The adult female (above) is about 8 - 10 mm long and on the underside of the abdomen she usually has the characteristic red hourglass shape. The male is just 3 - 4 mm long, and his abdomen is elongated. The male does not bite humans. One mating can supply the female with enough sperm to last her a lifetime, and males are often, though not always, eaten after mating (see right which shows the male in black) - it mainly depends on whether the female is well-fed or not. The female lays around 400 eggs which hatch in 20 - 30 days. But cannibalism is rife among the spiderlings, and usually less than a dozen survive to meet the outside world. In a good year a healthy female can produce around nine broods. Females are sexually mature at around 2 - 4 months. The average life span for a female is six months, and for a male, around three months.

The spider is timid and nocturnal. During the daylight it spends its time in the silken tunnel retreat. Generally when a female is on her web she will hang upside down. The venom is neurotoxic, so it blocks the transmission of nerve impulses which leads to rigidity and cramp. It is said it is 15 times stronger than rattlesnake venom, but because of the small quantity injected it is not usually fatal to healthy humans on the rare occasions they are bitten providing the bite is treated promptly and correctly. About 0.5% of bites from the black widow to humans prove fatal. Strangely cats are very susceptible to the venom, but dogs are fairly resistant as are sheep and rabbits

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Left is a mature female Oplognatha ovata, Theridiidae, and on the right she has her eggs sac in which there are eggs or spiderlings. Below is the typical method of hiding her egg sac under a bent leaf which is held in position by silk. The female body length is 4 - 6 mm and the male is 3 - 5 mm. The colouring can vary with a cream or yellow abdomen with or without 2 red stripes or even one wide red band running down the middle, but they always have the black spots that can be seen in this specimen. They are usually found in vegetation.

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 on the 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.

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.

How to build a web.
First the spider raises its body up and squeezes out some silk. The air catches the thread and it becomes attached to an object. Then the spider pulls the thread tight and attaches it to the object it is standing on. Now it has a thread bridge between 2 objects. It walks across the bridge strengthening it with silk as it goes. From this bridge a frame, or outline of the web is made. Next the spokes running into the centre of the web are laid down. Then the spiral starting from the centre where a few threads placed close together are struck down to give the structure strength. Next a fairly wide spiral on the margin, and finally the central spiral, starting from the margin in almost as far as the hub. The outer margin spiral is no longer needed, and so is destroyed. The final spiral thread is the only thread that is sticky. The silk from Araneus diadematus is around 0.003 mm thick - that is just 10% of the thickness of silkworm silk.

Spiders in space
2 Araneus diadematus were sent into space and lived aboard Skylab II for some time. It was found that they could build webs in zero gravity after a few week's of trial and error, and that the webs were very similar to those built on Earth.

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.

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.

It emerges as it starts to get dark and spins its web to catch night-flying insects, the most common prey item being moths.

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.