INTRODUCTION

Today; Arthropods forms approximately 2/3 of the known animal species in the world. Phylum Arthropoda is the richest animal group in the world as species number and also as individual number. Also, insects which have  a large species diversity  in animal world are in this group.

Class Arachnida which exists in  phylum Arthropoda  and has a large spectrum which includes  different groups such as Spiders ,Scorpions, Uropygies, Solifugaes, Amblypygies, Opilionids, Acars, Pseudoscorpions, Palpigradies, Schzomids, Ricinuleies.

Spiders can inhabit in all types of the habitats and ecosystems. Spiders have a large spreading area, (from the poles to insides of the continents and from the surface of the sea to the 5000 m. elevations) in the world. However, most of the spiders live in lands, a few of spiders live in coasts or on the surface of fresh water and in it.

Generally, they dwell in the gardens, on the walls, under the eaves of houses by setting up  webs. Today, spiders, live in continental ecosystems are defined as effective predators of insects and arthropods.

 

Morphology

 The body separates in two parts, as prosoma and opisthosoma which are binded by a pedicel. The first pair of members  on  prosoma, are cheliserae. A pair of poison glands are located on binding side of cheliserea to prosoma. The poison duct of glands, connected to cheliserea opens to pincers which are in the tip of cheliserea and is used as bitting needle.

The poisons provide to eat preys more easily by causing paralysises. Second members are the pedipalps which are composed of six segments. Other members are the walking legs, there are 4 pairs of walking legs which are composed of  seven segments. Segments from basal plate to tip of legs are coxa, trochanter, femur, patella, tibia, metetarsus, tarsus. In front of the head, generally 8 (sometimes 6) eyes arrange in 2 or 3  rows.

Although opisthosoma has different sizes, it has not  an important role in systematic. Folium which resembles to a hearth or a leave  is situated on the dorsal. Anus is located on the back side of the opisthosoma, there are 3 pairs of spinerets just botom of it. The webs which emerge from the spinerets differs between species. Genital hole is located on front-middle part of the opisthosoma’s ventral. Tuber trache stigmas which are the opennings of respiratory system are situated on front-middle of spinerets.

 

Phenology

Spiderlings,  hatched from the eggs, are care by female spider for a few days, and then leave from nest and spin their webs in certain habitats and inhabit there. This shows that spiders have ability of spining webs before  maturing. Spiders are dioecious animals.

The males have a pair of testises which lie down on both sides of the opisthoma like tubes. Testises open to out by a sexual hole which is located on the back epigastic furrow. Pedipalpus is the male copulatory organ. In  the female reproduction system, ovaries resemble sacs which lie up from abdomen to back side. Spiders show sexual diamorphism. Generally male is smaller than female.

Chemotaxis and touching organs are well-developed for mating on species which show many different behaviours. They secrete chemicals called pheromone to attract opposite sex. At once time they can lay 300-3000 eggs. The eggs are carried in cocoon, sometimes connected to  mother. The spiderlings stay in cocoon, until first moulting. Hatched spiderlings look like matures and  a  larva period is not seen.

An immature spider moults 6-8 times until being mature. Spiders mature in certain periods of the year. Maturing generally begins at spring months and continues until autumn. Some species can mature during the year. In general they mature in May and June. The life span of spiders can change for 1-2 up to 10 years. Spiders, which live long time generally inhabit in tropical regions. Spider is divided into two suborders as Orthognatha and Labidognatha. Spiders in Orthognatha  have simple structures and survive in tropical and desert ecosystems.

 

Genital structure

Labidognatha is divided into two groups regarding to genital organs having whether complex or not. Haplojind and Entelejin spiders are the groups of Labidognatha. However haplojind generally have a simple palp and epijin, palp and epijin of  Entelejin spiders get a key-lock property because of the complex structure with extra chitin. Both male and female have a genital hole lieing down just at the hind of lungs in front-middle of opisthosoma. Pedipalp is copulatory organ of male spiders.

