Wasp spiders (Argiope bruennichi) catch insects in large orb webs, including grasshoppers, crickets, flies, and other insects. They are predators in garden vegetation, but available studies do not show that they reduce garden pest damage or establish their overall effect on pollinators and other beneficial insects.
What is a wasp spider?
“Wasp spider” refers here to Argiope bruennichi, a spider rather than a wasp. The Natural History Museum lists that as the accepted species name and “Wasp Spider” as its English common name (Natural History Museum species dictionary).
In the UK, the female is conspicuous, with yellow, black, and white stripes; the smaller male is pale brown. Females build large orb webs in vegetation, often in open long grass. The Wildlife Trusts lists gardens among the species’ habitats and gives April to October as the UK viewing window. The British Arachnological Society says adults mature in August and September, females die in autumn, and young emerge from egg sacs in spring. These seasonal details are UK-specific and should not be assumed for other climates (The Wildlife Trusts; British Arachnological Society).
What do wasp spiders eat?
The most accurate short answer is insects caught in the web. The British Arachnological Society names crickets and grasshoppers as favorite prey for large females, along with flies and other insects. Their diet is broad rather than limited to a particular garden pest.
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A 2005 study examined 163 webs in two Polish habitats and recorded 430 prey items. These included beetles, flies, aphids and other true bugs, hymenopterans, moths and butterflies, scorpionflies, dragonflies, grasshoppers and crickets, and lacewings. The mix differed between habitats, so the list is not a fixed menu for every garden (2005 study of prey in two Polish habitats).
A University of Basel repository abstract for a 2009 field study in uncut grassland near Zurich reports that Hymenoptera and Orthoptera together made up about 90% of prey biomass in that study. It estimated that adult females captured about 90 mg of fresh-weight prey per web per day. Those figures describe a three-day study in a particular Swiss grassland, not a typical garden capture rate or a measure of pest control (University of Basel repository record).
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The Polish study also recorded a semi-digested common frog as an unusual item. That observation is exceptional; it is not evidence that wasp spiders regularly hunt vertebrates.
Are wasp spiders beneficial in the garden?
They can reasonably be considered part of a garden’s natural insect-predator community: they catch insects in vegetation, including some species gardeners may regard as pests. But their prey is varied, and it may include insects with other ecological value. The cited studies do not measure whether wasp spiders reduce aphid populations, protect crops, lower pesticide use, or affect pollinators in home gardens. Calling them useful predators is justified; promising that they will protect vegetables or control pests is not.
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Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallA 2008 field experiment in southern England tested prey capture, not garden outcomes. Naturally coloured spiders caught over twice as many prey as blacked-out or leaf-shielded spiders, and nearly three times as many Orthoptera. The authors interpreted the result as strong support for a prey-luring role of the spiders’ bright coloration in that experiment. It does not establish a benefit to crops or gardeners (Bush, Yu, and Herberstein, 2008).
What does the web’s zigzag silk mean?
The female’s orb web may contain a vertical or zigzag band of silk called a stabilimentum. Its function is not settled: The Wildlife Trusts says it is unclear. In the 2008 experiment, the presence or length of decorations did not explain variation in prey capture, and the paper notes conflicting results across the wider literature. The evidence does not justify saying the stripe definitely attracts prey or prevents birds from hitting the web.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What should you do if you find one?
If the web is away from a frequently used path, leaving it undisturbed allows the spider to remain part of the garden’s wildlife. If it is in the way, take ordinary care around the web and any egg sac. The cited sources do not give an authoritative relocation method, so avoid handling the spider or egg sac on the basis of unsupported advice.
UK sources describe wasp spiders as not dangerous and highly unlikely to hurt people. As with spiders generally, a bite may occur in self-defence, so there is no reason to handle one unnecessarily (British Arachnological Society; The Wildlife Trusts).
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