Posterior

Small tubercle above the last pair of spinnerets which closes the anus

The body of the spider is divided into two major divisions: an anterior part (prosoma) and a posterior part (opisthosoma) which are connected by a narrow stalk (pedicel). The extremities of the prosoma are (from anterior to posterior): chelicerae, pedipalps and 4 legs. The mouth opening is laterally bordered by the gnathocoxae, anteriorly by the normally soft skinned labrum and posteriorly by the sclerotised labium. The lateral areas of the prosoma are soft (thus not or only slightly sclerotised), whereas the dorsal cover (carapace, tergum) and the ventral plate (sternum) are sclerotised. The "head" part of the prosoma bears the eyes. The most important organs in the prosoma are 1 pair of poison glands, the brain (nervous system), esophagus and the sucking stomach, as well as the endosternite and the muscles. The opisthosoma bears on the anterior part of ventral side the epigastric furrow with the genital opening and the spiracles, posteriorly normally 3 pairs of spinnerets. Organs within the opisthosoma: the tube-shaped heart, ventrally the respiratory organs (book lung, tracheae) and the spinning glands. Furthermore are within the opisthosoma the testes or ovaries, respectively, the strongly segmented midgut and hindgut. The hairs on the body of the spider are sensory organs that response to mechanical or chemical stimulus

A sclerotised infolding of the cuticula that provides an attachment for muscles. An important apodeme is situated under the fovea

Excrescence, process. The various apophyses of the male palp play an important role during copulation. They can provide a secure coupling with the female's epigyne or vulva. They also act as an "internal" locking mechanism for the palp itself, so the individual parts of the bulbus can be fixed in an optimal position.

Class of 8-legged invertebrate animals; for example the orders Araneae (spiders), Scorpiones (scorpions) and mites (Acari) belong to this class. At present there are approx. 80.000 species known worldwide, however the effective number of species is probably much higher

Phylum Arthropoda: e.g. the classes Insecta (insects), Crustacea (crustaceans), Myriapoda (millipedes) and Arachnida (arachnids) belong to this phylum. Over ¾ of all known species are arthropods. The >1 million species currently described are only a fraction of effectively existing species

Mostly relating to a vestibule of the vulva or the book lungs

The voluntary separation of an extremity. Nearly all spiders can autotomise their legs. Autotomy is usually used when a leg of the spider is snatched by a predator or when an extremity cannot be freed during moulting. The site where a leg is autotomised lies usually between the coxa and the trochanter. A closing mechanism prevents leaking of the hemolymph after the leg has been detached. Autotomised legs can be replaced at the next moult, but they are considerably smaller than before. The normal leg size can be reached after further moultings

First segment of the chelicera, mostly armed with teeth, bearing the fang

Habitat preference (see threats and habitat)

Anterior respiration organ of most spiders located anteriolaterally of the epigastric furrow; the book lung consists of thin lamellae arranged like the leaves of a book. The opening is situated at the ventral side of opisthosoma. In dwarf-forms the book lung can be converted to tracheae

Book lung

Hair-like formation of the cuticle. The term is usually used in determination keys for stronger and conspicuous, spine-like bristles on legs and palps

All female spiders exhibit brood care. In the simplest case, they protect the eggs, i.e., constructing a cocoon. The total amount of eggs inside a cocoon can vary from 100 up to 1000. The cocoon can be attached to a suitable place. Some spiders carry the cocoon until the spiderlings hatch (e.g. Lycosidae und Pisauridae, Scytodidae, Pholcidae) , thus they can provide optimal conditions for the development of the embryos. Many mothers tolerate the young spiders in their webs for some time, others (Lycosidae) carry the spiderlings on their body for some time. Only some spiders feed their spiderlings after hatching (e.g. Coelotes). In some Theridiidae species, the mother feed the spiderlings mouth-to-mouth with pre-digested, regurgitated food mash (regurgitation feeding), also known in Eresidae. In the latter case, the spiderlings feed on their dead mother

Male copulatory organ on last segment of pedipalp; in entelegyne spiders, the bulbus consists of several flexible sclerites and membranous hematodocha in between; in haplogyne spiders, the bulbus is more simply developed, mostly uniformly globular or pear-shaped. See also cymbium

