Common garden spider

Common garden spider
Araneus diadematus

Identification

The garden spider is also known as the cross spider because of the cross of white spots which usually adorns the front of the abdomen. The background colour of the abdomen is usually light brown but may be pale beige, orange or even black. The front of the body, the cephalothorax, is brown with darker bands while the legs, which arise from the cephalothorax, are banded pale and dark brown.

When fully grown, a heavy-bodied female garden spider may reach a body length of 1.5cm. The slim-bodied males are much smaller (0.75cm) and are only noticed if looked for.

Distribution

True to its name, the spider is very common in gardens throughout the country. It is also found in a variety of other habitats and is widely distributed in Europe.

Behaviour

To catch its prey, the garden spider constructs an orb-web which is two-dimensional and resembles a dart board. Made of very fine silk and beaded with tiny drops of gluey silk, the orb is up to 30cm wide but it may span a gap of up to 3m across using extra support threads.

The spider waits in a head-down position at the centre of the web or lies hidden among nearby vegetation where it remains in contact by means of a signal thread. When an insect flies into the web the spider approaches the source of the vibrations, bites it and wraps it in silk. The spider does not feed by chewing its prey but by sucking out the juices.

When the web becomes badly damaged, or loses its stickiness because of the effects of wind and rain, the threads are rolled into a ball and eaten by the spider to recycle the nutrients. A newly built web takes about two hours to construct and it is begun by drifting a silk line across a gap on the breeze.

Life cycle

Garden spiders usually reach adulthood during July and August, when the males appear in, or near, the female's web. Courtship is a lengthy affair in which the male repeatedly tweaks the silk threads to coax the female into mating. Later, in September and October, many females become swollen with eggs and often turn reddish in colour. They may be found searching around houses for sheltered spots for their egg cocoons. During the winter most of the adult spiders die.

Young spiders hatch from their cocoon during warm spring weather (April to June). A mass of 100 to 200 tiny yellow and black spiderlings stays together for some days before dispersing. Once on their own, and without any guidance, they proceed to make perfect little webs!

Living with humans

Given that the garden spider is very common in Britain, the number of recorded cases of bites from this species is extremely small. Nevertheless, bites can occur when, for example, a specimen drops down the back of a person's neck while gardening! Resulting symptoms can include swelling of the affected area and nausea. Garden spiders should not be killed though as they help to control insect pests.