A net-casting spider, also called an ogre-faced spider, is a slender, stick-like nocturnal spider of the genus Deinopis that hangs head-down at night holding a small stretchy silk net in its front legs and throws that net over passing insects. The net-casting spider is found in warm, humid parts of the world, including gardens, scrub and forest edges in India, and it is almost invisible by day because it looks like a dry twig.
Instead of waiting in a fixed web, the net-casting spider acts as an active ambush hunter, using enormous night-vision eyes to judge the right moment to strike. This article explains what the net-casting spider is, how it builds and uses its net, what it eats, whether it is dangerous and how it lives its life.
| Quick Facts | Details |
|---|---|
| Scientific name and family | Genus Deinopis, family Deinopidae (net-casting or ogre-faced spiders) |
| Size | Body roughly 1.5 to 2.5 cm long; females are larger than males, and the long legs make the spider look longer |
| Habitat in India | Gardens, scrub, shrubs and forest edges in warm and humid regions, including the Western Ghats and the north-east |
| Diet | Small night-flying and ground-walking insects such as moths, beetles, crickets and mosquitoes |
| Life cycle | The female hangs a silk egg sac among vegetation; spiderlings hatch and grow through moults to maturity within about a year |
| Activity | Nocturnal; hides motionless during the day, hunts at night |
| Ecological role | Predator of night-active insects, including some garden pests |
| Notable features | Two huge forward-facing eyes, a net of woolly cribellate silk, and a stick-like camouflage |
Key Takeaways
- The net-casting spider is a nocturnal spider of the genus Deinopis, family Deinopidae, that catches prey by throwing a small silk net.
- The net-casting spider is also called the ogre-faced spider because of two very large eyes that give its face a monstrous look.
- The two large central eyes of the net-casting spider are extremely sensitive to light, which lets it hunt on dark nights.
- The net-casting spider spins a new net each night from woolly cribellate silk and usually eats the old net before dawn.
- The net-casting spider is camouflaged as a twig by day and is harmless to humans in practice.
- The net-casting spider can strike forwards at ground prey and backwards at flying insects overhead.
What is a net-casting spider?
A net-casting spider is a spider of the family Deinopidae that does not wait in a web but holds a small rectangular net between its front legs and flings it over prey. The family is placed among the cribellate spiders, which produce a special woolly, sticky silk without glue droplets.
The common name describes its behaviour, and the alternative name, ogre-faced spider, comes from the pair of very large eyes that dominate its face. Taxonomically there are two genera in the family, Deinopis and Menneus, and Deinopis is the one most often meant in discussions of net-casting spiders. Species of the family occur in the tropics and subtropics of Asia, Africa, Australia and the Americas.
The spider is long, thin and brown or grey, with a narrow abdomen and four long front legs that are held out in front. When it stays still on a twig, it can look like a bit of dried grass, and many people never notice one even in their own garden.
Why is the net-casting spider called the ogre-faced spider?
The net-casting spider is called the ogre-faced spider because its face is dominated by two enormous, dark, forward-looking eyes that give it a staring, ogre-like expression. These are not the usual small eyes of a typical spider and are among the largest eyes of any spider relative to body size.
Like most spiders, the net-casting spider has eight eyes, arranged in three rows. The two large central eyes in the middle row, known as the posterior median eyes, are the ones that give the “ogre” look. They are built to gather as much light as possible and let the spider see movement on a moonless night. The other six eyes are much smaller and are used in less demanding ways.
Researchers have also noted that the structure of these eyes is renewed regularly. Light-gathering membranes are broken down and rebuilt on a daily cycle, which makes the spider especially sensitive to light at nightfall when hunting starts.
How does the net-casting spider catch its prey?
The net-casting spider catches prey by hanging head-down from a few silk lines, holding a stretchy net spread out by its front four legs, and stretching the net over any insect that comes within range. The spider does not chase prey; it waits in position and strikes with a very rapid movement.
Setting up for the night
At dusk the spider builds a framework of a few dry lines among twigs or leaves, then weaves a small net of cribellate silk. The net is rectangular and is held loosely between the four front legs. The spider then hangs near the ground or just above the leaf litter, with its body angled down and its great eyes pointed at the space beneath.
The forward strike
If an insect walks on the ground below, the spider extends its legs and stretches the net, swooping it down over the target. The net is elastic and clings to the prey’s body, so the insect becomes tangled when it struggles.
The backward strike
The net-casting spider can also swing its net backwards over its own body to catch flying insects that pass behind or above it. This technique is useful for catching moths and other flying prey, and it is one reason the spider is such a specialised hunter.
Wrapping and eating
After the catch, the spider bites the prey to subdue it, wraps it in additional silk if needed, and feeds by injecting digestive fluids and sucking up the liquefied contents. After the meal the net is reset or rebuilt.
What does the net-casting spider eat?
The net-casting spider eats small insects, mainly those that are active at night, such as moths, beetles, crickets, small flies and mosquitoes. It also takes other small arthropods that pass beneath its perch, such as ants or small spiders.
Because it feeds on insects that are active in darkness, the spider can help in controlling garden pests, but it works on a very small scale and is not a substitute for pest management. As an ambush predator it needs far less food than active hunters, and it can go several days without eating if prey are scarce.
Studies of related species have suggested that the net-casting spider may also use sound. In experiments, some Deinopis spiders responded to the sound of flying insects behind them and swung their nets backwards, which indicates that the spider does not depend on eyesight alone to catch flying prey.
What does the net of a net-casting spider look like?
The net of a net-casting spider is a small, woolly, rectangular patch of silk, usually only a few centimetres across, that can be stretched to several times its resting size. It is made of cribellate silk, which has very fine fibres that form a fuzzy, comb-like mass.
