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.

2 thoughts on “A Few Notes on Autumn Spiders”

  1. I found what I think is an araneus diadematus. I am after checking the website to identfy what I found.in co Galway

  2. Sorry for the slow reply, John. I would say it highly likely that’s what you found as they are very common in autumn, and reach their full size.

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