Organ that consists of one or two rows of bent bristles located dorsally on metatarsus IV. Only in cribellate spiders; used for combing out the silk from the cribellum

Dorsal shield covering the surface of prosoma; named more accurately as "tergum"

Anterior body part; see also prosoma

The most anterior pair of extremities of prosoma in arachnids, consisting of a basal segment and a fang

Two distal margins of the basal cheliceral segment, mostly armed with teeth; the fang is situated between these two margins in resting state

Principal component of the cuticula; a nitrogenous polysaccharide

Backwardly directed, elongated process of median part of epigynal scapus; can be merged with parts of the epigyne, so that this "clavus sensu lato" bearing the copulatory openings

Area between eyefield and anterior margin of the carapace

Egg-case; A wrapping for the eggs, consisting of special silk produced by the female. The shape of the cocoon is sometimes species-specific. The often thick and coloured silk layers protect the eggs to a certain amount against evaporation, fungal infection, egg predators and parasitoids). The finished cocoon is normally attached to a suitable place, sometimes also carried by the female (Lycosidae, Pisauridae, Scytodidae, Pholcidae). See also brood care

Rudiment of the most anterior pair of spinnerets formed in embryonic development; its shape is mostly like a integumental lobe provided with bristles (not in all species visible or lacking completely)

Part of the embolic division, mostly serving as protection and guidance for the embolus

The male charges his bulbus with sperm before or during courtship. First, he spins a special sperm web and puts a drop of sperm on it. Then, he dips his palps into the sperm drop and the sperm is up taken. During copulation, the hematodochae (which are completely or partly reduced in haplogyne spiders) are inflated, so the sclerites of the bulbus are fixed in optimal position to each other and to the female genital organs. The sperm is transferred from the spermophor of bulbus through the embolus into the spermatheca of the female by increasing the hemolymph pressure and/or by displacement with glandular secretion. This procedure can last some seconds or up to some hours, depending on species. After the copulation, the female feed on the exhausted male (in some Araneidae, Theridiidae, etc.). Fertilization of the eggs takes place just before the eggs are deposited, often a long time after copulation

Mating

External pore of the entrance duct in the epigyne of female spiders

Courtship can be defined as a certain behaviour of males (females as an exception) of a species which is signalling the willingness for mating to the other sex. Furthermore, this behaviour allows the females to recognise the male of the same species and the females can make some sort of evaluation of the quality of the male. Male spiders have often to avoid to be confused for prey. Thus, the courtship can also "calm" the female. The courtship behaviour of males is very various: many web building spiders court a female by vibrating the web of the female in a species-specific manner. Other spiders (e.g. many Theridiidae) produce acoustic signals with stridulatory organs, whilst others "dance" or showing waving movements. By doing so, they also display conspicuously coloured body parts. The males of the Lycosidae court with highly specific drumming patterns; the substrate can be caused to vibrate by pitching the legs, the palps and the opisthosoma onto the ground. The males of Pisaura court with a bridal gift: an insect wrapped in silk, on which the female feeds. Some morphological structures indicate chemical courtship signals. If the courtship succeed, the female takes up the mating position. Copulations aborted by females (e.g. in Pholcidae) indicate that during copulation "courtship signals", in a broader sense, also play an important role. Presumably, such signals provide information about the genetic quality of the mating partner

First segment of the leg or palp; attached to the pleura

Catching threads produced by the cribellum. The very thin "catching wool" (diameter ca. 0.00001 mm) coats the more stronger axial threads. Prey is effectively entangled in this "wool", moreover, the cribellate silk has some adhesive properties

Spiders with a cribellum and a calamistrum

A spinning plate derived from the first pair of spinnerets; only in cribellate spiders; this organ can produce up to 50.000 single threads. This "catching wool" is produced with the help of the calamistrum and is supported by a thicker axial thread in the web

Tarsus of male palp; covers the bulbus dorsally

Food uptake

There is often the need for an epigynal dissection, in order to reliably identify a species. Therefore, a cut around the epigyne is needed. After this step, the epigyne with the inner vulva can be safely detached. Adherent tissue is carefully removed and the detached epigyne is put into clove oil or in an embedding medium which brightens the preparation (Svan, Berlese, Hoyer's). After a short time, the sclerotised structures of the vulva are visible and can be studied under the microscope. KOH or lactic acid cannot be recommended, normally the aforementioned procedure is sufficient. After examination, the detached epigyne have to be put into a micro glass tube and stored together with the specimen. The procedure is the same for haplogyne spiders, although more attention has to be paid, because an epigyne is missing and the vulva is often delicate and poorly visible from the outside

Dissected epigyne

Distant from centre or origin; see also proximal

Area where a species occurs and reproduces. It may be compact (continuous) or not (disjunct). The area of a species is not constant, since species still may settle new areas within the postglacial colonization process. Additional dynamics are created by current anthropogenic processes such as modern climate change and landscape change.