Cribellate silk does not rely on sticky glue. Instead, the spider combs the fine fibres with a row of bristles on the hind legs, called the calamistrum, to create a mass of very fine loops. These loops catch on the tiny hairs and spines on an insect’s body, much like Velcro. The fibres are also thought to be able to carry a little electrostatic charge, which can help them cling to prey.
The net is fragile and is usually used for one night. Before sunrise the spider commonly eats the old net, recycling the protein, and then weaves a new one on the next evening. This regular rebuilding keeps the silk fresh and sticky.
Where is the net-casting spider found in India?
The net-casting spider is found in India in warm, humid habitats such as the Western Ghats, the north-eastern states, the Andaman and Nicobar Islands and other forested or garden areas with plenty of shrubs. It prefers sheltered spots with leaf litter, low branches and dense vegetation.
Several species of Deinopis have been recorded in South and South-East Asia, and the spider is seen by naturalists who walk through gardens and forest trails with torches at night. It is relatively rare in dry, open regions. Even where it is common, it is easy to overlook because it holds still and lacks bright colours.
Typical places to look include:
- Low shrubs and branches in forest edges and plantations.
- Garden hedges, bushes and dense plantings.
- Undergrowth near streams in humid forests.
- Leaf litter and bark crevices, where the spider rests by day.
How does the net-casting spider hide during the day?
The net-casting spider hides during the day by pulling its long legs together in a line along its body and staying completely still on a dry twig, stem or grass blade so that it resembles a piece of plant debris. This mimicry protects the spider from birds, lizards and other predators that hunt by sight.
The spider’s narrow, elongated body and its brown or grey colour help the disguise. When disturbed, it usually remains motionless or slowly drops from its perch on a thread of silk. Because it is active only at night, many people encounter it only by chance, when a torch beam picks out its shining eyes.
Is the net-casting spider dangerous to humans?
No, the net-casting spider is not dangerous to humans. Like almost all spiders it has venom for killing small prey, but it is shy, rarely bites and has no record of causing serious harm to people.
The spider is more likely to freeze or flee than to bite when disturbed. A bite, if it ever occurred, would probably cause only mild local pain like that of a small insect sting. The spider is best observed from a distance and should not be handled, both for its own safety and because it is easily harmed by rough handling.
Key points for safe coexistence include:
- Leave the spider where it is, since it eats small insects.
- Avoid shining a strong light directly on the spider for long periods during hunting.
- Do not tear down its framework lines, which the spider rebuilds nightly.
How does the net-casting spider reproduce?
The net-casting spider reproduces by mating after the male finds a female, after which the female lays eggs in a silk sac that she hangs among vegetation. The male is smaller than the female and has swollen palps that carry sperm, as in other spiders.
The egg sac is often a small, rounded, papery structure suspended from a leaf or twig on a silken thread, and the female may remain near it for protection. The eggs hatch into spiderlings, which disperse, grow through a series of moults and become adults within roughly a year in warm climates. The lifespan of a female is usually around a year or somewhat longer, which means that the species depends on each season’s egg sacs for its numbers.
The conservation status of most net-casting spider species in India has not been assessed in detail. Habitat loss, and heavy use of insecticides in gardens, could reduce their numbers by removing both cover and prey.
What are the natural enemies of the net-casting spider?
The natural enemies of the net-casting spider include birds, lizards, praying mantises, parasitic wasps and larger spiders, which all take advantage of a small, soft-bodied animal that stays still. Camouflage is therefore the spider’s main defence, and it works best when the spider is motionless on a plant stem that resembles its own body.
Parasitic wasps are a particular threat to the egg sacs of many spiders, as they lay their own eggs in or on them. Heavy rain can also damage the delicate framework and the net, and prolonged cold weather can slow down the activity of the spider and reduce its feeding. Because the spider is small and nocturnal, its numbers in a given place can be hard to estimate, and naturalists often rely on night walks with torches to record it.
These spiders also tell us something about how animals have adapted to darkness. Their exceptional eyes, their sensitivity to sound and their ability to throw a net with precise timing show that a spider’s behaviour can be far more flexible than the common picture of a creature that simply waits in a web.
Bottom Line
The net-casting spider is a specialist night hunter that replaces the usual web with a hand-held silk net and a pair of remarkable eyes. It is harmless to people, quietly useful in gardens and a good example of how many Indian spiders hunt in ways that few people ever see.
Frequently Asked Questions
What is a net-casting spider?
A net-casting spider is a nocturnal spider of the genus Deinopis that holds a small silk net in its front legs and throws it over passing insects. It is also called the ogre-faced spider because of its two huge eyes. It belongs to the family Deinopidae.
Why is it called the ogre-faced spider?
It is called the ogre-faced spider because of the two very large central eyes on its face, which give it a staring, ogre-like look. These eyes are extremely sensitive to light and help the spider hunt on dark nights.
Is the net-casting spider poisonous?
The net-casting spider has venom for subduing small insects, but it is not considered dangerous to humans. It is shy and rarely bites. No serious harm to people from this spider is known.
Does the net-casting spider live in India?
Yes, net-casting spiders of the genus Deinopis have been recorded in India, mostly in warm and humid areas with dense vegetation, such as the Western Ghats and north-eastern states. They are easy to overlook because they look like dry twigs by day.
What does a net-casting spider eat?
A net-casting spider eats small insects that are active at night, such as moths, beetles, crickets and mosquitoes. It catches them by casting its net over walking prey or by swinging the net back over flying prey.
Does the net-casting spider build a web?
The net-casting spider does not build a large fixed web to wait for prey. It builds a small framework of lines and a stretchy net of woolly cribellate silk, which it holds in its legs and throws. It usually eats the old net and weaves a new one every night.
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