Information about the spiders
An Introduction to the Spider
Spiders have a
body divided into two parts instead of three compared to insects, and eight
legs instead of six, and thus they do not follow insects by classification, and
the spiders are characterized by the great color diversity, and this helps to
confine them to specific families, some of them have dark colored bodies spread
by bright spots, Such as: the tropical gas spider, and there is another family
that has brown or black bellies with lighter colors, such as wolf spiders,
while the trapdoor spider has a large head whose color usually differs from the
color of their stomachs, and it should be noted that the length of the spider's
body ranges between 0.5 mm to 90 Approximately mm.
Scientific classification of the spider
The main classification
There are many
types of arachnids spread around the world, which scientifically belong to
multiple genera that fall under various families belonging to the order
Tarantula (scientific name: Araneae), which belongs to the class Arachnids
(scientific name: Arachnida) within the class above the class of true antlers
(scientific name) : Euchelicerata), which falls under the phylum Craniasis
(scientific name: Chelicerata) of the division of arthropods (scientific name:
Arthropoda) within the higher phylum Osteophytes (scientific name: Ecdysozoa),
which falls under the lower kingdom Proto-stomata (scientific name:
Protostomia) under Awelem is bilateria (scientific name: Bilateria) within the
animal kingdom.
Classification of families
The number of
spiders known around the world reaches more than 46,700 species, classified
within nearly 110 families, where spiders are divided into three main orders,
namely:
Jaw forceps
spiders: Jaw forceps spiders (scientific name: Labidognatha) are distinguished
by the presence of foot tentacles located behind specialized front appendages
called hooks under a horn or bone shield, and they also contain a distinct
respiratory system from the clerical lungs in addition to the bronchi that may
act as a respiratory system Instead, as for the heart, it contains three
openings and sometimes two, and a double series of divided nerve ganglia, as several
families fall under this arrangement, including:
Family of jumping
spiders (scientific name: Salticidae).
Family of levae
(scientific name: Linyphiidae).
A family of
spiders (scientific name: Araneidae).
Family of wolf
spiders (scientific name: Lycosidae).
Family of
homophones (scientific name: Theridiidae).
Tarantula spiders:
jaw spiders or tarantulas (scientific name: Orthognatha) live in warm climates,
and when the respiratory system is addressed in this suborder, it is
represented by two pairs of the epigastric lung, and the heart often contains
four small openings and a double chain of nerve ganglia. The following families
descend under this order: (Theraphosidae), (Dipluridae), (Ctenizidae),
(Hexathelidae), (Atypidae).
Segmented spiders:
It contains one family called (Liphistiidae) under which about 100 species of
spiders are included, they are found in Japan to the southeast of Asia, and
segmented or segmented spiders (scientific name: Mesothelae) can be
distinguished in this order by the segmented abdomen from 7 to 18 Part, and 8
spindles of silk in the middle of the abdomen, and spiders in the frontal
region of the prosoma have 18 knots separated from each other more than other
arrangements, and the heart contains 5 pairs of small openings, in addition to
two pairs of the clerical lung.
The body composition of the spider
The body of the
spider is divided into only two parts, namely: the prosoma (in English:
Cephalothorax) or the head - the chest, and the abdomen (in English: Abdomen),
and there is a narrow knot in the middle that connects the two areas together
called the leg (in English: Pedicel), and the parts come in detail:
Prosoma
The upper and
lower parts of the prosoma are covered with protective structures; The upper
side is covered by the horny shield (in English: carapace), while the lower
side is covered by the sternum (in English: the sternum) in addition to the
lower appendages called the lip (in English: labium), [6] and the prosoma
consists of a number of external organs:
Eye: The spider
moves and searches for its prey by relying on touch, vibration and taste more
than it relies on vision, but few of them have good eyesight that they use for
building, hunting, and wandering, in addition to identifying their mates and
predators. Some types of spiders have 8 eyes and others have six or The lowest,
best spiders to see are: the jumping spider, the long legged spider, and the
wolf spider.
Fovea: The
pectoral muscles are internally connected to a point called the fovea, located
in the middle of the spine.
The mouth region:
This region consists of two jaws that contain fangs, hooks, or hooks called
chelicerae, in addition to an upper plate (The labrum) and a lower plate (in
English: The labium) that form the upper and lower part of the mouth, and it
also contains On a row to chop food in the upper jaw.
Foot tentacles:
The spider is able to sense, touch, and taste, in addition to mating with
pedipalps in males.
