Spitting spiders are a family of

araneomorph The Araneomorphae (also called the Labidognatha or "true spiders") are an infraorder of spiders. They are distinguishable by chelicerae (fangs) that point diagonally forward and cross in a pinching action, in contrast to the Mygalomorphae (taran ...

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

s, the family Scytodidae, first described by

John Blackwall John Blackwall (20 January 1790 – 11 May 1881) was an English naturalist with a particular interest in spiders. Life Blackwall was born in Manchester on 20 January 1790. He lived at Hendre House near Llanrwst in north Wales from 1833 until ...

in 1864. It contains over 250

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

in five

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, of which ''

Scytodes ''Scytodes'' is a genus of Scytodidae, spitting spiders that occur all around the world, with the most widely distributed species being ''Scytodes thoracica'', originally having a Palearctic realm, palearctic distribution but has since been intr ...

'' is the best-known.

Description

Scytodidae spiders are

haplogyne The Haplogynae or haplogynes are one of the two main groups into which araneomorph spiders have traditionally been divided, the other being the Entelegynae. Morphological phylogenetic studies suggested that the Haplogynae formed a clade; more rece ...

, meaning they lack hardened female genitalia. They have six eyes, like most spiders in this group, arranged in three pairs. They possess long legs and a dome-shaped

cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...

, and are usually yellow or light brown with black spots or marks. Their domed head and three eye groups tend to resemble a human skull, giving them the occasional common name "skull spiders".

Hunting technique

Scytodidae catch their prey by spitting a fluid that congeals on contact into a

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

and sticky mass. The fluid contains both venom and

spider silk Spider silk is a protein fibre or silk spun by spiders. Spiders use silk to make webs or other structures that function as adhesive traps to catch prey, to entangle and restrain prey before biting, to transmit tactile information, or as nest ...

in liquid form, though it is produced in venom glands in the

chelicerae The chelicerae () are the arthropod mouthparts, mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated ...

. The venom-laced silk both immobilizes and envenoms prey such as

silverfish The silverfish (''Lepisma saccharinum'') is a species of small, primitive, wingless insect in the order Zygentoma (formerly Thysanura). Its common name derives from the insect's silvery light grey colour, combined with the fish-like appearanc ...

. In high-speed footage the spiders can be observed swaying from side to side as they "spit", catching the prey in a criss-crossed "Z" pattern; it is criss-crossed because each of the

emits half of the pattern. The spider usually strikes from a distance of and the entire attack sequence only lasts 1/700th of a second. After making the capture, the spider typically bites the prey with venomous effect, and wraps it in the normal spider fashion with silk from the spinnerets.

Pre social behaviour

Some species exhibit

presocial Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...

behaviour, in which mature spiders live together and assist the young with food.

Genera

, the

World Spider Catalog The World Spider Catalog (WSC) is an online searchable database concerned with spider taxonomy. It aims to list all accepted families, genera and species, as well as provide access to the related taxonomic literature. The WSC began as a series of ...

accepts the following genera: *''

Dictis ''Dictis'' is a genus of spitting spiders that was first described by Ludwig Carl Christian Koch in 1872. Species it contains seven species, found in Asia, Oceania, North America and Seychelles: *'' Dictis edwardsi'' Barrion, Barrion-Dupo & Heo ...

'' L. Koch, 1872 — Asia, Oceania, North America and Seychelles *''

Scyloxes ''Scyloxes'' is a genus of Tajikistani spitting spiders containing three species. It was first described by P. M. Dunin in 1992 and remained a monotypic genus until 2022, when Zamani et al. moved two species into the genus, ''S. magna'' and ''S. ...

'' Dunin, 1992 — Tajikistan *''

'' Latreille, 1804 — South America, Africa, Asia, North America, Caribbean, Central America, Oceania, Spain *''

Stedocys ''Stedocys'' is a genus of Asian spitting spiders that was first described by H. Ono in 1995. Species it contains thirteen species, found in Asia: * '' S. amamiensis'' Suguro, 2019 — Japan * '' S. gaolingensis'' Wu & Li, 2017 — China * '' S ...

'' Ono, 1995 — China, Malaysia, Thailand

References

External links