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Theridiidae

life science Maturity 5-7 Next article →

Theridiidae is a massive family of araneomorph spiders. They are known by several common names. People often call them tangle-web spiders, cobweb spiders, or comb-footed spiders.

Theridula angula at Kadavoor
Theridula angula at Kadavoor

This family is incredibly diverse and lives all over the globe. It is the most common group of arthropods found in human homes worldwide. Scientists first described this family in 1833. A researcher named Carl Jakob Sundevall provided the first formal description. Today, we know the family includes around 3,000 different species. These species are organized into 128 different genera.

These spiders have unique biological traits that set them apart. They are classified as entelegyne spiders. This means the females possess a specific genital plate. They are also ecribellate spiders. This term describes how they spin sticky capture silk instead of woolly silk.

Coscinida.japonica.female.-.tanikawa
Coscinida.japonica.female.-.tanikawa

To manage this silk, they use a specialized tool. They have a comb of serrated bristles called setae. These bristles are located on the tarsus, which is the end of the fourth leg. This physical structure is a key feature of the family.

Web building is a central part of their survival. Many species build tangle space webs. These webs can be very diverse in form. Some spiders build gumfoot-webs to catch prey. These webs use frame lines to anchor to the surroundings. They also use support threads that contain viscid silk.

Enoplognatha.abrupta.female.-.tanikawa
Enoplognatha.abrupta.female.-.tanikawa

Some webs have a central retreat, known as the Achaearanea-type. Others have a peripheral retreat, known as the Latrodectus-type. Some webs contain viscid silk, while others are sheet-like. The Coleosoma-type web is an example of a sheet-like web without viscid silk.

Some members of this family have even more complex lifestyles. The Argyrodinae are a group of kleptoparasitic spiders. This includes the genera Argyrodes, Faiditus, and Neospintharus. These spiders live inside the webs of much larger spiders. They act as thieves by stealing small prey caught in the host's web.

Dipoena.martinae.female.-.tanikawa
Dipoena.martinae.female.-.tanikawa

They may also consume the silk from the host's web. In some cases, they even attack and eat the host spider itself.

Because of their unique traits, many theridiids are model organisms. Model organisms are species used by scientists to study specific biological processes. The widow spiders are medically important for research. Scientists study their venom and how it manifests clinically in the body.

Black Widow Spider 07-04-20
Black Widow Spider 07-04-20

Other species are used to study spider silk and sexual biology. This includes the study of sexual cannibalism. The genus Anelosimus is used to study sociality. Some Anelosimus species are solitary, while others are permanently social. Because social species are highly inbred, they also help study inbreeding.

Genetic diversity is also studied within this family. The Hawaiian spider, Theridion grallator, is a famous example. It is often called the "happyface" spider. This is because certain color morphs have patterns on their yellow bodies. These patterns look like a smiley face or a grinning clown face.

Theridion impressum 01
Theridion impressum 01

Scientists use this spider to understand the genetic basis of color polymorphism. Polymorphism refers to when a single species has many different physical forms.

Taxonomy, the science of naming and classifying life, shows the family's scale. The largest genus is Theridion, which contains over 600 species. However, this genus is not monophyletic, meaning it does not share a single common ancestor. Another large genus is Parasteatoda. This genus includes the North American common house spider.

The family's vast number of genera, such as Latrodectus and Argyrodes, highlights its complexity. These spiders represent a vital part of global ecosystems and scientific research.

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🖼️ Images & Media (8)
File:Chrysso.pulcherrima.male.-.tanikawa.jpg
Chrysso.pulcherrima.male.-.tanikawa.jpg
File:Coscinida.japonica.female.-.tanikawa.jpg
Coscinida.japonica.female.-.tanikawa.jpg
File:Dipoena.martinae.female.-.tanikawa.jpg
Dipoena.martinae.female.-.tanikawa.jpg
File:Enoplognatha.abrupta.female.-.tanikawa.jpg
Enoplognatha.abrupta.female.-.tanikawa.jpg
File:Episinus.nubilus.male.-.tanikawa.jpg
Episinus.nubilus.male.-.tanikawa.jpg
File:Black Widow Spider 07-04-20.jpg
Black Widow Spider 07-04-20.jpg
File:Theridion impressum 01.JPG
Theridion impressum 01.JPG
File:Theridula angula at Kadavoor.jpg
Theridula angula at Kadavoor.jpg
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