Feet: The spider
has four pairs of feet, some of which contain two claws, such as: jumping
spiders, where these spiders can stand on smooth and sloping surfaces due to
the presence of dense tufts of hair that improve the process of adhesion, while
others contain three claws; As a net weaver, spiders also have a number of
sensory organs on their legs, such as: the foot tentacles and hair, in addition
to small holes in most parts of their body, so that they can taste, smell
odors, and feel vibrations. The prosoma also includes the following internal
organs:
Muscles: where the
limbs and jaws move with the help of muscles.
Cerebral ganglia:
Ganglia are made up of a group of nerve tissues.
Venom glands:
Spiders kill their prey with the toxin produced by the venom glands.
Muscular stomach:
Liquid food reaches the esophagus, pharynx, and intestine by being pumped by
the muscular stomach or stomach muscles.
Belly
The abdomen of the
spider expands when feeding and developing eggs with the help of the thin and
flexible skin that covers it, and when spinning silk and mating, the abdomen
moves with the help of the septum that separates it from the prosoma, and for
the external organs that make up the abdomen:
The book lung
cover: The book lung covers the sensitive organs inside the spider.
Genital orifice:
The eggs or sperms reach the reproductive system, which is located in front of
the clerical lung pair, after they are released from the genital orifice, and
there is another opening called the orifice or the external genital organelles
(in English: epigynum) in the spiders Ritelloid shape.
Spinners: Spinners
have 4 to 6 spinnerets to produce silk.
As for the
internal organs in the abdomen, they are:
Lung lung:
Tarantula spiders have two pairs of book lungs, in which the exchange of gases
between air and blood occurs after entering it through small openings covered
with a layer of very thin skin and linked to cavities that end with book-like
pages attached to pillars that prevent them from sticking together. Some small
spiders exchange gases across a thin layer of skin. They do not have
respiratory organs due to their presence in moist and sheltered places.
Silk glands Silk
consists of a liquid protein that is produced by the silk glands.
Heart: The heart
is located in the center of the spider's body, where blood is pumped to parts
of the body through vessels or cavities and then gradually returned to it, and
the circulatory system is open to it.
Hind intestine:
Food is absorbed in the hind-gut, and it contains a sac of secretory organelles
called Malphigian tubules, which play the role of the kidneys in the spider.
Skin
The body of the
spider consists of internal and external organs; Such as the skin, the muscles,
the respiratory system, and the digestive system, in addition to the genitals,
and the skin, skin, or a solid external structure is characterized by that it
is composed of several layers of protein and chitin that cover the body of the
spider from the outside, and its function is to provide points of connection or
contact with the muscles, in addition to regulating pressure Blood, as it
contains hair and nerve appendages that represent the spider's senses, and
lines the front and back intestine, trachea, and the sperm storage system in
females, and the skin reduces water loss by containing a thin layer of wax.
Spiders fix their
muscles on a semi-rigid hydrostatic structure that surrounds the body of the
spider from the inside consisting of cavities filled with fluid, and the fluid
pressure acts as a stabilizer for the muscles around it, to maintain the body’s
shape and function, so blood pressure is affected by the change in heartbeat,
contraction and relaxation of the muscles.
The life cycle of a spider
The life cycle of
a spider begins from the reproductive process by placing approximately a
thousand fertilized eggs in a silk bag after mating. Male spiders put sperm
into a web of their own to pull them to the foot tentacles to be inserted into
the genital openings of the female that stores them inside to choose sperm
capable and appropriate for fertilization Eggs, [10] and the spider's life
cycle goes through three stages:
The embryonic
stage (eggs): This stage occurs after mating, so that the eggs are kept in a
strong silky bag to protect it, and here the way some spiders care for and
guard the eggs differs, for example: the mother spider carries the bag with her
until they hatch, such as: the wolf spider, and some carry it for ten days on
They appear, and for some others, the eggs are left in a safe place until they
hatch, and this usually takes a few weeks.
Pre-growth stage:
This stage begins after the eggs hatch into small spiderlings that move away
from each other by walking, bulging or ballooning, which enables them to travel
short distances and sometimes long, by weaving silk threads It releases it from
its spindle to blow with the wind and move from one place to another, and with
the passage of time the size of the small spiders increases through the process
of moulting, as they replace their external structure several times and get rid
of it, so the number of moults that occur ranges between 5 to 10 until they
reach the stage of maturity.
