Tarantula

The tarantula consists of a group of large, generally hairy Theraphosidae spiders. Technically no hairs are present on the tarantula skin but they are bristles. Currently, 1,010 species have been identified. The term tarantula is often used to describe members of the tarantula family, although many other members of the same order that is Mygalomorphae are often referred to as "tarantulas" or "false tarantulas". Some of the more common species have become popular in the exotic pet trade. The hair of many New World species raised as pets can irritate the skin and, in extreme cases, can damage the eyes. We will learn more about all tarantula species and more about ‘what is a tarantula’.  

Tarantula Spider

Here, we will understand in brief ‘what is a tarantula’. Like all arthropods, tarantulas are invertebrates that depend on the exoskeleton to provide muscle support. Like other arachnids, the body of tarantulas is made up of two main parts, the front body or cephalothorax, and the rear body or abdomen. The front body and the rear body are connected by the pedicel or the front genitalia. This waist-shaped connecting piece is actually a part of the front body so that the rear body has a wide range of motion relative to the front body. The size of the tarantula can be as small as a bullet and as large as a dinner plate. Depending on the species, the body length of tarantulas varies from approximately 5 to 11 centimeters. The length of the legs is 8 to 30 centimeters. The leg extension is determined by measuring from the tip of the rear leg to the tip of the front leg on the other side. Some of the larger tarantula species can weigh more than 85 grams. Now a question comes that what is the biggest tarantula. The largest or the biggest of the tarantula spider is the giant bird-eating spider that is Theraphosa Blondi from Venezuela and Brazil, which apparently weighs 170 grams, its legs can reach a length of around 30 centimeter long and males are longer and stronger than females. The circumference of the females is larger. The fangs of this tarantula spider can reach up to four centimeters in length. 

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Tarantula Species

Most North American tarantula species are brown. Elsewhere, the species found show different colors like the Cyriopagopus lividus is cobalt blue in color, the Aphonopelmalookinganni species has black color with white stripes, the Eupalaestrus campestratus has yellow leg markings, the Chromatopelma cyaneopubescens species have metallic blue colored legs along with orange belly. These spiders’ natural habitats include savannas, grasslands, such as pampas, rainforests, deserts, shrubs, mountains, and cloud forests. They are usually classified as terrestrial types. Tarantulas are becoming increasingly popular as pets, and some species are readily available in captivity. 

Behavioural Characteristics of Tarantula

Some tarantulas feed primarily on trees while others hunt on or near the ground. All tarantulas can produce silk, tree species typically live in a silky tubular tent, while terrestrial species line their burrows with silk to stabilize cave walls and facilitate ascent and descent. Tarantulas primarily feed on large insects and other arthropods, such as centipedes, millipedes, and other spiders. Ambushes are their main method of capturing prey. Tarantulas have huge, powerful claws, with long chitinous teeth at the tips, which are well suited for killing other large arthropods. Larger tarantulas sometimes kill and eat small vertebrates such as lizards, mice, bats, birds, and small snakes. 