            And also, femur, patella or tibia and pedipalps can make extensions called “Apophyse” from tip to front, which can changes in thickness and length. In spite of existing tracheas, they do not show braching out in all parts of body like insects. They spread especially in opisthosoma.

 

Physiology

Feeding and digestive system

Most of the spiders are poliphage animals their diet forms of the juices which they suck from the bodies of insects and other animals.

First structure of the digestive system is the mouth and the following structure is a short pharynx. Pharynx opens to absorbtive stomach. There is a middle intestine which composed of cecums which have a sac structure. Small intestine enlarges in the opisthosoma reigon where it connected to liver with a few slim ducts. Following part of the small intestine has a slim, flat and pipelike structure. It enlarges again near the end to form a sac and opens out through the anus. Intestine is wrapped with digestive glands and liver in opistoma region.

 

Respiratory system

Respiration is carried out with trachea and book lungs. Book lungs generally composed of two sacs. Each sac have 15-20 leavelike lamellas wrapped with slim vessels. Air is taken in from the holes which open out and by this way, blood is refreshed. Altough, trachea exist in addition to book lungs, trachea do not branche in all parts of the body as in insects. Particulary they branch into opisthosoma.

 

Nervous System

            A brain (a ganglion with 2 lobes) is located on head region. A ganglion (subesephageal ganglion) group is located on breast region. Nervous cells are extended from the brain to ganglion. All above form nervous system. Although there are sense hairs on pedipalps and walking legs, main sense organs are admitted  as eyes. Generally they have 8 eyes of which size and prosture forms change between species. Spiders can clearly see objects far from 10-15 cm distance of it.

 

Circulatory System

There are 3 or 4 ostiumed heart which is located on dorsal part of opisthosoma, arteries and veins, a series of body cavity or sinuses in circulatory system of spiders.

         The heart has a shape like a contractile tube which is composed of muscle, and covered by pericardium. The 3 or 4 pairs holes, extended from heart to the pericardium cavity, are called “ostium”. An artery extends from heart towards hind of the body,and an aorta opens out to front side.

        Aorta reaches to tissues and organs in prosoma by branching out. The colorless blood, which has ameoboid and cells circulates into body cavities is purified in book lungs. Purified blood comes pericardium by veins and then return to heart passing trough the ostiums.

 

Excretory System

            The excretory system is composed of malpighian tubes and 2 coxal glands. Malpighian tubes are connected to small intestine. The two coxal glands are connected to basal plate of walking legs open out. Coxal glands were lost in some species. For this reason, it is hard to find the openings of the coxal glands in that species. Coxal glands are  homologs of the antennal glands of fresh water lobsters. However, these glands resemble to nephridiums of the annelids, there is not any cilium in their ducts. 

 

General Proporties

Camouflage, mocking and mimicry

Spiders have other adaptations which are more effective than  adaptations against to changings on enverionmental conditions, in order to protect themselves from their enemies. These protective adaptations include the behaviours such as using coouflage colours or complexly mocking. Most of the spiders have dull body colours and do not attract the attention. On the contrary Micrommata virencans and Araniella cucurbitina clearly have green body colours, to see them in their habitats is very difficult, because they live on the leaf.

            When spiders felldown, they pull their legs towards body and act like dead. This behaviour called catalepsy. Using this behavior in protecting from enemies is interesting because not only spiders mock, also ınsects mock spiders. For example, some of the fruit flies (Rhagoletis, Zonosemata) have dark marks on their wings which resemble the legs of the jumping spiders. So they look like moving spiders when they move their wings.

