Auntie Spider

Kelly’s Field Notes

Common Name: Spitting Spider  

Order: Araneae

Family: Scytodidae

Genus: There are four genera of spitting spider (Dictis, Scyloxes, Scytodes, and Stedocys)

Species: There are 239 species of spitting spider worldwide, 9 of which live in the U.S. (Bug Guide, 2022;The University of Queensland Australia, 2017).

Notable species:

• Common spitting spider (Scytodes thoracica) - the most common species, found throughout the eastern U.S and parts of the northwestern U.S., Europe, Northern Africa, India, Australia, and New Zealand.

Description: 

Spitting spiders have six eyes arranged in three pairs. We’ve discussed this in previous episodes, but you can tell what family a spider belongs to by its unique eye arrangement! They also have a dome-shaped cephalothorax, long, thin legs and are often a pale yellow in color with darker brown markings. Their very long legs cause them to walk rather slowly when compared to other spiders.

Spitting spiders are generally small bodied (body length ~3–6 mm or 0.12-0.24 inches in S. thoracica, for example) and are often found indoors or in hidden crevices (walls, under stones, corners, etc.) (The University of Queensland Australia, 2017). They are more active at night. 

Some spitting spiders do spin webs, but most are active hunters engaging in a series of movements as they hunt: tapping, spitting, biting, wrapping, and feeding.  Spitting spiders have terrible eyesight, so to orient themselves to spit they begin by tapping their two front limbs around and on their prey when they’ve located something tasty. Then they spit on the prey, subduing it and sticking it to the ground, before biting it to inject venom. The “spit” comes from the spider’s fangs and is always deployed in a zig-zag manner. By zig-zagging the strands overlap each other forming a strong net. Immediately after the bite they wrap their prey in silk then feed when it is secured. Spitting spiders rarely choose prey that is their size or larger (Nentwig, 1985). Interestingly, spitting spiders are also known to scavenge already dead prey, foregoing the spitting of glue or silk in the process (Vetter, 2013). If approached by a predator they will employ the same spitting maneuver. There is currently some controversy over whether or not spitting spider silk is laced with venom given it comes from the venom glands.

Spitting:

Spitting spiders are not the only family of spiders to spit on predators to deter them. Green lynx spiders (Peucetia viridans), family Oxyopidae, spray venom from their fangs but do not also spray silk or “glue” (Fink, 1984).

Life Cycle: 

Spitting spider females produce between 20-30 eggs, which they wrap up in silk and carry either in their chelicerae, protecting the eggs until they hatch. Spitting spiders engage in “periodic-social” behavior. The female will guard and even bring food to her spiderlings until they reach their fourth instar. After the fourth instar there is a risk of cannibalization between siblings. Siblings, before the fifth instar, will also cooperatively spit on larger prey to subdue and feed on it together (Li et al., 1999).

Super Powers:

• Web Spit - spitting spiders spit venom, silk, and a glue-like substance in a zig-zag pattern to subdue prey. The spit happens very rapidly, taking 30 ms to deploy with a velocity of 28.8 m/s (Suter and Stratton, 2009). The spit can travel about 10 mm or more in distance (British Arachnological Society, 2025).

• Friendly? - spitting spiders display a degree of sociality uncommon to spiders.

• Usual spider powers - see our past episodes!

Spitting Spiders and Humans:

Spitting spider venom is currently being used for medical research. Venom peptides have potential as the basis of new types of medication. Because spider venom peptides target ion channels in the nervous system they can be used to activate or inhibit them to treat humans dealing with chronic pain and autoimmune disorders. Currently, 3 out of 47 spitting spider peptides have been tested. So far none are medically significant but researchers will continue to test the remaining peptides (Ariki et al., 2016). Venoms from about 100 spider species from 47,000 known species have been studied, mostly from tarantulas given how easily available they are through the pet trade. Tarantula venom peptides make up 450 of 1,426 known spider venom peptides (The University of Queensland Australia, 2017).

References:

Ariki, Nathanial K., et al. "Characterization of three venom peptides from the spitting spider Scytodes thoracica." PloS one 11.5 (2016): e0156291.

“Family Scytodidae - Spitting Spiders.” Bugguide.net, 2022, bugguide.net/node/view/3345. Accessed 28 Nov. 2025.

Fink, Linda S. "Venom spitting by the green lynx spider, Peucetia viridans (Araneae, Oxyopidae)." The Journal of Arachnology 12.3 (1984): 372-373.

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Li, Daiqin, Robert R. Jackson, and Alberto T. Barrion. "Parental and predatory behaviour of Scytodes sp., an araneophagic spitting spider (Araneae: Scytodidae) from the Philippines." Journal of Zoology 247.3 (1999): 293-310.

Nentwig, Wolfgang. "Feeding ecology of the tropical spitting spider Scytodes longipes (Araneae, Scytodidae)." Oecologia 65.2 (1985): 284-288.

“Spitting Spiders - Nature’s Strangest Hunters.” Institute for Molecular Bioscience, The University of Queensland Australia, 2017, imb.uq.edu.au/article/2017/11/spitting-spiders-natures-strangest-hunters.

‌Suter, Robert B., and Gail E. Stratton. "Spitting performance parameters and their biomechanical implications in the spitting spider, Scytodes thoracica." Journal of Insect Science 9.1 (2009): 62.

British Arachnological Society. “Summary for Scytodes Thoracica (Araneae).” Britishspiders.org.uk, 2025, srs.britishspiders.org.uk/portal.php/p/Summary/s/Scytodes%2Bthoracica. Accessed 28 Nov. 2025.

‌Vetter, Richard S. "Scavenging behavior in spitting spiders, Scytodes (Araneae: Scytodidae)." The Journal of Arachnology 41.3 (2013): 392-394.