that occur in this unfortunate category.

{ SAP}=Species Action Plan.

Yellow striped bear spider --Arctosa fulvolineata.

Duffy's bell head spider-- Baryphyma dufffeyi

Serrated tongue spider-- Centromerus serratus

Rosser's sac spider--Clubonia rosseriae --An original UK BAP species, there is a SAP.

Small mesh weaver--Dictyna pusillia

Silky gallows spider--Dipoena inornata

Fen raft spider--Dolomedes plantarius-- an original BAP species , there is a SAP

Lady bird spider { see above } there is a SAP

Welch's money spider--Erigone welchii

Cotton's Amazon spider--Glyphesis cottonae.

Heath Grasper---Haplodrassus dalmatensis

Peus's long back spider--Mecopisthes peusi

Thin weblet---Meioneta mollis

Midas midas--Midas midas

Broad groove-head spider---Monocephalus castaneipes

Horrid ground weaver--Nothophantes horridus.

Swamp look out spider--Notioscopus sarcinatus

Southern Crablet--Ozyptila nigrita.Sand running spider--Philodromus fallax

Lichen running spider---Philodromus margaritatus

Whelk-shell jumper--Psuedeuophrys obsoleta, there is a SAP for this species

Triangle Hammock spider--Saaristoa firma

Cloud living spider--Semljicola caliginosus

Bend -bearing blunt-brow spider---Silometopus incurvatus

Sedge jumper--Sitticus caricis

Distinguished jumper--Sitticus distinguendus

Gentle groove head spider--Tapinocyba mitis

Small horned Walckenaer--Walckenaeria corniculan