 

Wintering

85% of the fauna of spiders spend winter particulary in debris of leaf, which provide an isolation from the cold. Throughout this period, legs are in a position  wrapped to body and visible body surface is in a minimum level. The microhabitat under the debris protect spiders not only from high temparature changes but also from the drought. The spiders which are active in winter in the temprate zones are not resistant the cold but active in low temparatures compared with other spiders. The garden spiders are stable at 4˚C as the other spiders and die under -7˚C. The spiders,  spend winter inactive are more resistant to cold . Most of the (Araneus sp.)  can live at -20˚C in unprotect habitats. It hasn’t clearly determined how can they survive in such a cold temperature. But the presence of the glycerol as antifreeze in spider hemoelenf and because of having a higher glycerol consantration in winter months compared to summer months are the clues for illimunating the matter. But also some ampasses attract the attention.

 

Adaptations

            Spiders have developed various adaptations against to unsuitable conditions such as cold temperature, moistness, flood and shortage. Today, winter ecology and resistance against to cold of spiders which are active in winters are being studied. Spiders increase their resistance against to cold by taking shelter in  microhabitats. And they decrease their metobolism rate and prepare for winter.

 

Poisons of spiders

            All spiders have poison glades on their cheliserea and inject their poisons into preys by the fangs on the tip of cheliserea. The nerotoxic poisons of spiders cause paralysis on the respiratory system. Deaths by poisons are seen on children because of respiration unsufficiency. Spiders dwell in temperate zones are not very poisonous, their effects do not cause human deaths. But spiders live in tropical regions are very poisonous that they can cause serious promlems for people. Spider species that have mortal effects on humans are  mostly found in Araneidae, Argiopidae, Clubionoidae, Eresidae, Loxoscelidae, Lycosidae, Theriidae families. However tarantulas  are giant spiders, they are less dangerous on the contrary  the common opinion.

 

POISONING

The subtances cause death by effecting chemical and physiological structures of the body when taken into body adequate amounts are called toxins or poisons. And the clinic symptoms of damages that they do in tissues are called poisoning.

Effects of poisons can change depanding on their doses and taking  routes. Features of the poisons such as molecular weight, binding capacity to proteins and features of the structures that they effect are important in poisoning.

Poisons mainly effect the central nervous system. Related to this effect they hind the other systems in the body depanding on the features of the poisons.

In acute poisonings, the sypmtoms such as decrease in irritability,  hallusination and coma can be seen. In cronic poisoning, damages on nervous system such as decrease in sensing of organs can  occur.

 

There are three routes of poisoning;

1. Orally; Food poisonings, poisonings with drugs, with chemical subtances and with alchol.

2. By respiration; Poisoning with carbondioxide and other poisonous gasses. 

3. Absorbing by skin; Poisoning with the contacts of poisonous gasses, with peptisides and because of biting and stinging of snakes, scorpions, spiders and other venomous animals.

It is important to know time and route of poisoning and also amount of the poison for the first aid in acute poisonings.

 

Spider Bites

There are large venom glands on the basal plate of cheliserea in spiders. Therefore, almost all of the 20.000 species of spiders are venomous. These glands open out from the tip segment of the cheliserea (this segment is called fang) sink into prey and inject the poison. The musculars around the glands are important for injection.

A few spider species are venomous for humans. Because, the fangs of most species which have effective poisons are too short or fragile to penetrate into human skin. But they can be effective for children and can cause deaths.

Spiders in genus Phonoeutria which live in South America have the strongest neorotoxic poison ever known and they are very dangerous for humans. Spiders in genus Lactrodectus known as black widow spiders which have the poisons effective on the neuromuscular transmission form another poisonous group. Also, spiders in genus Loxoceles and in family Argyronetidae (water spiders ) have efffective poisones.

Allmost all of the spider venoms are neurotoxic. These poisons effects to neurory system and related this effect , muscular rigitidies and deaths can be seen.

In contary to common opinion, small spiders have stronger poisons when comprised with the poisons of  big spiders. Tarantulas are not as posionous as they are known.

 

 

Symptoms

Immediate pain, burning, swelling, redness and formication are the symptoms at the bite site. Double fangs marks may be seen at the site. Cramping pain and muscle rigidity in the stomach, chest and back are the symptoms in the patient. Haedage, itching, sweating, dizziness, nausea and vommiting, paralysis expecially in the legs are the other symptoms. Because of the diffucult in respiration deaths can occur particullary in children. Also gangrenne is another important result of spider venoms.

