Goliath spider characteristics, habitat, reproduction, nutrition

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Anthony Golden

The goliath spider (Theraphosa blondi) is a "tarantula" of the suborder Migalomorphae and of the family Theraphosidae. It is considered the largest member of the order Araneae in the world. It is also considered the heaviest in the world, exceeding 150 grams or more, in animals kept in captivity..

These characteristics allow the Goliath spider, also known as the “aviary spider,” to catch birds for food. However, it should be noted that it is an uncommon practice, preferring other prey that are easier to hunt..

Goliath Spider (Theraphosa blondi) By Bernard DUPONT from FRANCE [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

This huge spider is typical of the humid jungles of South America, having a practically general diet due to the large number of items it feeds on..

The conservation status of this majestic spider has not been evaluated. However, there are several problems that endanger the stability of their populations. For example, environmental pressures such as illegal mining, deforestation of natural ecosystems for the establishment of agricultural activities, hunting for ethnic consumption and illegal trafficking for sale as pets..

Despite this, these spiders have a wide geographic distribution including several protected areas under the figure of national parks..

The gender Theraphosa included in the subfamily Theraphosinae, characterized by the presence of stinging hairs, currently includes three species: Theraphosa apophysis, Theraphosa blondi Y Theraphosa stirmi. The taxonomy of the group does not escape the morphological difficulties that encompass the entire suborder.

Article index

  • 1 General characteristics
    • 1.1 Action of the poison
    • 1.2 Interaction with humans
  • 2 Habitat and distribution
  • 3 Playback
    • 3.1 Ovoposition
  • 4 Nutrition
  • 5 Behavior
    • 5.1 Use of stinging hairs
  • 6 References

General characteristics

They are large spiders, with an extension of their legs of up to 30 centimeters, which makes them worthy of being considered the largest in the world. However, it should be noted that copies of Theraphosa apophysis with an extension of the legs greater than 30 centimeters.

In turn, the coloration of the Goliath spider is not the most striking among tarantulas, because it has cryptic habits with the jungle floor, with most of its surfaces being dark brown..

The stinging hairs located on the abdomen and some protruding hairs on the legs tend to be more reddish in color. This coloration becomes lighter as the spider is about to molt..

The cheliceral nails or "fangs" of this spider reach a length of up to two centimeters. Males and females are clearly distinguishable from each other. Males tend to have longer legs and a less robust body than females..

These spiders are capable of emitting sounds from the friction of stridulatory organs present in chelicerae, pedipalps and the first pair of legs. Despite having eight eyes, like most migalomorphs, their vision is poor and the latter is associated with their distinctly nocturnal habits..

The males of Theraphosa blondi lack tibial processes, so it does not immobilize the female's chelicerae during copulation.

Poison action

Although they are large spiders, their venom does not have biochemical characteristics that eventually endanger a person's life.

Among the effects caused by the venom, there is a strong localized pain in the affected area, attributed mainly to the damage caused by the entrance and the size of the chelicerae.

There is also swelling, redness and lack of sensitivity in the affected area. On the other hand, generalized sweating and dizziness may occur that can persist for several hours and even days..

The effect of the stinging hairs usually causes a more important reaction, especially if these specialized hairs enter the mucosa. The intensity of the effect of these hairs will also depend on the sensitivity of people to the toxins present in them.

Interaction with humans

Goliath spider in defensive position By Bernard DUPONT from FRANCE [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

Several indigenous ethnic groups use these spiders for food. The Venezuelan tribes Piaroa, Yekuana and Pemón hunt these spiders using active search techniques. Once the burrow of one of these tarantulas is located, they stimulate it until it emerges from its den, simulating the presence of a potential prey at the entrance of the same..

To do this, they use thin branches from the surrounding shrubby vegetation. At other times they usually dig until they find the spider. Once the spider is outside, it is caught and wrapped in palm leaves, keeping its legs immobilized. During the process, the spider is generally stimulated to rid itself of its stinging hairs..

Once they reach the villages, the spiders are placed in a bonfire until they are ready to be consumed. Other Amazonian indigenous ethnic groups such as the Yanomami also use these sources of food and correspond to an initiation of young hunters..

Habitat and distribution

This spider has a restricted distribution to the tropical rainforests present south of the Orinoco River in Venezuela, the northeast of Brazil, Suriname, Guyana and French Guiana. On the other hand, several localities in Colombia report the presence of this species.

These spiders are ground dwellers, indicating that they primarily occupy understory litter. They seek refuge in cavities present in the ground, under trunks in a state of decomposition, tree roots and also tend to occupy burrows abandoned by rodents or small mammals..

These spiders are adapted to living in conditions with high humidity, above 60%. In times of high rainfall, they move to higher areas, as their burrows are often flooded. The burrow, on the other hand, maintains very stable temperature conditions for much of the year..

The young are slightly more arboreal. So they can use microhabitats elevated from the ground.

Females do not tend to stray very far from their burrow to which they return after their period of nocturnal activity. Many females are observed for a long time at the entrance of the den waiting for the appearance of some prey. Males, on the other hand, after they reach maturity become wanderers from the jungle floor..

Reproduction

Females tend to be much longer than males, living up to 14 years in the wild and more than 20 years if they are kept in the best conditions in captivity. In contrast, males usually live for about three years on average, after sexual maturation..

Males actively seek out females during their reproductive life. Males are likely to detect chemical signals that the female leaves on silk threads near their dens. However, these aspects of chemical communication are poorly understood in spiders of the Theraphosidae family..

Additionally, communication through vibrational signals appears to be one of the main communication channels during courtship. Courtship of the male includes body vibrations, drumming of the pedipalps, and lifting of the first pairs of legs..

