Araneus alboventris
Araneus alboventris is one of the small, easily overlooked orb weavers of the eastern United States — a yellowish-green spider barely wider than a grain of rice, marked with a single black patch outlined in crimson and, as its name says, an unbroken white belly. Most sightings happen in a narrow window around July, when the adults mature and their little orbs appear in roadside shrubs.
By Dr Richard J. Pearce (PhD)Published May 24, 2022Updated September 13, 2026✓ Reviewed by Dr. James Watuwa
In this guide
Physical description and identification
Araneus alboventris is one of the miniature members of Araneus, a genus otherwise known for the chunky garden spiders that fill an autumn hedge. It is small enough to be missed entirely unless you are looking at the web, and the pattern that identifies it — a single dark blotch ringed in red on a yellow-green abdomen — is only a few millimetres wide. Turn the spider over, or look up at it from below, and the second field mark appears: a clean white underside that gives the species its name.
Adults
- Size: mature females average about 7 mm (0.28 in) in body length. Males are noticeably smaller and slimmer, with longer legs relative to the body and swollen tips to the pedipalps — the normal arrangement throughout the genus.
- Colour: the ground colour is yellowish green to pale lime. The abdomen carries a well-defined black patch on the upper surface, outlined by a thin crimson border, and the underside is white. The carapace is paler green and the legs are green, finely haired and often faintly ringed.
- Eyes: eight small eyes in two rows of four, all much the same size. The side pairs are set close together on low mounds at the outer corners of the head region, the standard orb weaver arrangement.
- Other features: the legs and body carry fine hairs known as setae, which register air movement and the struggle of prey in the web. As with all small Araneus, a photograph will place a spider in the group but not reliably to species; the adult genitalia under a microscope are the only certain characters.
Eggs and egg sac
The female encloses her eggs in a silk sac, which protects them from parasitic wasps, desiccation and weather. The sac is fixed under a leaf, in a curl of dead foliage or against a stem near the web rather than on the orb itself, where it would be conspicuous and constantly disturbed. Each female may produce more than one sac in a season if she survives long enough.
Spiderlings
One claim repeated about this species needs correcting: the hatchlings do not look like small adults. Newly emerged spiderlings are pale, soft and essentially unmarked, and the green ground colour, the black patch and its red border appear gradually across several moults. The young disperse early — most while still a millimetre or two long — by climbing to an exposed twig and releasing silk into the breeze. From there they build progressively larger orbs through the summer. Our guide to the spider life cycle follows the same sequence in more detail.
The web
The web is a true orb: a vertical wheel of radii and a sticky spiral around an open hub, scaled down to 10–20 cm across. It is built in the outer twigs of shrubs and low woody growth, usually between knee and head height rather than in the canopy, and is rebuilt or repaired frequently because sticky silk loses its grip once it is dusty. The spider normally sits head-down at the hub through the night and retreats by day to a curl of leaf at the web's edge, holding a signal thread that transmits every impact. For how the radii, hub and spiral are assembled in sequence, see our guide to spider webs.
Where Araneus alboventris lives
The species is North American and, on the available records, an eastern one: it is reported through the eastern and east-central United States, with the densest concentration of sightings in the mid-Atlantic and the Southeast — Maryland, Virginia and the states around them. Listing the distribution as simply “the United States” overstates it; there is no evidence of the species in the arid west or on the Pacific coast.
Habitat is shrubbery in the broad sense: the brushy margins of woodland, hedgerows, old fields growing back to scrub, stream banks and garden borders with dense twiggy growth. What the spider needs is a fork of fine branches to anchor a small orb, insect traffic passing through it, and a curled leaf for a retreat. It is a spider of edges rather than deep forest or open grassland, and it does not come into houses.
Is Araneus alboventris venomous?
Yes, in the way that nearly every spider is venomous: it injects a small dose of insect-specific venom into prey caught in the orb. For people that is where the story ends. No North American orb weaver is medically significant, no antivenom exists for any of them because none is needed, and this species has no recorded history of harmful bites. It is unrelated to the recluse and widow spiders and shares none of the chemistry that makes those groups dangerous.
Can Araneus alboventris bite?