 

 

First Aid

Up site of the biting area is tighted with a string or a cloth to slow the circulation of the blood. The biting area must be washed with soap and water. Appling cold with ice wrapped in a cloth or a cold, wet clothes is effective to halt  the pain and also asetominophen may be given for to stop pain. It is important to apply an antibiotic cream against to infections, particullary in children. Amoniac or permanganate, also can be used against to infections. After these meassures, patient must be carried to a hospital for further treatments   might be required depending on the effect of  the poison.

 

Webs

            All of spiders have the ability of producing filamantous webs those reflect the differences between species, therefore, webs are important for classification. Spiders can spin the webs between the branches of trees, leaf, into the bushes  on the grasses and ground, under the stores on the walls of houses and in the cellars. Various types of spider webs  resemble to the circular concave tents or convex tents, funnels, irregular and thiğht fishing nets are present. Spider webs are olso use as a spreading vehicle . The silks those are produced by spiders are structral  proteins called fibrion. Silks emerge from the spinnerets  on the tip of the ophistosoma in a liguid from then  became sticky fibers when they contact with air. Therefore insects immedıately stick to the web when they touch it while flying.

 

Courtship

            Spiders have developed various behaviours to communicate each other. Mechanic, chemical and visual signs are important for courting. Particularly receptors perceive the mechanic signs such as vibrations on the web are important. Sighs which are generated by web spiders by vibrating are specific for species and probably they are edequate for mating. Ground spiders also generate vibrating signs in the mating period. They deliver the vibrations through the solid objects such as soil and leaf  or through the air as a sound.

 

Sounding

            As in ınsecta, spiders principally sound , a trumpet banging sound by using their legs and abdomen, a metal filing sound using their stidulation organs and also make sound by the vibration of abdomen and legs.

 

Agricultural struggle

            Most of the preys of the predators in agricultiral ecosystem consist of insects which have a soft body such as Collembola, Diptera  and Afids. There are two layers in agriculturral ecosystoms where the spiders are presented. Surface zone of ground and vegatation zone. Different spiders groups are presented in any of the zones. Some pestisids which are carried out on agricultural areas cause  important dicreases on the spider populations. Pestisids effect not only the harmfull ınsects but also the spiders which are the predators of these insects. Agricultural and chemical tecniques must be chosen carefully and activity of the spiders in agricultural areas must be protected and developed.

 

Enemies of spiders

            Spiders have many enemies among the fishes, amphibia, reptilies, birds and particulary rodents in vertabrate. Most of the fishes, particulary salmon trout can hunt spiders on the water surface. It is guessed  that  toads live on spiders. It is known that spiders are  part of the nourısment lıst of the reptilies, but reptilies have not got much effects on spider population. Only a few enemies of spiders are mammals,  1-2 % of the nourisment  of the insectivirous such as hedgehogs and moles consist of spiders. Bats also eat spiders. But the essential enemies of spiders are themselves. Some species live on other spider species. Because of the cannibalism, there is a natural stabilization on the population of the species.            

                      

           

 

 

 

 

Referances

 

Brignoli, P. M., 1983. A Catalogue of the Araneae 1940-1981, Part I and II.  Manchester University Press. Manchester. 754 p.

Foelix, R. F., 1982. Biology of Spiders. Harvard University Press. Cambridge. 514 p.

Nentwig, W., 1968. Non-webbuilding spiders: prey specialists or generalists. Oecologia (Berlin) 69: 571-576.

Nentwig, W., 1987. Ecophysiology of spiders. Regensburg University, Institute of Zoology. Regensburg. 815 p.

Tyschchenko, V. P., 1971, Identification Key to Spiders of the European USSR, Opred Faune USSR 105, Leningrad. 281 p. (in Russian).

