Spitting Spider (Scytodidae) is a small family of spiders that includes 5 genera and 150 species. These are small and seemingly unremarkable spiders, however, they have one interesting feature – during the hunt, they “spit” cobwebs into their prey and thus entwine it. Thanks to this unusual way of hunting, these spiders got their name – “spitters”.
Representatives of the genus Scytodes are predominantly tropical or subtropical spiders. However, spitting spiders are scattered throughout the Nearctic, Palaearctic, and Neotropical regions. This species is commonly found in the eastern United States, as well as the UK, Sweden, and other European countries. Spitting Spiders have been found in Japan and Argentina. The presence of this species in more severe conditions is explained by the presence of warm houses and buildings in which these spiders have adapted to inhabit. Spitting Spiders are found in temperate forests. Most often found in dark corners of living quarters, basements, closets, and other areas.
Spitting Spiders have long, thin, and bare (hairless) limbs, except for short sensory setae scattered throughout the body. These spiders are also easily identified by the oversized cephalothorax (prosoma), which tilts up behind. The abdomen has about the same round shape as the cephalothorax and slopes downward and is only slightly smaller in size than the cephalothorax. Like all spiders, these two parts of the body (segments) are separated by a thin leg – the “waist”. Large, well-developed venom glands are located in front of the cephalothorax. These glands are divided into two parts: the smaller, front part, which contains the venom, and the large posterior compartment, which contains the gooey substance.
Spitting Spiders secrete a sticky secret, which is a mixture of two substances, and is excreted in a condensed form from the chelicerae, and cannot be excreted separately. This species of spider lacks a silk-secreting organ (cribellum). Breathing is tracheal. The chitinous cover of a pale yellow body with black speckled markings on the cephalothorax, this pattern slightly resembles a lyre. The limbs gradually taper towards the bottom in comparison with the thickness at the exit from the body. They are long with black stripes. On the front of the head, there are mandibles under the eyes. Males and females have different body sizes: 3.5-4 mm in length reach the male, and females – from 4-5.5 mm.
Spitting Spiders live solitary and only meet each other during mating. Most contact occurs during the warmer months (August), but these spiders can mate outside a certain season if they live in heated rooms These spiders are hunters, so males approach with caution, otherwise, they can be mistaken for prey. They release pheromones, which are found in special hairs that cover the pedipalps and the first pair of legs. Females determine the presence of a male by odorous substances.
Upon meeting with a female, the male moves the sperm to the female’s genitals, where the sperm is stored for several months until the eggs are fertilized. Compared to other arachnids, spitting spiders lay relatively few eggs (20-35 eggs per cocoon) and 2-3 cocoons that the female builds each year. This type of spider takes care of the offspring, females wear a cocoon with eggs under the abdomen or in chelicerae for 2-3 weeks, and then the spiders that appear remain with the females until their first molt. The growth rate of young spiders, and therefore the rate of molting, is closely related to the availability of prey. After molting, young spiders will disperse to different places to live a secluded life, reaching maturity after 5-7 molts.
Compared to some spider species, Spitting Spiders have a relatively long habitat in the environment, they do not die immediately after mating. Males live 1.5-2 years, and females 2-4 years. Spitting Spiders mate several times and then die from starvation or predation, most often males, when they move in search of a female.
Features of Behavior
Spitting Spiders are predominantly nocturnal. They roam alone, actively hunt for their prey, but since they have long, thin legs, they move too slowly. Their vision is weak, so spiders often explore the environment with their forelimbs, which are covered with sensory bristles.