It can, in the sense that it has functioning fangs, but bites on people are essentially unrecorded and the spider is not remotely inclined to try. An orb weaver's defence is to drop out of the web on a dragline, vibrate the orb into a blur, or flatten itself against a twig. Biting is a last resort that requires the spider to be squeezed — trapped in a glove, or caught between a hand and a branch.
If it happened, the result would be a pinprick with a small red mark that fades within hours. Wash the site with soap and water and use a cold pack if it is tender. Pain that grows, spreading redness or difficulty breathing are not effects of orb weaver venom and would suggest an allergic reaction or an infected wound, which is a reason to see a doctor.
Check the underside: several small green orb weavers share a wooded edge, but the plain white venter of A. alboventris — the feature behind the name alboventris, “white belly” — is visible from below while the spider sits in its web, and does not need the animal in the hand.
Ecological importance and behavior of Araneus alboventris
Everything this spider does is organised around the web. It builds, waits, and interprets vibration; it does not roam in search of prey. An insect strikes the sticky spiral, the spider reads the direction and size of the impact from the hub, runs out along a radius, bites and wraps the catch in broad bands of silk. Prey is what flies at shrub height: small flies, midges, mosquitoes, leafhoppers, aphids, parasitic wasps and small moths.
Natural predators: the serious threat is not birds but wasps. Mud daubers and spider wasps specialise in hunting orb weavers at the web, paralysing them and sealing them into mud or burrow cells as food for a single larva. Birds take adults and egg sacs, jumping spiders raid the orbs, and parasitoid wasps lay eggs on living spiders. Being small and green in green foliage is this species' main defence.
Prey-predator dynamics: a small orb catches small insects, and that separates the species from the larger orb weavers sharing the same hedge. Where an adult garden spider filters bees and large flies out of the air, A. alboventris removes the fraction of the insect community that passes straight through a coarse web. The two are neighbours rather than competitors.
Seasonal behaviour: the reason this spider is “a July spider” is developmental, not behavioural. Juveniles are present and feeding from spring, but they are tiny and their webs go unnoticed; adults mature together in midsummer, become large enough to photograph, and the males then leave their webs to search for females. Egg sacs are produced in late summer, and the adults die before winter.
Relationship with humans: the spider is harmless and useful. It never enters buildings, its web is small enough to walk past without noticing, and a hedge full of them is a working insect filter that costs nothing.
Similar spiders and how to tell them apart
| Spider | How it differs from Araneus alboventris |
|---|---|
| Araneus cingulatus | Also small and green, but the abdomen carries a rust-orange blotch and a scatter of separate crimson spots instead of one black patch with a red outline. Smaller on average, and a spider of high conifer foliage rather than low shrubs. |
| Araneus niveus | Green with a brown abdominal patch and two conspicuous white spots. No red border, no white venter, and males have a hook-shaped process on the palp. |
| Arabesque orb weaver (Neoscona arabesca) | Larger and never green: tan to reddish brown with dark comma-shaped dashes down the abdomen. Common on the same shrub edges but in a bigger, more conspicuous web. |
| Furrow orb weaver (Larinioides cornutus) | Grey to brown with an oak-leaf-shaped furrow pattern, larger and heavier, and strongly associated with water and man-made structures rather than dry scrub. |
| Green lynx spider | Bright green and far bigger, with long spiny legs and no web at all. It ambushes pollinators on flower heads instead of trapping them. |
Quick facts
| Scientific name | Araneus alboventris (Emerton, 1884), family Araneidae. |
|---|---|
| Distribution | Eastern and east-central United States, most often recorded in the mid-Atlantic and Southeast. |
| Habitat | Shrubbery and low woody growth on woodland edges, hedgerows, old fields, stream banks and garden borders. |
| Web type | Small vertical orb, roughly 10–20 cm across, with an open hub and a leaf retreat at the edge. |
| Diet | Small flies, midges, mosquitoes, leafhoppers, aphids, small wasps and moths. |
| Lifespan | About one year; adults mature in midsummer and die before winter. |
| Predators | Mud dauber and spider wasps, parasitoid wasps, birds and jumping spiders. |
| IUCN status | Not evaluated. Too small and too little surveyed for any trend to be known. |
Did you know?