 

 

 

 

 

 

 

 

 

 

 

 

 

INTRODUCTION

Today; Arthropods forms approximately 2/3 of the known animal species in the world. Phylum Arthropoda is the richest animal group in the world as species number and also as individual number. Also, insects which have  a large species diversity  in animal world are in this group.

Class Arachnida which exists in  phylum Arthropoda  and has a large spectrum which includes  different groups such as Spiders ,Scorpions, Uropygies, Solifugaes, Amblypygies, Opilionids, Acars, Pseudoscorpions, Palpigradies, Schzomids, Ricinuleies.

Spiders can inhabit in all types of the habitats and ecosystems. Spiders have a large spreading area, (from the poles to insides of the continents and from the surface of the sea to the 5000 m. elevations) in the world. However, most of the spiders live in lands, a few of spiders live in coasts or on the surface of fresh water and in it.

Generally, they dwell in the gardens, on the walls, under the eaves of houses by setting up  webs. Today, spiders, live in continental ecosystems are defined as effective predators of insects and arthropods.

 

Morphology

 The body separates in two parts, as prosoma and opisthosoma which are binded by a pedicel. The first pair of members  on  prosoma, are cheliserae. A pair of poison glands are located on binding side of cheliserea to prosoma. The poison duct of glands, connected to cheliserea opens to pincers which are in the tip of cheliserea and is used as bitting needle.

The poisons provide to eat preys more easily by causing paralysises. Second members are the pedipalps which are composed of six segments. Other members are the walking legs, there are 4 pairs of walking legs which are composed of  seven segments. Segments from basal plate to tip of legs are coxa, trochanter, femur, patella, tibia, metetarsus, tarsus. In front of the head, generally 8 (sometimes 6) eyes arrange in 2 or 3  rows.

Although opisthosoma has different sizes, it has not  an important role in systematic. Folium which resembles to a hearth or a leave  is situated on the dorsal. Anus is located on the back side of the opisthosoma, there are 3 pairs of spinerets just botom of it. The webs which emerge from the spinerets differs between species. Genital hole is located on front-middle part of the opisthosoma’s ventral. Tuber trache stigmas which are the opennings of respiratory system are situated on front-middle of spinerets.

 

Phenology

Spiderlings,  hatched from the eggs, are care by female spider for a few days, and then leave from nest and spin their webs in certain habitats and inhabit there. This shows that spiders have ability of spining webs before  maturing. Spiders are dioecious animals.

The males have a pair of testises which lie down on both sides of the opisthoma like tubes. Testises open to out by a sexual hole which is located on the back epigastic furrow. Pedipalpus is the male copulatory organ. In  the female reproduction system, ovaries resemble sacs which lie up from abdomen to back side. Spiders show sexual diamorphism. Generally male is smaller than female.

Chemotaxis and touching organs are well-developed for mating on species which show many different behaviours. They secrete chemicals called pheromone to attract opposite sex. At once time they can lay 300-3000 eggs. The eggs are carried in cocoon, sometimes connected to  mother. The spiderlings stay in cocoon, until first moulting. Hatched spiderlings look like matures and  a  larva period is not seen.

An immature spider moults 6-8 times until being mature. Spiders mature in certain periods of the year. Maturing generally begins at spring months and continues until autumn. Some species can mature during the year. In general they mature in May and June. The life span of spiders can change for 1-2 up to 10 years. Spiders, which live long time generally inhabit in tropical regions. Spider is divided into two suborders as Orthognatha and Labidognatha. Spiders in Orthognatha  have simple structures and survive in tropical and desert ecosystems.

 

Genital structure

Labidognatha is divided into two groups regarding to genital organs having whether complex or not. Haplojind and Entelejin spiders are the groups of Labidognatha. However haplojind generally have a simple palp and epijin, palp and epijin of  Entelejin spiders get a key-lock property because of the complex structure with extra chitin. Both male and female have a genital hole lieing down just at the hind of lungs in front-middle of opisthosoma. Pedipalp is copulatory organ of male spiders.

