Tag Archives: arachnology

A Few Notes on Autumn Spiders

Well, it’s that time of the year again when Summer begins to change into Autumn… but it’s more of a summer than June, July and even August gave us. This time of the year is when spiders become very apparent on and sometimes in our houses. Many people become alarmed by some of the spiders they see, particularly the large Tegenaria House Spiders, and Garden or Cross Spiders, and lately the larger species of False Widow, Steatoda nobilis. But there are many species on the move at this time of the year, and the main motivation is sex, males looking for females, and females sometimes trying to find good real estate to set up home in to raise their young. Think of them as eight-legged yummie-mummies.

Anyhow, here are the ones I get asked most about:

The House Spider – Tegenaria duellica (also sometimes known as T. gigantea)

A long-legged male Tegenaria duellica. The large clubbed shaped palps (some people call them antennae) and extremely long legs indicate a male.

In late summer and early autumn the males often enter houses and sheds looking for females. They will also fight bitterly with other males over females. Some of these males seem to live very long lives, mating in a succession of years. When the female accepts a male as a mate he moves into her web with her and the two can often be seen together in one web on autumn evenings. This relationship lasts until the female becomes pregnant, and shortly before she gives birth he either leaves or is turfed out (nobody is certain which) probably because he might eat the young, lacking her maternal instinct, but we don’t know for sure. Once males have found themselves females they settle down and you won’t see them wandering around anymore.

The Cross Spider, aka Garden Spider (Araneus diadematus)

These spiders rarely if ever enter houses, but will sometimes spin webs outside houses, and some webs are immense. They are orb-weaver spiders, named because of their classic spider-webs and bulbous orb-like bodies. The name “Cross Spider” comes from the jewel-like studded white cross marking on the abdomen. There are usually two main colour variations, the classic being darker, and more spectacular.

The classic and most common colouration of the Cross Spider, note the bejewelled cross pattern on the abdomen.
The brighter variation of the Cross Spider. This colouration seems to occur mostly in the larger females, such as this example, seen eating a small moth.

Cross Spiders can grow very large (their abdomens can be as wide as the tip of a man’s thumb, and as bulbous), and they look very exotic, which is what normally upsets people who find them. These large ones are only the females, the males being much smaller and very often eaten by the females either before or after mating. This is common with orb-weaver spiders. There is a closely-related and very similar, but even larger relative of this spider in Ireland called the Four-spotted Orb-weaver – Araneus quadratus, which I have only ever seen once before, and a few years before I took up photography.

The False Widow – Steatoda nobilis, is now a very common species in Ireland. There are two main species recorded here, the smaller and usually blacker one is Steatoda grossa. S. nobilis, as many people will know, is venomous to humans, and does on rare occasions enter houses and sheds, but usually prefers to hang in its strong tangled webs under the eaves of buildings.

A large female False Widow with woodlouse prey. This is the classic colour pattern of this species, but all black ones are almost as common.


Menage a trois – a female False Widow (centre) is courted by a long-legged male (right) while a disenchanted or possibly rejected male sulks in his web to the left.. Male False Widows are almost as large as females and often manage to mate with them, and live to mate again another day. However, if they do manage to mate unscathed, but overstay their welcome, there is only one result.

Spider eating dogfood!



This year there was an absolute plague of House Spiders (Tegenaria species) all across Ireland and the island of Great Britain. There are always noticeable numbers of these spiders in the late summer and early autumn, but this year there were virtually swarms of them. It is possibly a cyclical occurrence but not enough is known about these spiders to say for sure. Most of the spiders were the long-legged males, which leave their own webs to seek out females in autumn. Unlike many other species of spiders female Tegenarias do not seem to eat the males, and this is why there will often be males of various sizes, as they survive each year they can grow bigger. And these spiders are believed to live to at least seven years in the wild, and twenty or so in captivity. The successful male will usually live with the female in her web for a few months and then leave just before the young hatch out.

A large male Tegenaria duellica (aka T. gigantea)...the short club-ended palps that look like small legs between the front legs, indicate this is a male spider.

This year I saw and photographed something quite amazing: a large female Tegenaria eating dogfood out of a dog’s bowl! The bowl had been left outside for the cats and hedgehogs to finish off, but attracted instead this remarkable creature. A crop of the image is below to show the detail – the spider is definitely eating the chicken and turkey-flavoured dogfood.

Large female Tegenaria duellica eating dogfood out of a bowl.
Tegenaria gigantea eating dog food. You can tell this is a female by her more stocky body and palps that DO NOT have clubbed ends.

The plague of spiders has since abated, but it is worth remembering that despite their large size that Tegenarias are not aggressive. Although they easily have fangs large enough to puncture human skin this rarely happens…except in North America where the invasive European species Tegenaria agrestis is known to enter houses in the deep cold winters and bite people. In Europe it lives out of doors and does not like to come into houses, probably because it doesn’t like humans.

The population explosion of these spiders could be due to the heavy cold winter of last year wiping out predators such as small bird species. The largest spider of this species that I have recorded had an abdomen of on 23mm llong (less than an inch) and a leg span of 16cm. Their legs make them look huge, but there are larger spiders in Ireland, albeit outdoors.