The distribution map of a species as given here per country or larger region bases primarily on data in Fauna Europaea (www.faunaeur.org). Additions are mentioned in the reference section.

Faced opposite to the mouth (the back or upper surface); see also ventral

Cocoon

Distal part of bulbus, consisting of the embolus and mostly several additional sclerites

Sperm transferring organ of male bulbus; contains the opening of the spermophor which is situated inside the bulbus

Inner skeletal element inside the prosoma of all spiders, formed by connective-tissue; serves as an attachment of several important muscles

Predatory insects (e.g. carabids, ants, kissing bugs) regularly prey on spiders. Although, other spiders are also important enemies, because many free hunting species feed on spiders ("cannibalism"). Pirate spiders (Mimetidae), for example, are specialised in preying on spiders. Among vertebrates toads, lizards and birds feed on spiders. Beside these predators, parasitoids are also important enemies. Also carnivorous plants, e.g. Drosera-Species (sundew) in bogs, catch wandering spiders

Spiders with a epigyne and vulva with two pairs of ducts

Connecting duct between copulatory opening and spermatheca of female vulva in entelegyne spiders; see also fertilisation duct

Transverse furrow on opisthosoma; entrance to the reproductive organs; the spiracles of the book lung are mostly situated lateral to the furrow

Sclerotised external plate covering the female reproductive opening of female; with the copulatory opening for the embolus; only in entelegyne spiders

Europe is biogeographically defined as western part of Eurasia. It does not include Canary Islands and other Atlantic islands close to Africa. The southern border of Europe is defined by the Mediterranean Sea. We include the Asian part of Turkey, Cyprus and the Caucasus states. In the east the border is indicated by Ural River and Ural Mountains.

The extraintestinal digestion of the spiders and the subsequent filtering of the food mash are the reason why there is only a few amount of excretory products. The most important excretory organ is a pair of Malpighian tubules. These originate from the border between midgut and hindgut in the opisthosoma. The excrement is passed over the stercoral pocket to the anus. Excrement of spider mainly consists of guanine. In the prosoma of "primitive" spiders lie two pair of coxal glands, which are reduced to the anterior pair in most spiders. They open to the outside at the coxa of the walking legs and release a fluid only during feeding. Presumably, the coxal glands play an important role in ion and water balance. Furthermore, some gut cells and the nephrocytes in the hemolymph have excretory functions

External rigid parts that serve as muscle attachments and support. The cuticula serves as exoskeleton in arthropods

Digestion occurring outside the intestinal tract; spiders sucking a pre-digested mash; digestive fluid from the intestinal tract is pouring on prey, so that its soft parts are dissolved (prey)

limbs; paired and originally segmented appendages. In spiders these are chelicerae, pedipalps and 4 pairs of legs; further modified extremities on opisthosoma (e.g. spinnerets)

Part of head region bordered by the eyes

Normally, spiders have four pairs of eyes. According to their position, they are referred to as anterior and posterior median eyes (AME, PME) and as anterior and posterior lateral eyes (ALE, PLE). In some groups of spiders (e.g. Segestriidae, Dysderidae, Oonopidae, Scytodidae) the AME are reduced, so there are only six eyes. All eyes are ocelli (or so-called primitive eyes): beneath the cuticular lens lies a cellular vitreous body and the visual cells. A light-reflecting layer of crystalline deposits, the so-called tapetum, is characteristic for the ALE, PME and PLE of many spiders. Presumably, the tapetum allows seeing at night or in dim light. There is still a lack of knowledge about the performance of the visual sense in spiders. Generally, the eyes of the spiders are surely less efficient than those of vertebrates. It is known that Agelenidae and Lycosidae can perceive polarised light and use it for orientation. Some groups of spiders have especially complex eyes (e.g. the AME of free hunting jumping spiders); that indicates a highly developed visual sense (like e.g. the active "scanning" of objects, perception of UV light and a high resolution)