            And also, femur, patella or tibia and pedipalps can make extensions called “Apophyse” from tip to front, which can changes in thickness and length. In spite of existing tracheas, they do not show braching out in all parts of body like insects. They spread especially in opisthosoma.

 

Physiology

Feeding and digestive system

Most of the spiders are poliphage animals their diet forms of the juices which they suck from the bodies of insects and other animals.

First structure of the digestive system is the mouth and the following structure is a short pharynx. Pharynx opens to absorbtive stomach. There is a middle intestine which composed of cecums which have a sac structure. Small intestine enlarges in the opisthosoma reigon where it connected to liver with a few slim ducts. Following part of the small intestine has a slim, flat and pipelike structure. It enlarges again near the end to form a sac and opens out through the anus. Intestine is wrapped with digestive glands and liver in opistoma region.

 

Respiratory system

Respiration is carried out with trachea and book lungs. Book lungs generally composed of two sacs. Each sac have 15-20 leavelike lamellas wrapped with slim vessels. Air is taken in from the holes which open out and by this way, blood is refreshed. Altough, trachea exist in addition to book lungs, trachea do not branche in all parts of the body as in insects. Particulary they branch into opisthosoma.

 

Nervous System

            A brain (a ganglion with 2 lobes) is located on head region. A ganglion (subesephageal ganglion) group is located on breast region. Nervous cells are extended from the brain to ganglion. All above form nervous system. Although there are sense hairs on pedipalps and walking legs, main sense organs are admitted  as eyes. Generally they have 8 eyes of which size and prosture forms change between species. Spiders can clearly see objects far from 10-15 cm distance of it.

 

Circulatory System

There are 3 or 4 ostiumed heart which is located on dorsal part of opisthosoma, arteries and veins, a series of body cavity or sinuses in circulatory system of spiders.

         The heart has a shape like a contractile tube which is composed of muscle, and covered by pericardium. The 3 or 4 pairs holes, extended from heart to the pericardium cavity, are called “ostium”. An artery extends from heart towards hind of the body,and an aorta opens out to front side.

        Aorta reaches to tissues and organs in prosoma by branching out. The colorless blood, which has ameoboid and cells circulates into body cavities is purified in book lungs. Purified blood comes pericardium by veins and then return to heart passing trough the ostiums.

 

Excretory System

            The excretory system is composed of malpighian tubes and 2 coxal glands. Malpighian tubes are connected to small intestine. The two coxal glands are connected to basal plate of walking legs open out. Coxal glands were lost in some species. For this reason, it is hard to find the openings of the coxal glands in that species. Coxal glands are  homologs of the antennal glands of fresh water lobsters. However, these glands resemble to nephridiums of the annelids, there is not any cilium in their ducts. 

 

General Proporties

Camouflage, mocking and mimicry

Spiders have other adaptations which are more effective than  adaptations against to changings on enverionmental conditions, in order to protect themselves from their enemies. These protective adaptations include the behaviours such as using coouflage colours or complexly mocking. Most of the spiders have dull body colours and do not attract the attention. On the contrary Micrommata virencans and Araniella cucurbitina clearly have green body colours, to see them in their habitats is very difficult, because they live on the leaf.

            When spiders felldown, they pull their legs towards body and act like dead. This behaviour called catalepsy. Using this behavior in protecting from enemies is interesting because not only spiders mock, also ınsects mock spiders. For example, some of the fruit flies (Rhagoletis, Zonosemata) have dark marks on their wings which resemble the legs of the jumping spiders. So they look like moving spiders when they move their wings.

