Wednesday, 3 March 2010

Red Kneed Tarantula

Although there are many species of tarantula, the dffierent forms generally share similar characteristics. Their large, hairy bodies are often strikingly marked, and some species have become popular as pets. Collection of the red-kneed tarantula has put the wild population at risk. The red-kneed tarantula is arguably the most popular of all pet tarantulas, and people have been collecting specimens since the 1970s.
First discovered in 1888, the spider was soon recognized as having potential as a pet. It was also used to heighten tension in films such as Raiders of the Lost Ark. Such publicity encouraged collection, and tarantulas were sold in pet stores for many years. The red-kneed tarantula is found mainly in Mexico and Central America. Its natural habitat is scrubland and desert that provide temperatures of 70-90°F (20-30′C) and humidity of about 60 percent. The spider is found near cacti and bushes, and among logs, rocks, and other debris. It digs burrows in the ground that it lines with spider silk. For most of the time the spider is relatively docile. However, a threatened red-kneed tarantula will rear up and display the red bristles on its body. As a defensive measure it will flick off urticating (irritant) hairs in the direction of its predator. The hairs are microscopically barbed (having tiny hooks) and can be irritating to the skin and lungs, causing a form of urticaria (an allergic disorder). Serious damage can occur if any hairs become embedded in the eye. Although most people are not seriously affected by the spider’s venom, some are allergic to it and can have a strong adverse reaction.

Intriguing Habits

The red-kneed tarantula has a typical spider form, including a pair of fangs (chelicerae) that it uses to stab prey and inject venom. Pedipalps-small appendages near the mouth-have a number of functions, including handling prey. The spiders have poor vision, but sensory structures on the end of the legs allow them to smell, taste, and feel. The tarantula does not spin a web to catch its food; insects, small amphibians, and sometimes mice are actively hunted at night. The prey is subdued with venom and then flooded with digestive juices. Tarantulas are unable to digest food internally, so the digested “soup” of nutritionally valuable parts of the prey are sucked back by the spider. Males are often eaten by their mates after mating. When mature, a male spider spins a tubular web in which he deposits sperm. He then draws the sperm up into a special receptacle in his pedipalps. When mating is about to start, the male makes courtship signals, which help ensure that the female does not mistake him for prey. He uses tibia) spurs (sharp projections) to grip the female’s fangs while placing sperm in the female’s reproductive tract.

Black Market

Although red-kneed tarantulas are relatively easy to keep, they are not easy to breed in captivity. The females live for a long time, often up to 20 years in captivity, but their reproductive rate tends to be slow. As a result of their popularity with collectors and the tarantula’s vulnerability to habitat change, the species has become seriously threatened. Populations could not sustain the demands of the pet trade, and the wild spiders are now difficult to find. Mexico has prohibited their capture and export, but a black market still exists: Smugglers have been caught trying to take them out of their native countries.

Red-kneed tarantula Euathlus smithi

* Family: Theraphovdae
* World population: Unknown
* Distribution: Central America and Mexico
* Habitat: Scrubland and desert
* Size: Length: up to 2.5 in (6.4 cm); leg span: up to 5 in (12.7 cm)
* Form: Cephalothorax (arachnid with joined head and thorax); opisthosoma (abdomen) with 4 pairs of strikingly patterned legs; claws for gripping. Eight eyes on head allow all-round (but poor) vision. Males have thin body and long legs; mature males have tibia) spurs (sharp projections) on pedipalps (appendages on cephalothorax) to grip female’s fangs during mating
* Diet: Insects; also small animals such as lizards and mice
* Breeding: Female produces up to 700 young a year (often fewer). Eggs wrapped in silk and carried by mother. Spiderlings guarded for several weeks after hatching. Life span of males 7-8 years; females 20-25 years in captivity
* Related endangered species: None

1 коментара:

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