Claw-like distal segment of the chelicera

Third segment of legs and palps

Duct with narrow lumen leading from spermatheca to uterus externus in the vulva of female entelegyne spiders; see also entrance duct

Oak leaf shaped dorsal pattern on the opisthosoma; often with deposition of guanine, an excretion product (see excretion)

Anterior margin of the carapace

Dorsal, mostly longitudinal depression on carapace (often an attachment for muscles)

Coxa of the palp; belonging to the mouth parts

Crystalline metabolic product of spiders; deposited in specialised cells under the cuticle and appears externally as white colour pattern (folium). See also excretion

Spiders are virtually found in all terrestrial habitats. Besides some unspecialised generalists (ubiquists), we know many species with highly specific preferences for some habitats. To what extend these specific preferences for some habitats in the nature match the actual requirements of a species is a current problem in research - presumably, some species are only displaced to extreme habitats by other species. These species aren't restricted to a certain habitat, in fact they only tolerate the conditions much better than other species. Beside competition, several other factors play a role in the choice of a habitat: the structural components, availability of prey, microclimatic conditions (temperature, humidity, shadowing, etc.). The effective habitat of a species is often realised at a small scale only. Important habitats in a forest are therefore the various soil layers, herb layer, as well as the shrub and tree layer (trunk, bark, treetops); even these narrowly defined areas aren't completely colonised by a species, but only where they find specific microclimatic conditions or other important circumstances. The current habitat of a species can rather be seen as a more or less dynamic arrangement of factors than a locally clearly defined area. This perspective can explain migrations of some species due to weather conditions or the occurring of a species in very different habitats depending on geographical position. There are examples of species which migrate from southern regions to Central Europe. They can occur in dense vegetation or even in forests in Mediterranean region, but in Central Europe they can only survive in very warm, open and vegetation-poor south-exposed slopes. Special cases are species which occur in buildings (synanthropic) or in ant nests (myrmecophilous). Only one European species, Argyroneta aquatica, can permanently live beneath the water surface

Spiders without an epigyne, only with one duct in the vulva

Soft areas of the bulbus, inflatable when hemolymph pressure is increased; connects the sclerites of bulbus among each other, connects also cymbium and bulbus

The bluish oxygen carrying pigment of the arthropods; binds the oxygen within the hemolymph (correspond to the haemoglobin of vertebrates)

Body fluid of the arthropods; from a functional point of view a mixture of blood and lymph fluid (name!)

Epigastric furrow

Book lung

A median sclerite of bulbus, separated from tegulum

Casting off the old cuticle. Because of the rigid cuticle, spiders - like all other arthropods - have to moult from time to time, otherwise growth isn't possible. Normally, a spider passes through 5-10 moults to reach the adult stage. During the last moulting intervals the sexual dimorphism becomes apparent and after the final moult, the sexual organs are completely developed. Moultings after reaching the adult stage can only be seen in orthognathous as well as in few labidognathous spiders (Eresidae). First of all a new thin and strongly folded cuticle is formed under the old cuticle. During this process, the new cuticular sense organs (sensory hairs, slit sense organs, tarsal organs) are formed. A fluid provided with enzymes is secreted into the gap between new and old cuticle. The enzymes dissolve the inner parts of the old cuticle. The dissolved components are largely resorbed, so there is only little material lost in the moulting process. Due to an increase of the hemolymph pressure, the old cuticle is ruptured laterally at prosoma. The carapace is lifted off and the extremities are extracted afterwards, and then, finally, the opisthosoma. Also the organs with chitinous cuticle are moulted, like fore- and hindgut, the book lungs and the tracheae

Posterior body part, in spiders originally consisting of 12 segments (body structure)

An organismn that has to spend a certain time of his life attached or within a (mostly larger) host organism in order to find optimal conditions for metabolism and/or reproduction at the expense of the host. Unlike parasites, parasitoids kill their hosts. Parasitoids of spiders are found among the hymenopterans (Hymenoptera). Pompilid wasps, but also some mud dobers (Sphecidae) paralyse spiders by their sting and the egg is laid on the spider's abdomen (the spider is still living). The hatched wasp larva is feeding on the living tissue until the spider succumbs. There are numerous egg parasitoids in the wasp family Ichneumonidae. They deposit their eggs in the spider's egg sac. Such egg parasitoids could already be understood true predators. Furthermore, there are also egg parasites among the flies (Diptera, e.g. the families Chloropidae, Sarcophagidae) and among the neuropteran (Neuroptera) the larvae of mantidfly (Mantispidae)

Palp

Annual appearance of species, distinct developmental stages or physiological processes. For spiders, here the appearance of fertile (adult) individuals is give per month.