Noticing the approaching prey, the spider attracts its attention, slowly taps with its front legs until the victim is in the center between them. Then he spits out a sticky, poisonous substance on the prey, covering 5-17 parallel, intersecting stripes. The secret is released at a speed of up to 28 meters per second, while the spider lifts its chelicerae and moves them, covering the victim with layers of cobwebs. Then the spider quickly approaches its prey, using the first and second pairs of legs, entangling the prey even more. The poisonous glue has a paralyzing effect, and as soon as it dries, the spider bites the victim, injecting poison inside to dissolve the internal organs. After the work is done, the Spitting Spider thoroughly cleans the first two pairs of limbs from the remaining glue, then brings the prey to the chelicera with its pedipalps. The spider holds the victim with a third pair of limbs and wraps it in a web. Now it slowly sucks out dissolved tissue. These Spitting Spiders also use poisonous “spitting” as a protective measure against other spiders or other predators. They move too slowly to flee and defend themselves in this manner.
Spitting Spiders are active nocturnal wanderers, but they do not build webs. They are insectivorous and live indoors, mainly eating insects and other arthropods such as moths, flies, other spiders, and household insects (bed bugs). When they live in nature, they also hunt insects, destroy black citrus aphids, citrus mealybugs, Filipino grasshoppers, and butterflies, consume mosquitoes (blood-sucking insects). Many food items are significantly larger than Spitting Spiders. Female spiders can also occasionally consume insect eggs.
- These spiders are not dangerous to humans, do not weave grandiose networks of traps, and are unremarkable outwardly. Still, they have one feature – during the hunt, they “spit” into their prey.
- Spitting Spiders live in both warm tropical and temperate regions. In the tropics, they live under stones, on plants, and in temperate latitudes in human houses, where it is warm.
- Unlike other spiders, the spider glands in Spitting Spiders are located not only in the abdomen but also in the cephalothorax. This is part of the poisonous glands that have turned into arachnoid. The abdominal glands, in turn, are poorly developed but secrete a web of 2 species, of which the Spitting Spider creates a simple web-house for itself.
- In most species of this family of spiders, the spitting web is non-venomous, but in the Scytodidae, the spider glands in the cephalothorax connect with the venomous ones, as a result of which the victim from the spitting web is not only immobilized but also gradually dies. Then the spider approaches the victim, injects digestive juices, and drags it to its nest, where it calmly begins to eat.
- These spiders are completely harmless to humans since they are very tiny, no more than 6 millimeters in length (this is without legs). But tropical species can be larger – about 1 centimeter. They are all brown and decorated with a pattern of dark spots. In some species of Spitting Spiders, the length of the legs exceeds the length of the body by almost 4-5 times. And they have only 6 eyes, instead of the usual 8.
- Most often they prey on small soft-bodied insects: tropical inhabitants – on insects and other spiders, and in temperate latitudes – on various midges and flies. Why soft-bodied? First, this is especially important for species with poisonous webs. The chitinous cover of the victim prevents the penetration of poison into the body of the prey. And, secondly, shelling at the “armored” prey is an unsafe activity for a spider, since the web may not work, but it will attract attention to itself.
- Spitting Spiders go fishing at night when everyone is asleep. He slowly goes around his possessions. Having found future prey, the spider carefully stretches out one front leg, as if estimating the approximate distance to it. After a short “counting”, he spits out two sticky threads on the victim. The whole action takes literally 1/600 of a second. During this time, the web manages to take a zigzag shape in the air, freeze a little and cover the victim. The spider “spits” for a reason, but aims at the legs and wings of the insect. To catch a medium fly, he has to make about 8 such spikes of a web, although it all depends on the size of the victim. Then he drags the prey to his nest, where he deals with it.
- The wedding period for these spiders begins in March and lasts until October. Males are tolerant to each other at this time, without fights.
- After mating, the male can be calm, he will not be eaten by a bloodthirsty female. And in the meantime, she goes to spin a brood net. She fixes it on the abdomen and lays about 25 rather large eggs there.
- For two weeks she walks with this large load until small spiders hatch inside the cocoon. They sit there until mom breaks the cocoon and lets the kids out. After another 10 days, they have their first molt. Together with their mother, they live up to their third molt, and there they already start free-swimming.
- Spitting Spiders live for about 4-5 years, after which they die of old age if they have not been killed earlier.