The reproductive period of these spiders is little known, however, other species such as Theraphosa apophysis they reproduce in late October and early November, when the rainy season ends.

Oviposition

Females lay the egg sac between two and three months after copulation. This sac can measure around 6 cm in diameter and be almost spherical.

The number of eggs in the sac can range from 40 to 80, which is relatively low compared to other smaller spiders. The young take about 40 days to develop on average. The mortality of small tarantulas during the first two molts after hatching is usually high..

The female actively protects the egg sac until the young emerge from it. Additionally, it uses the stinging hairs from the lateral regions of the abdomen to provide the egg sac with a second line of defense against some parasites such as dipteran larvae that can represent a problem..

Juvenile individual of Theraphosa blondi By Bernard DUPONT from FRANCE [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

Nutrition

Their diet is mainly based on small invertebrates. Most of its prey is included within insects, predating cockroaches, grasshoppers, lepidoptera and beetle larvae, among others. Other invertebrate animals that can consume are giant centipedes and earthworms up to 30 cm in length..

Among birds, they have been recorded consuming small birds trapped in mist nets for bats that settle near the range near their burrows. One of these birds was the common anthill Willisornis poecilinotus, very common in the understory of Brazilian rainforests.

Theraphosa blondi It has also been reported consuming terrestrial amphibians such as Rhinella marina in youth stadiums. Other species of frogs reported in the diet of the Goliath spider are the representatives of the genus Boana and a species of the Leptodactylidae family, specifically Leptodactylus knudseni.

Other amphibian reports include the Oscaecilia zweifeli. Also included in the diet of these spiders are various litter reptiles, such as Leptodeira annulata (Colubridae) and lizards of various groups.

On the other hand, this spider is capable of capturing various small-sized mammals such as rodents and small marsupials, some of which can reach the size and weight of this tarantula. In this video you can see how a specimen of a goliath spider catches a gecko:

Behaviour

In general, these spiders show shyness when they feel in danger. They generally flee to their lairs by noticing large vibrations through their special sensory organs present in their legs..

When disturbed, they can adopt various defensive strategies that are common among tarantulas of the subfamily Theraphosinae and with other spiders of large size or with some degree of aggressiveness..

They can generate warning stridulations against predators, which is a very particular form of acoustic aposematism of mygalomorphic spiders.

Additionally, it can carry out more aggressive behaviors that include standing up on its two pairs of hind legs and displaying its chelicerae. After this, if the interaction continues, they can carry out aggressive and quick dresses to drive away the source of danger..

Abdomen covered in stinging hairs of Goliath spider By Www.universoaracnido.com [CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)]

Use of stinging hairs

Another defensive strategy that these large spiders use is to shed the stinging hairs that they have on the lateral regions of their abdomen. These spiders, through their hind legs, rub the abdomen to release the stinging hairs that can generate strong allergic reactions..

Urticating hairs are type III, being filiform with closed edges and very small and light.These have a wide radius of action, favored in their dispersion by air currents..

They are more effective even when they enter the mucous membranes such as the eyes, nose and mouth, being quite effective in deterring predators..

References

  1. Araujo, Y., & Becerra, P. (2007). Diversity in invertebrates consumed by the Yanomami and Yekuana ethnic groups of Alto Orinoco, Venezuela. Interscience, 32(5), 318-323.
  2. Bertani, R., Fukushima, C. S., & Da Silva, P. I. (2008). Two new species of Pamphobeteus Pocock 1901 (Araneae: Mygalomorphae: Theraphosidae) from Brazil, with a new type of stridulatory organ. Zootaxa, 1826(1), 45-58.
  3. Boistel, R. and O. S. G. Pauwels. 2002a. Oscaecilia zweifeli (Zweifel's caecilian). Predation. Herpetological Review, 33: 120-121.
  4. Carvalho, W. D. D., Norris, D., & Michalski, F. (2016). Opportunistic predation of a Common Scale-backed Antbird (Willisornis poecilinotus) by a Goliath bird-eating spider (Theraphosa blondi) in the Eastern Brazilian Amazon. Studies on Neotropical Fauna and Environment, 51(3), 239-241.
  5. da Silva, F. D., Barros, R., de Almeida Cerqueira, V. L., Mattedi, C., Pontes, R. C., & Pereira, E. A. (2019). Predation on Leptodeira annulata (Linnaeus, 1758) (Squamata: Colubridae) by Theraphosa blondi (Latreille, 1804) (Araneae: Theraphosidae), in Amazon Forest, North of Brazil. Herpetology Notes, 12, 953-956.
  6. Menin, M., de Jesús Rodríguez, D., & de Azevedo, C. S. (2005). Predation on amphibians by spiders (Arachnida, Araneae) in the Neotropical region. Phyllomedusa: Journal of Herpetology, 4(1), 39-47.
  7. Nyffeler, M., Moor, H., & Foelix, R. F. (2001). Spiders feeding on earthworms. The Journal of Arachnology, 29(1), 119-125.
  8. Pérez-Miles, F., & Perafán, C. (2017). Behavior and Biology of Mygalomorphae. In Behavior and Ecology of Spiders (pp. 29-54). Springer, Cham.
  9. Saul-Gershenz, L. (1996). Laboratory culture techniques for the Goliath tarantula Theraphosa blondi (Latreille, 1804) and the Mexican red knee tarantula, Brachypelma smithi (Araneae: Theraphosidae). In American Zoo and Aquarium Association Regional Conference Proceedings (pp. 773-777).
  10. Striffler, B. F. (2005). Life history of Goliath Birdeaters-Theraphosa apophysis and Theraphosa blondi (Araneae, Theraphosidae, Theraphosinae). Journal of the British Tarantula Society, twenty-one, 26-33.

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