Tag Archives: identification

A few words on spiders…

A lot of people have been contacting me lately regarding spiders, mostly to do with identifications. Many have said they cannot find suitable guides for Ireland, so I draw your attention to my own little publication, Irish Spiders, which is available from Amazon on the Kindle at:

http://www.amazon.com/Irish-Spiders-ebook/dp/B00ALJ8JTE/ref=sr_1_1?ie=UTF8&qid=1367679075&sr=8-1&keywords=Irish+Spiders

If you download Amazon’s free Kindle Reader onto your phone, laptop, tablet or PC, then you can get this guide and always have it handy but some of you have been deeply concerned about the False Widows.

My photographic guide to spiders, available at: http://www.amazon.com/Irish-Spiders-ebook/dp/B00ALJ8JTE/ref=sr_1_1?ie=UTF8&qid=1367679075&sr=8-1&keywords=Irish+Spiders
My photographic guide to spiders, available at: http://www.amazon.com/Irish-Spiders-ebook/dp/B00ALJ8JTE/ref=sr_1_1?ie=UTF8&qid=1367679075&sr=8-1&keywords=Irish+Spiders

At this time of the year False Widows are on the move and, of course, we humans too are on the move, outdoors into our gardens to sow and plant, sit in deckchairs and have barbecues, so there are far more spider encounters than usual. But don’t worry, False Widows do not set out to bite people, most people feel little or no ill-affects when they do bite, and they are not particularly venomous, even when the venom does have an acute affect. Very handsome specimens of the smaller one, Steatoda grossa, have begun turning up quite a lot lately, such as the one pictured below.

A female of the smaller False Widow species found in Ireland, Steatoda grossa. these spiders are often shiny black, but this dark purple with cream marbled patterns are classic markings. Unlike Steatoda nobilis, S. grossa has arrowhead markings running up through the middle of its abdomen, as you can see in this photo.
A female of the smaller False Widow species found in Ireland, Steatoda grossa. these spiders are often shiny black, but this dark purple with cream marbled patterns are classic markings. Unlike Steatoda nobilis, S. grossa has arrowhead markings running up through the middle of its abdomen, as you can see in this photo.

For those who want to actively discourage these spiders, then your best friend is another spider, the Long-bodied Cellar Spider (Pholcus phalangioides), which is especially common on the east coast of Ireland. This long-legged spindly spider is a dedicated hunter of other spiders, no matter how large or toxic they are. I have seen them kill the very largest House Spiders, and False Widows, and only yesterday got a nice shot of one with a much larger Windowsill Spider (Amaurobius species) in its jaws.

A Long-bodied Cellar Spider feeding on another species. They also actively hunt, kill and eat False Widows.
A Long-bodied Cellar Spider feeding on another spider species. They also actively hunt, kill and eat False Widows.

 

Spiders and Cases of Mistaken Identity

The Missing-sector Orb-weaver, Zygiella x-notata, above, can sometimes be mistaken for the False Widow Steatoda nobilis, but is usually much brighter in colour, smaller in size and makes a completely different web.

Many spiders are very similar, and there is a lot of worry of some of them due to the colonisation of Ireland by False Widows in such numbers these days. The spider that is mostly mistaken for a False Widow is the very common Missing-sector Orb-weaver, Zygiella x-notata, which is found around the windows of houses in huge numbers. Zygiella doesn’t get to be as big as False Widows can, but since many False Widows encountered are not fully grown, then confusion is inevitable. What Zygiella does is spin a classic spider-web across the front of windows so that insects flying to the windows at night will crash into them and become entangled.. Most orb-weaving spiders spin their webs across fly-ways in the same way that poachers cast nets across rivers. But remember, the False Widows don’t do this because they target different prey. So the dozens of spiders camped around the outside of your window-frames will almost certainly be Zygiella and not False Widow. But they have a very similar body-shape and markings on the back can be superficially similar. Zygiella is usually much brighter and tends to have a silvery appearance.

On the other hand, the male Steatoda grossa False Widow, which has been recorded in Ireland since the late 19th century, can be mistaken for a House Spider, as it has very long legs and tends to scuttle along the ground and will enter houses simply by walking into them, and in this manner is extremely different to the more robust-looking Steatoda nobilis male. Unlike the females, they are not known to bite, but these spiders can get quite large (about as big as a mediu-sized House Spider)  and will frighten most people. The markings on the abdomen have a checker-board appearance like the classic markings of the female.

A large male Steatoda grossa (the smaller of the two large False Widow species found in Ireland). This spider prefers to scuttle rather than climb and can easily be mistaken for a House Spider when first seen.

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.