 

Wintering

85% of the fauna of spiders spend winter particulary in debris of leaf, which provide an isolation from the cold. Throughout this period, legs are in a position  wrapped to body and visible body surface is in a minimum level. The microhabitat under the debris protect spiders not only from high temparature changes but also from the drought. The spiders which are active in winter in the temprate zones are not resistant the cold but active in low temparatures compared with other spiders. The garden spiders are stable at 4˚C as the other spiders and die under -7˚C. The spiders,  spend winter inactive are more resistant to cold . Most of the (Araneus sp.)  can live at -20˚C in unprotect habitats. It hasn’t clearly determined how can they survive in such a cold temperature. But the presence of the glycerol as antifreeze in spider hemoelenf and because of having a higher glycerol consantration in winter months compared to summer months are the clues for illimunating the matter. But also some ampasses attract the attention.

 

Adaptations

            Spiders have developed various adaptations against to unsuitable conditions such as cold temperature, moistness, flood and shortage. Today, winter ecology and resistance against to cold of spiders which are active in winters are being studied. Spiders increase their resistance against to cold by taking shelter in  microhabitats. And they decrease their metobolism rate and prepare for winter.

 

Poisons of spiders

            All spiders have poison glades on their cheliserea and inject their poisons into preys by the fangs on the tip of cheliserea. The nerotoxic poisons of spiders cause paralysis on the respiratory system. Deaths by poisons are seen on children because of respiration unsufficiency. Spiders dwell in temperate zones are not very poisonous, their effects do not cause human deaths. But spiders live in tropical regions are very poisonous that they can cause serious promlems for people. Spider species that have mortal effects on humans are  mostly found in Araneidae, Argiopidae, Clubionoidae, Eresidae, Loxoscelidae, Lycosidae, Theriidae families. However tarantulas  are giant spiders, they are less dangerous on the contrary  the common opinion.

 

POISONING

The subtances cause death by effecting chemical and physiological structures of the body when taken into body adequate amounts are called toxins or poisons. And the clinic symptoms of damages that they do in tissues are called poisoning.

Effects of poisons can change depanding on their doses and taking  routes. Features of the poisons such as molecular weight, binding capacity to proteins and features of the structures that they effect are important in poisoning.

Poisons mainly effect the central nervous system. Related to this effect they hind the other systems in the body depanding on the features of the poisons.

In acute poisonings, the sypmtoms such as decrease in irritability,  hallusination and coma can be seen. In cronic poisoning, damages on nervous system such as decrease in sensing of organs can  occur.

 

There are three routes of poisoning;

1. Orally; Food poisonings, poisonings with drugs, with chemical subtances and with alchol.

2. By respiration; Poisoning with carbondioxide and other poisonous gasses. 

3. Absorbing by skin; Poisoning with the contacts of poisonous gasses, with peptisides and because of biting and stinging of snakes, scorpions, spiders and other venomous animals.

It is important to know time and route of poisoning and also amount of the poison for the first aid in acute poisonings.

 

Spider Bites

There are large venom glands on the basal plate of cheliserea in spiders. Therefore, almost all of the 20.000 species of spiders are venomous. These glands open out from the tip segment of the cheliserea (this segment is called fang) sink into prey and inject the poison. The musculars around the glands are important for injection.

A few spider species are venomous for humans. Because, the fangs of most species which have effective poisons are too short or fragile to penetrate into human skin. But they can be effective for children and can cause deaths.

Spiders in genus Phonoeutria which live in South America have the strongest neorotoxic poison ever known and they are very dangerous for humans. Spiders in genus Lactrodectus known as black widow spiders which have the poisons effective on the neuromuscular transmission form another poisonous group. Also, spiders in genus Loxoceles and in family Argyronetidae (water spiders ) have efffective poisones.

Allmost all of the spider venoms are neurotoxic. These poisons effects to neurory system and related this effect , muscular rigitidies and deaths can be seen.

In contary to common opinion, small spiders have stronger poisons when comprised with the poisons of  big spiders. Tarantulas are not as posionous as they are known.

 

 

Symptoms

Immediate pain, burning, swelling, redness and formication are the symptoms at the bite site. Double fangs marks may be seen at the site. Cramping pain and muscle rigidity in the stomach, chest and back are the symptoms in the patient. Haedage, itching, sweating, dizziness, nausea and vommiting, paralysis expecially in the legs are the other symptoms. Because of the diffucult in respiration deaths can occur particullary in children. Also gangrenne is another important result of spider venoms.