Adulthood: The
spider reaches the stage of sexual maturity in adulthood, where a new life
cycle begins upon mating, and the life span of the spider varies in different
types, but it lives from about one to two years, and what should be noted is
that the life span of females is longer than males who often die after mating .
Spider food
The spider feeds
on many organisms; Like insects and other spiders, in addition to small birds,
frogs, reptiles and others, it also has the ability to sense the movement of
prey, see it and distinguish between them, and what should be noted is that
spiders have pointed front appendages such as fangs at the front of the head
and chest called chelicerae, in addition to To pedipalps to catch prey, as
spiders can obtain their food in several ways, as they may produce a toxin with
the help of some enzymes to paralyze the movement of the prey, causing tissue
damage and death, or some spiders may penetrate the skin and suck blood using
special mouth parts to do so Or by weaving a web of silk threads that stick to
the prey.
Habitat of the spider
All continents of
the world except Antarctica are home to the spider, but many species live in
the tropics more than temperate, and they are found in the Himalayas at an
altitude of approximately 5,000 meters, in addition to most of them live on
land except for the Eurasian species that lives on the water surface Fresh,
there are a few species of spiders that make their living on the surface of
beaches, fresh and salt water.
Cobwebs
The spider makes
cobwebs from a strong protein filament called silk, which produces seven
different types of it, so the spiders are classified according to the type of
web they make, including: the tangled web spider, the circular web spinner, the
funnel web spider, and the incubator web spider, [14] Spiders produce silk for
several purposes, including: protecting themselves from falling, making egg
bags, wrapping prey by making nets, and building their own housing and burrows.
The process of
producing silk is carried out by pressing the spider to its abdomen after
making it by several types of silk glands that have channels connected to the
spindles and have external openings, where the muscle valves control the rate
of silk flow, and there are 7 types of glands in spiders weaving networks,
including:
Ring Glands: The
silk produced by the Aciniform glands encapsulate the prey.
The ampullate
glands produce silk that is used for drawing sutures.
Cylindrical
glands: The cylindrical glands produce the silk used to make abdominal bags.
Silk glands above
the stomach: The silk glands above the stomach (Epigastric silk glands) produce
silk that is used to provide a surface for placing sperm on it, so it is found
in male spiders.
Spider venom and stings
Spider venom does
not pose a threat to humans except in some species. Such as the black widow
spider, which has a strong neurotoxin, and the brown recluse spider, whose
toxin spoils the tissues and leaves a deep hole in it. [17] The venom of the
spider is made from a mixture of chemicals such as proteins, peptides, sugars
and other substances to kill its prey or Paralyzing them, or breaking down
tissues in order to obtain their nourishment in a liquid state, [18] It is
worth noting that all spiders produce venom except for the family of
"Uloboridae", where they lack specialized poison glands [19] and
there are two types of toxins; They:
Neurotoxins:
Neurotoxic Venoms affect the nervous system, as they prevent nerve impulses
from reaching the muscles, where stiffness and contraction occur in muscles,
disrupting body functions, and may paralyze the entire nervous system due to
increased production of neurotransmitters. Such as acetylcholine and
norephinephrine.
Cytotoxins:
cytotoxic venoms affect tissues, causing skin ulcers and blisters, and causing
damage and death.
The difference between a female spider and a male spider
Color: The colors
of spiders vary from one species to another, but usually the colors of male
spiders are more vivid than the female, as the male black widow spider appears
in its light colors, and on its back are red or pink spots, while the female is
black in color and on her stomach a red spot in the form of an hourglass
However, this trait does not apply to the golden silk spider, as the female has
a more vivid color than the dark brown male.
Size: It is
believed that the size of the females is greater due to their need to produce
offspring, as the female golden silk spider is 6 times the length of the male,
in addition to several other species as well, such as: the black widow and the
jumping spider.
Legs: Male spiders
have longer legs than females, because they need them in the process of
catching, and while they roam farther from the net in which the female stays.
Foot tentacles: It
can be observed through a microscope that the foot tentacles in males are more
swollen than in females.
The amount of
venom: Female spiders need more venom to protect their web that does not leave
it, and it should be noted that the venom bags of some male spiders are
ineffective.
Spiders' life
span: Spiders die before reaching old age due to predators, parasites, or
diseases. Most of them live for several months, and some for years if they
remain in their habitat and burrow. Females have a longer life compared to
males, for example a female tarantula lives for 25 years, that is, 15 years
more than males.
Sana Aldwikat
Mawdoo3
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