Food

Retrolateral paracymbium found in pholcids

Eyes

Situated on the front side of an extremity. See also retrolateral

Spermatheca

Most of the spiders possess one pair of book lungs consisting of stacks of lamellae like pages of a book. These lamellae are double-layered and filled with air, thus hollow. Small chitinous columns prevent collapse of the narrow air pockets. The distance between the lamellae, where the hemolymph circulates, is adhered by supporting cells. Oxygen from the air diffuses into the hemolymph and is bound to hemocyanin. In most spiders there is a pair of tracheae. Through this tubular respiratory organ the oxygen is directly reaching the organs. See also circulation

Appendage of anterior epigynal margin

Hardened area of the cuticle, due to deposition of sclerotin. See also scutellum/scutum

Tufts of hairs with adhesive function, located distally on the legs

See scutellum/scutum

Most hairs and bristles are movable and articulated and have a mechanosensitive function. At their base there are sense cells which react to movements of the hairs. The extremely thin and usually very long trichobothria are only on legs and pedipalps and are extremely movable. They react to air currents and allows, as "remote tactile sense" some kind of "hearing". The short, steeply projecting, chemosensitive hairs on legs and pedipalps bearing a terminal pore opening, beneath which nerves end; they can be used, as contact chemoreceptors, for tasting and presumably for some kind of smelling

Sexual dimorphism

Phylogenetically, the spinnerets represent modified extremities of the 4. and 5. segment of the abdomen. Due to a division of the anlagen of the extremities into a smaller inner and a larger outer pair during embryonic development, 4 pairs of spinnerets emerge, which are only present in Mesothelae (see systematic). The anterior median pair is either reduced to a rudiment, the colulus, or to a cribellum. The spinning glands terminate in spigots on the surface of each spinneret. The Araneoidea (systematics) possess six different types of spinning glands and thus the greatest variety

Ventral plate of the prosoma

A catching thread provided with glue. Sticky threads are found in the orb webs of the Araneidae and Tetragnathidae, as well as in the webs of Theridiidae, Nesticidae, Linyphiidae, Theridiosomatidae, Mysmenidae and Anapidae. The glue originates from specialised spinning glands in the opisthosoma and coats a double silk thread as a thin layer. The glue condenses to fine droplets immediately after excretion

Basal, often ring-shaped sclerite of bulbus

A sense organ situated on the tarsus; mostly, it forms a spherical pit on the dorsal surface of each tarsus; it mainly serves as a humidity and temperature receptor

Seventh and last segment of the leg, sixth and last segment of the palp

An apophysis, partly or completely detached from tegulum

Carapace

Apophysis located terminally on embolic division of bulbus

Habitat loss and degradation are the most important threats to native spider species (in contrast to some tarantula species which are threatened by collecting). Partly, spiders are very closely associated to a certain type of microhabitat, which can be defined by various factors like climate, temperature, humidity, structural components and competition, etc. (see also habitat). Young spiders do often need different habitat types than adults, thus there have to be various adjoining macrohabitats (seasonal wandering). Generally, the closer a spider species is associated with a certain habitat, the more it is endangered. Only few, mostly disturbance-tolerating species had successfully colonised replacement habitats in the modern cultivated landscape. The emphasis on the endangerment is always linked to a decrease of the (total) population size. Rarity per se is only a potential measure of endangerment. Only in rare cases the decline of species can be documented, in most cases there is a lack of earlier data. Therefore, "Red Lists" resort to other criteria like the already mentioned association to a certain habitat and the endangerment of this habitats. The rarity (the decline, respectively) of a species can have various reasons: presumably, a rarely found species has very complex environmental requirements or only occurs in small, sparsely distributed or hard to reach habitats. Or microhabitats, which have been rarely studied due to methodical reasons (pitfall traps have been used for 40 years, studies of fallows have only been conducted for a short time). Without exact knowledge of the habitat preferences of such species, they will be only accidentally found and wrongly classified as "rare"