- The name is a description, not a dedication: alboventris combines the Latin albus, white, with venter, belly — the white underside you see when the spider is hanging above you in its web.
- It was described in 1884 by James Henry Emerton, an American arachnologist and scientific illustrator whose meticulous drawings of New England spiders are still consulted by specialists more than a century later.
- Most small Araneus species have no accepted common name. That is why this page, and the scientific literature, use the binomial rather than a nickname.
- Sticky spiral silk works by glue droplets, and those droplets absorb water from the air. In dry conditions the web loses adhesion, which is one reason orb weavers rebuild so often.
- Green colour in small orb weavers comes from pigments in the body wall, and those pigments break down in alcohol. Museum specimens of green spiders usually look cream or yellow.
In summary, Araneus alboventris is a harmless midsummer miniature of the eastern hedgerow: yellow-green above with one crimson-ringed black patch, white below, sitting in a small orb that quietly removes gnats and leafhoppers from the air around it.
Frequently asked questions about the araneus alboventris
What does an Araneus alboventris spider look like?
It is a small yellowish-green orb weaver with one well-defined black patch on the upper abdomen, outlined by a thin crimson border, and a plain white underside. The carapace and legs are green and finely haired. Mature females are about 7 mm long; males are smaller and slimmer with longer legs.
How big does Araneus alboventris get?
Mature females average around 7 mm, or roughly 0.28 inches, in body length. Males are distinctly smaller and lighter-bodied, as they are throughout the genus Araneus. Even a full-grown female is small enough that the web is usually noticed before the spider sitting at its hub.
Is Araneus alboventris dangerous to humans?
No. It is venomous only in the sense that it uses venom on insects, and that venom has no medical significance for people or pets. There is no antivenom for any North American orb weaver because none is needed. The spider is timid and bites on humans are essentially unrecorded.
What kind of web does Araneus alboventris build?
A classic vertical orb: radial spokes, an open hub and a sticky capture spiral, about 10 to 20 centimetres across. It is anchored in the outer twigs of shrubs, usually between knee and head height, and the spider keeps a retreat in a curled leaf at the edge of the web.
Why is Araneus alboventris seen mostly in July?
Because that is when the adults mature. Juveniles are present and feeding from spring, but they are tiny and their webs go unnoticed. In midsummer the spiders reach full size, the males leave their webs to search for mates, and both sexes become visible and photographable for a few weeks.
Where is Araneus alboventris found?
In the eastern and east-central United States, with most records from the mid-Atlantic states and the Southeast. It favours shrubby edges: hedgerows, woodland margins, old fields returning to scrub, stream banks and garden borders. There is no evidence of the species in the arid west or on the Pacific coast.
Do Araneus alboventris spiderlings look like the adults?
No, despite frequent claims to the contrary. Newly hatched spiderlings are pale, soft and almost unmarked. The green ground colour, the black dorsal patch and its red border develop gradually over several moults, so a half-grown juvenile can look like a different species entirely.
How does Araneus alboventris protect its eggs?
The female wraps the eggs in a silk sac and fixes it under a leaf, inside a curl of dead foliage or against a stem close to the web rather than on the orb itself. The silk shields the eggs from drying out, from weather and from some parasitic wasps until the spiderlings emerge.
What eats Araneus alboventris?
Mud dauber wasps and spider wasps are the main specialist predators, hunting orb weavers at their webs and storing them, paralysed, as food for a single larva. Birds take adults and egg sacs, jumping spiders raid the orbs, and parasitoid wasps lay their eggs directly on living spiders.
What is the ecological role of Araneus alboventris?
Its small orb catches the small insects that pass straight through the coarser webs of larger orb weavers, so it fills a distinct slot in the shrub layer. A hedgerow with many of these webs removes large numbers of gnats, midges, leafhoppers and aphids, and the spiders themselves feed wasps and birds.
References
- World Spider Catalog (2026). Araneus alboventris (Emerton, 1884). Natural History Museum Bern. wsc.nmbe.ch/spec-data/9278/taxon