Appendices 

The tarantulas have eight legs, two chelates, their fangs, and tentacles are attached to the precursor of the body. The chelators are two two-piece appendages located directly below the eyes and directly in front of the mouth. The chelators contain toxic glands, which are ventilated through the fangs. The fangs are hollow extensions of chelating limbs that inject venom into prey or animals that tarantulas bite for defense, and are also used for chewing. These fangs are hinged together so they can extend downwards and outwards to prepare for a bite, or they can bend toward the chelate like the blade of a knife folds toward its handle. The claws of tarantulas completely contain venomous glands and muscles that surround them, which can forcibly inject venom into their prey. Pedipalpi are two six-sectioned appendages, connected to the precursor near the mouth and protruding on either side of the two chelated limbs. In most species of tarantula, the tentacles contain sharp serrated plates that are used to cut and grind food commonly called the coccyx or maxilla. Like other spiders, the terminal part of the male tentacles is part of their reproductive system. Male spiders spin a silky platform on the ground and release semen from glands in the upper body. They then insert the tentacles into the semen, absorbs the semen into the tentacles, and then insert the tentacles into the reproductive organs located in the female abdomen. The perimeter of the terminal segments of the tentacles of male tarantulas is larger than that of female tarantulas. Male tarantulas have special rows around the genital opening. The silk of the tarantula sperm web comes from these special rows. The tarantula has four pairs of legs and two additional pairs of appendages. Each leg has seven segments, which are hip, trochanter, femur, patella, tibia, tarsal bone, and anterior tarsal bone and claws. The end of each leg uses two or three retractable claws to clamp the climbing surface. Also at the end of each leg, surrounding the paw is a set of bristles, called scopula, which helps tarantulas to grasp better when climbing glass and other surfaces. The fifth pair is the tentacles, which aid in perception, grip, and mating in the case of adult males. The sixth pair of appendages are chelators and their attached fangs. When walking, the first and third legs on one side of the tarantula move simultaneously with the second and fourth legs on the other side of the body. Tarantula’s leg muscles make the legs bend at the joints, but to stretch the legs, tarantulas increase the pressure on the hemolymph that enters the legs. Tarantulas, like almost all other spiders, have their mainline at the end of the visual body. Unlike most spider species in the lower order Arachnida, the latter includes most existing spider species, most of which have six species, and tarantula species have two to four rows. These rows are flexible tubular structures from which spiders ooze silk. The tip of each row is called the rotating field. Each spinning yard is covered with as many as 100 spinning tubes, through which silk oozes out. When the silk is pulled from the row, the shear force causes the protein in the silk to crystallize, transforming it from a liquid to a solid. 

Digestive System 

The mouth of a tarantula lies beneath the chelates on the lower front of its precursor. The mouth is a short straw-like opening that you can only suck on, which means that everything should be liquid. Prey with a large number of solid parts, such as mice, must be crushed and ground or predigested, this is done by wrapping the prey with the digestive juice secreted by the openings of the cheeks. The digestive organ of a tarantula is a tube that runs through its entire body. In the precursor, the tube is wider and forms a suction stomach. When the powerful muscles of the stomach are contracted, the cross-section of the stomach increases, resulting in a strong sucking action, allowing the tarantula to suck its liquefied prey into the intestines through the mouth. Once the liquefied food enters the intestine, it breaks down into particles small enough to pass through the intestinal wall into the hemolymph, where it is distributed throughout the body. After feeding, the tarantula turns the leftovers into a small ball and throws them away. In glass containers, they are usually placed in the same corner. 

Nervous System 

The central nervous system of the tarantula is located in the lower part of the internal precursor. Tarantulas primarily perceive their environment through sensory organs called bristles or spines. Although the tarantula has eight eyes like most spiders, the sense of touch is its most acute sensation, in hunting it is based mainly on the vibrations emitted by the movement of the prey. Tarantula bristles are highly sensitive organs used to detect chemical characteristics, vibrations, wind direction, and possibly even sound. Tarantulas are also very sensitive to the presence of certain chemicals such as pheromones. The eyes are located above the chelating limbs in front of the forerunner. They are small, generally arranged in two rows of four. Most tarantulas can only see light, dark, and movement. Compared to terrestrial tarantulas, arboreal tarantulas generally have better vision. 

Respiratory System 

All types of tarantulas have two sets of book lungs. The first pair is located in the lower abdomen near the socket that connects the head and chest, and the second pair is slightly behind the abdomen. Air passes through the sides and front of the abdomen. The slit near the part enters the cavity. Each lung is made up of 15 or more folded sheets of tissue, arranged like pages in a book. These pieces of tissue are supplied by blood vessels. When air enters each lung, oxygen enters the bloodstream through the blood vessels in the lungs. These organs can also absorb the moisture they need from humid air. 