Fifth segment of the leg and palps

A process of the male palpal tibia

Finely branching internal tubes, part of the respiratory system. Normally, the posterior respiratory organ of the opisthosoma in spiders, in some dwarf form also often the anterior one. See also respiration, book lung and spiracle

A long, fine sensory hair on the legs and palps. The trichobothrium is embedded in a cup-shaped cuticular structure and reacts to air movements (also to acoustic pressure) with deflection whereby basal nerves are stimulated. Thus, some kind of "hearing" (perception of sound waves) is possible. The relative position of the trichobothria (e.g., on metatarsi of Linyphiidae) is often used as taxonomical character.

The second segment of the leg or palps

Outer part of uterus, in which the eggs are fertilised (in entelegyne spiders)

All spiders, except for the family Uloboridae, possess a pair of poison glands located in the prosoma. Their adjoining ducts leading to an opening at the tip of the cheliceral fangs. When catching large and/or aggressive prey, the victims are bitten and venom is injected. Spider venom is a mixture of many components. It contains, amongst other compounds, effective neurotoxic polypeptides, thus insects are completely paralysed also after the injection of only a small amount of venom. The bite of Cheiracanthium punctorium (Clubionidae) can cause strong pain, fever and ague, however, effects of the bite aren't dangerous and a medical treatment isn't needed (except for allergic reactions which can also be caused by insect bites). Worldwide, only about 20-30 of the 40'000 spider species are dangerously poisonous to man

The side of the body where the mouth is located (belly or lower side). See also dorsal

Internal genital organ of female, consisting of the spermathecae and at least one duct between spermatheca and genital opening

All spiders build webs for a more or less protected retreat; the orb weavers also use their web for catching prey. The very basal, recent spiders (the Mesothelae of south-east Asia) already build a silk-lined burrow and close the burrow with a very well camouflaged, silken lid. Other spiders use a silk-lined crevice under stones or bark or curled and silk-lined leaves as a retreat. There is an enormous variety in the shape of capture webs; their evolution is still not completely clear. Simple capture webs mostly consist of radial signal threads radiating from a retreat (e.g. Segestria). Agelenidae build a flat, slightly concave sheet web with a funnel-shaped retreat at one end (funnel webs). The cribellate threads and the sticky threads of the Araneoidea (e.g. Araneidae, Linyphiidae, Theridiidae) are specialised threads for catching prey. It is assumed that the possession of cribellum within the "higher" spiders (Araneomorphae) is the ancestral state; cribellum and calamistrum became reduced in many cases. Presumably, the Araneoidea also modified the orb web and replaced the cribellate catching thread with sticky thread. Later, the orb web itself was replaced with e.g. the various three-dimensional webs of Theridiidae and Linyphiidae. Other groups of spiders completely abandoned the web and now freely hunt their prey. See also systematics

The spider web can serve as a residence or retreat; the webs often protect the spider with its cocoon from enemies; furthermore, many spiders use their webs for capturing prey. In the simplest case, a silk-lined burrow is used as a retreat with clean walls and balanced climate. Almost all spider species, as well as web spiders, build a silken retreat where they hide during the rest period. Such retreats can also be built under stones, under bark or in coiled up leaves. An expansion of the margin of the retreat leads to a funnel-shaped web (e.g. Agelenidae). The spider, which hides in the retreat, is alarmed when an insect enters the web; the spider comes out and subdues the prey. Furthermore, there are three-dimensional webs which are attached to the vegetation (e.g. in many Theridiidae). The horizontal sheet can be detached from ground and take up a central position (e.g. in many Linyphiidae). The horizontal sheet can also be reduced, thus a two-dimensional, highly symmetric web results (e.g. the orb webs of many Araneidae). There have been various modifications and reductions during the evolution, so there are many web forms and their phylogeny is still mostly unclear. The evolution of cribellate threads or sticky threads have to be happened several times independent of each other, presumably, just as the transition from three-dimensional webs to orb webs, as well as many web spiders in various families abandoned their webs and now capture their prey without webs