Neoscona

Physical description and identification

Neoscona is a large, cosmopolitan genus of orb-weavers in the family Araneidae, with roughly 120 described species. They are the plain, hairy, brown-and-grey orb-weavers of hedges, fences, field edges and house walls, and in much of North America a Neoscona is the spider people mean when they say a big web appeared on the porch overnight.

One correction first: the genus was erected by the French arachnologist Eugène Simon in 1864, not 1895 as many pages state. The name is usually translated as "reed spinner".

Adults

• Size: females of the common species run about 7–20 mm in body length; N. crucifera reaches the top of that range and small species such as N. adianta sit near the bottom. Males are smaller and slimmer, but the gap is modest compared with the golden orb-weavers — a mature male of a big species is still a substantial spider.
• Colour: brown, rust, tan or grey, usually mottled, with the legs banded in alternating light and dark rings. The top of the abdomen carries a paler leaf-shaped folium edged with a wavy dark line, or in N. arabesca a dark central stripe bordered in white and yellow.
• The belly mark: the single most useful clue in the genus. Turn the spider's underside to the light and most species show a dark rectangular patch bounded by a pair of pale comma-shaped or squarish white spots. Very few other orb-weavers have it.
• Separating it from Araneus: under a lens, the groove in the middle of the carapace is a long lengthwise furrow in Neoscona and a short, round pit in Araneus. That single character, plus the belly mark, settles most identifications.

Eggs and egg sacs

In late summer and autumn the female builds a flattened, silk-wrapped egg sac holding several hundred eggs — up to about a thousand in the largest species — and hides it under bark, a window ledge, a fence rail or a rolled leaf near her web. She rarely survives long after laying. The sac, not the adult, carries the population through winter.

Spiderlings

Spiderlings emerge in spring, pale and soft, and cluster briefly on a sheet of tangled silk before scattering. They disperse by ballooning, drifting on threads of silk, then build small orbs of their own and grow through repeated moults until the last one produces an adult in mid to late summer.

The web

The classic vertical orb with an open hub, anything from 20 cm to well over half a metre across, slung between shrubs, grass stems, fence wires, eaves or a window frame. In most species the spider spins it in the evening, hangs head-down at the hub through the night, then eats the silk before dawn and hides in a curled leaf or a gap in the brickwork; N. arabesca and some others stay out by day. Larger females keep a signal line from the hub to the retreat so they can feel a catch without leaving cover. See our guide to spider webs for how the spiral is built.

Where Neoscona spiders live

Neoscona is close to worldwide. Species occur throughout North and Central America, South America, Africa, Europe, Asia and Australasia, and the pantropical N. nautica has been carried by shipping to ports on most continents. India and southern Asia are especially rich in described species, and Africa holds many more.

In the United States the genus is represented above all by Neoscona crucifera, common from New England to Texas and Florida, alongside the smaller arabesque orb-weaver, the red-femured spotted orb-weaver of the southeast and the western spotted orb-weaver of the Pacific states and Mexico. In Europe, N. adianta is a spider of heath and rough grassland.

The habitat description that circulates online — "grasslands" — is far too narrow. The genus uses grassland, but it is just as at home in open woodland, forest edges, hedgerows, orchards, marsh margins, city parks and the outside walls of buildings. What the spiders actually need is a gap of open air between two solid anchor points and a supply of flying insects, which is why outdoor lights are such reliable places to find them.

Are Neoscona spiders venomous?

Yes, in the sense that applies to nearly every spider: venom is how a 12 mm spider subdues a moth that could otherwise destroy its web. It is not medically significant to humans, pets or livestock. No Neoscona species has an antivenom, none is needed, and no serious envenomation has been recorded anywhere in the genus's very large range. Araneid orb-weavers as a family include no dangerous species; these spiders are unrelated to the widows and recluses and share none of their venom chemistry.

Can Neoscona spiders bite?

They can, though it takes persistence to provoke one. A Neoscona disturbed in its web drops on a dragline, and one found in the open runs or plays dead. Bites happen when a spider is trapped against skin — inside a glove, under a shirt collar, or gripped between fingers — and they are uncommon even among people who handle spiders regularly.

A bite from a large female is often compared to a bee sting: a sharp, immediate pain with a small red mark and mild swelling, fading over a few hours to a day. Smaller individuals may not break the skin at all. Wash the site, apply a cold pack and take an ordinary painkiller if needed. See a doctor only if swelling spreads well beyond the bite or you develop hives or breathing difficulty, which indicates an allergic reaction rather than the venom.

Ecological importance and behavior of Neoscona spiders

Neoscona spiders are among the most abundant aerial insect predators in temperate and tropical landscapes, and their value lies in sheer numbers. A single hedgerow can carry dozens of webs, each intercepting flies, mosquitoes, midges, moths, small beetles, leafhoppers and crane flies night after night. They are a recognised part of the natural control of crop pests, which is why the genus turns up so often in orchard and rice-field surveys.

Rebuilding the web: taking the orb down each morning is not waste. The spider eats most of the old silk and recycles the protein into the replacement, so a fresh, fully sticky trap costs far less than it looks. It also lets the spider move a web that is not catching, and removes a structure that would advertise it to birds all day.

Natural predators: birds take spiders caught in the open, mud-dauber and spider-hunting wasps stock their nests with orb-weavers of exactly this size, and mantises and parasitoid wasps take a steady share. Hiding in a crevice through daylight is the main defence, backed up by dropping from the web at the first strong vibration.

Prey-predator dynamics: the genus overlaps closely with Eriophora, which works the same night shift at a larger size, and with the day-active Argiope garden spiders, which occupy the same shrubs but hunt at a different hour. That partitioning of time and height is why several orb-weavers can share one garden.

Seasonal behaviour: in temperate regions these are annual spiders, most visible in late summer and autumn when the females reach full size. Males mature first, abandon web-building and wander, plucking a courtship rhythm on a female's silk before crossing it. Adults die with the first hard frosts.

Relationship with humans: harmless and beneficial. A web on a doorway is a nuisance rather than a hazard, and since the spider removes it each morning, moving the outdoor light or clearing the anchor points does more than any spray.

Species in the genus and similar spiders

Quick facts

Did you know?

• Eugène Simon named an extraordinary share of the world's orb-weavers, Neoscona and Eriophora among them, in the same year — 1864 — early in a career that produced thousands of spider descriptions.
• The pale spots either side of the dark patch on the underside of the abdomen are the fastest way to name the genus in the field, and they are visible in a photograph taken from below the web.
• Neoscona nautica earned its name by travelling: it has been carried by ships to ports across the tropics and subtropics and is now one of the most widely distributed orb-weavers on earth.
• Rice-field and orchard surveys in Asia regularly list Neoscona among the dominant spider genera, making it a quietly important part of natural pest control.
• A spider that seems to "disappear" from a porch every morning has not gone anywhere. It has eaten its web and is flattened into a crack a hand's width away, waiting for dusk.

In summary, Neoscona is the everyday orb-weaver of the world's gardens and field edges: plain, abundant, entirely harmless and responsible for removing a remarkable weight of flying insects. Learn the belly mark and the lengthwise carapace groove, and the whole orb weaver family becomes easier to read.