 

 

First Aid

Up site of the biting area is tighted with a string or a cloth to slow the circulation of the blood. The biting area must be washed with soap and water. Appling cold with ice wrapped in a cloth or a cold, wet clothes is effective to halt  the pain and also asetominophen may be given for to stop pain. It is important to apply an antibiotic cream against to infections, particullary in children. Amoniac or permanganate, also can be used against to infections. After these meassures, patient must be carried to a hospital for further treatments   might be required depending on the effect of  the poison.

 

Webs

            All of spiders have the ability of producing filamantous webs those reflect the differences between species, therefore, webs are important for classification. Spiders can spin the webs between the branches of trees, leaf, into the bushes  on the grasses and ground, under the stores on the walls of houses and in the cellars. Various types of spider webs  resemble to the circular concave tents or convex tents, funnels, irregular and thiğht fishing nets are present. Spider webs are olso use as a spreading vehicle . The silks those are produced by spiders are structral  proteins called fibrion. Silks emerge from the spinnerets  on the tip of the ophistosoma in a liguid from then  became sticky fibers when they contact with air. Therefore insects immedıately stick to the web when they touch it while flying.

 

Courtship

            Spiders have developed various behaviours to communicate each other. Mechanic, chemical and visual signs are important for courting. Particularly receptors perceive the mechanic signs such as vibrations on the web are important. Sighs which are generated by web spiders by vibrating are specific for species and probably they are edequate for mating. Ground spiders also generate vibrating signs in the mating period. They deliver the vibrations through the solid objects such as soil and leaf  or through the air as a sound.

 

Sounding

            As in ınsecta, spiders principally sound , a trumpet banging sound by using their legs and abdomen, a metal filing sound using their stidulation organs and also make sound by the vibration of abdomen and legs.

 

Agricultural struggle

            Most of the preys of the predators in agricultiral ecosystem consist of insects which have a soft body such as Collembola, Diptera  and Afids. There are two layers in agriculturral ecosystoms where the spiders are presented. Surface zone of ground and vegatation zone. Different spiders groups are presented in any of the zones. Some pestisids which are carried out on agricultural areas cause  important dicreases on the spider populations. Pestisids effect not only the harmfull ınsects but also the spiders which are the predators of these insects. Agricultural and chemical tecniques must be chosen carefully and activity of the spiders in agricultural areas must be protected and developed.

 

Enemies of spiders

            Spiders have many enemies among the fishes, amphibia, reptilies, birds and particulary rodents in vertabrate. Most of the fishes, particulary salmon trout can hunt spiders on the water surface. It is guessed  that  toads live on spiders. It is known that spiders are  part of the nourısment lıst of the reptilies, but reptilies have not got much effects on spider population. Only a few enemies of spiders are mammals,  1-2 % of the nourisment  of the insectivirous such as hedgehogs and moles consist of spiders. Bats also eat spiders. But the essential enemies of spiders are themselves. Some species live on other spider species. Because of the cannibalism, there is a natural stabilization on the population of the species.            

                      

           

 

 

 

 

Referances

 

Brignoli, P. M., 1983. A Catalogue of the Araneae 1940-1981, Part I and II.  Manchester University Press. Manchester. 754 p.

Foelix, R. F., 1982. Biology of Spiders. Harvard University Press. Cambridge. 514 p.

Nentwig, W., 1968. Non-webbuilding spiders: prey specialists or generalists. Oecologia (Berlin) 69: 571-576.

Nentwig, W., 1987. Ecophysiology of spiders. Regensburg University, Institute of Zoology. Regensburg. 815 p.

Tyschchenko, V. P., 1971, Identification Key to Spiders of the European USSR, Opred Faune USSR 105, Leningrad. 281 p. (in Russian).