Circulatory System 

Tarantula blood is unique. The oxygen transporter that is copper hemocyanin is present, but not contained in blood cells, like mammalian red blood cells. Tarantula blood is not true blood, but a fluid called hemolymph. At least four types of blood cells or blood lymphocytes are known. The heart of a tarantula is a long, thin tube at the top of the eye socket. The heart is neurogenic rather than myogenic, so nerve cells rather than muscle cells activate and coordinate the heart. The heart pumps hemolymph to various parts of the body through open channels commonly called sinuses, rather than through the circulatory vascular system. If the exoskeleton ruptures, the loss of hemolymph will kill the tarantula unless the wound is so small that the hemolymph can dry out and close the wound. 

Sexual Dimorphism 

Some tarantula species exhibit significant sexual dimorphism. Compared to females, males tend to be smaller especially their abdomen, which looks narrow and may be darker in color, as in the Haplopelma lividum species. Mature male tarantulas may also have tibial hooks on their front legs, which are used to grasp the female's fangs during mating. Males tend to have longer legs than females. The sex of juvenile males can be determined by observing the cast molting of fusillade or giant spermatheca. Females have seminal vesicles, except for Sickius long bulb and Encyocratela olivacea. The life expectancy of males is much shorter than that of females because they die soon after they mature. Few people live to the last molting, which is unlikely to happen in natural habitats because they are susceptible to predation, but this has happened in captivity, although very rarely. Most males cannot survive molting because their emboli get stuck in the molting. The emboli are mature male sex organs. 

Life Cycle 

Like other spiders, tarantulas must shed their exoskeleton on a regular basis to grow. This process is called molting. As part of the maturation process, young tarantulas may do this several times a year, and adult tarantulas only shed their skins once a year or less, or faster, to replace lost limbs or lost bristles. Obviously, when the exoskeleton presents a deeper shadow, molting is imminent. If tarantulas have used bristle hair before, their baldness will change from pink to dark blue. During this period, tarantulas will also stop eating and become more lethargic. 

Tarantulas can live for many years. Most species take two to five years to reach adulthood, but some species can take up to 10 years to fully mature. After adulthood, males generally have only 1.0 to 1.5 years of life left, and they immediately begin looking for females to mate with. Male tarantulas rarely shed their skin again once they reach adulthood, but they may attempt to do so, usually during the molting process, getting stuck with their sex organs and dying in the process. Females continue to molt after maturity. Females are known to be 30-40 years old and can survive up to two years in water alone. Grammostola Rosea spiders are known to eat only once or twice a week and have been kept in captivity for up to 20 years. 

Reproduction 

After reaching sexual maturity, female tarantulas generally mate and lay eggs once a year, but this is not always the case. Like other spiders, the mechanism of sexual intercourse is very different from that of mammals. Once the male spider is mature and motivated to mate, it will weave a mat on a flat surface. The spider then rubs its abdomen on the surface of the mat and releases a large amount of semen in the process. They can then insert the tentacles that are short-legged appendages between the cheeks and forelegs into the semen pool. Pedipalps absorb semen and maintain its vitality until it finds a spouse. When a male spider detects the presence of a female spider, the two spiders exchange signals to confirm that they belong to the same species. These signals can also make women enter a state of acceptance. If the female is willing to accept, the male will approach her and insert his tentacles into an opening on the lower surface of her abdomen, the abdominal cavity. Once the semen is transferred to the receiving female, the male will quickly leave the scene before the female can regain her appetite. Although females may show some aggression after mating, males rarely become a meal. Females place 50 to 2000 eggs in filamentous oocysts and store them for six to eight weeks, depending on the species. During this period, the female will get very close to the oocyst and become more aggressive. In most species, females usually turn their oocysts, which is called brooding. This prevents the egg from deforming from sitting in one position for too long. After hatching, the young spiders remain in the nest for a period of time, and before dispersing they live on the remains of the yolk sac.