Spiders in the Araneidae family, orb-web spiders

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Araneidae family The Araneidae family has 4 000 species world wide. Araneidae have 8 eyes. They spiders in this family spin orb webs. A typical orb web can be seen below right. Mating - when a male approaches the web of a female he is hoping to mate with he plucks the threads of her web to attract her attention, and to let her know he is not her next meal. Araneus diadematus, also known as the garden spider, the cross spider and the diadem spider. The spider on the left is Araneus diadematus, also known as the garden spider, the cross spider and the diadem spider. Usually very easy to recognise because of the large white cross on the abdomen. The top of the cross cannot be seen here as she is so big with eggs. It is one of the most common orb web spiders. This one was found in a rose bush growing up a wall, and had been there for some months. She will lay her yellow egg sac containing 400 - 800 eggs in a sheltered spot, probably attached to the wall, and stay with the eggs till she dies in the autumn. The young will emerge as it starts to warm up the following spring. At first the spiderlings will huddle together in what looks like a fuzzy ball which if touched seems to explode with spiders running in every direction. Then after their first moult they will go their separate ways. You can just see the silk issuing from her spinnerets at the end of her abdomen.

Araneus quadratus

On the right is Araneus quadratus, probably the heaviest British spider - one weighed 1.174 g, and another weighed 0.33 g but the eggs she had just laid weighed 0.76 g! The female is 9 - 15 mm long, and the male 6 - 8 mm long. The colour of both sexes varies from pale yellow to red/brown. The abdomen in the female increases hugely in size when she is heavy with eggs. It is found in tall grass, heather and bushes. Adults are sexually mature in summer and autumn. The are common in Britain and northern Europe.

Another member of this family is Nephalia sp. from New Guinea. Their huge webs are so strong that humans use them to catch fish.

Nuctenea umbratica

On the left and right is another spider in the Araneidae family, Nuctenea umbratica. It has a flattened abdomen and is rather dull coloured. During the day it is found under bark and in dark crevices, all this makes it rather hard to spot. One of its favourite hiding places is in folded up garden furniture.

It emerges as it starts to get dark and spins its web to catch night-flying insects, the most common prey item being moths. It can take moths 7 or 8 times its size. It is able to do this as it has a fast-acting poison that quickly paralyses the prey.

Also in the Araneidae family are the bolas spiders. These spiders hang from a silk thread holding its bolas (a sticky ball of silk on a thread0 by one leg. It swings the bolas so that it sticks to a passing moth. Then it reels the line, bolas and moth in. There are bolas spiders in America, Africa and Australia. In tropical America it was found that the prey items of the local bolas spider were all male "armyworm" moths. When the bolas spider was studied further it was discovered that it produced a chemical which imitated the female armyworm's sex pheromone. The the poor male moth thought it was flying towards a female eager to mate.