''Latrodectus indistinctus'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...

in the family

Theridiidae Theridiidae, also known as the tangle-web spiders, cobweb spiders and comb-footed spiders, is a large family of Araneomorphae, araneomorph spiders first described by Carl Jakob Sundevall in 1833. This diverse, globally distributed family includes ...

, found in

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

and

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. It is one of six species of ''

Latrodectus ''Latrodectus'' is a broadly distributed genus of spiders with several species that are commonly known as the true widows. This group is composed of those often loosely called black widow spiders, brown widow spiders, and similar spiders. Howeve ...

'' found in southern Africa, four of which, including ''L. indistinctus'', are known as black button or black widow spiders. Like all ''Latrodectus'' species, ''L. indistinctus'' has a

neurotoxic Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specificall ...

venom. It acts on nerve endings, causing the very unpleasant symptoms of

latrodectism Latrodectism () is the illness caused by the bite of ''Latrodectus'' spiders (the black widow spider and related species). Pain, muscle rigidity, vomiting, and sweating are the symptoms of latrodectism. There are several spider species all named b ...

when humans are bitten.

Description and behavior

Like all spiders in the genus ''Latrodectus'', females are larger than males. Females range from 7 to 16 mm, and the males 2.5 to 5 mm. In maturity, most retain at least short red stripes radiating upward from the tip of the dorsal abdomen. Like many black widows, it is not aggressive. Its defense method when it feels threatened is to drop to the ground and play dead. Their egg sacks are usually hung in bush vegetation, where prey, which includes insects and arthropods, is available nearby. Females will occasionally attack to defend their eggs.

Habitat

Its distribution is limited in Namibia and South Africa. Found in habitats such as tangled bushes, uncut grass, tall vegetation in dry places, agricultural areas and forests.

Venom

They have neurotoxins known as

latrotoxin A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus ''Latrodectus'' (widow spiders) as well as at least one species of another genus in the same family, '' Steatoda nobilis''. Latrotoxins are the main activ ...

s. Within 15 minutes after a bite there is intense pain, burning sensation, and swelling. Systemic effects, such as intense muscle pain and cramps, can occur hour later. Other symptoms include anxiety, slurred speech, feeling sick, headaches, sweating, and fever. Rapid pulse, increased blood pressure, and tightness in the chest together with difficulty breathing are important symptoms, which are usually more dangerous for children and elderly people with cardiovascular and respiratory diseases. In a case that occurred in 2016, in South Africa, in a 38-year-old man reported symptoms such as intense muscle pain, erythema, stiffness at the location of the bite that radiated to the trunk, arm and neck, muscle spasms, and mild tachycardia.

References

{{Taxonbar, from=Q1985509 indistinctus Spiders of Africa Arthropods of Namibia Spiders of South Africa Spiders described in 1904 Taxa named by Octavius Pickard-Cambridge