HOMES AND GARDENS - SPIDERS (Arachnidae)




 

 

Just about any building hosts the distinctive Pholcus phalangioides or Daddy Long-legs Spider (body 8mm), whose irregular and seemingly flimsy web can be found on skirting boards, walls, picture frames, light fittings – and almost anything else, for that matter.

The average three-bedroom house with garage and shed can host a fair number of them. Crane flies (Tipula sp) are among the favoured prey – even though the web is full of air, the fly’s struggling with its long legs usually just fastens it more securely. This can even happen with other spiders, including fairly large ones. The second image above shows this, with the Pholcus phalangioides web having snared prey which was trying to run up the side of the living room door. The predator did not get wihin reach of the prey but pulled on the strands of the web with speed and dexterity to trap it, looking for all the world as if she was playing the organ. The whole process took about four minutes.

House Spiders (Tegenaria gigantea, body 14-18mm) always have their webs, which can be much smaller than expected given the size of the spider, at ground level. The species causes panic in countless households in the autumn by running fast across the carpet or appearing overnight in the bath. The females can live for a number of years and can survive without food or water for many months.

The jumping spider Salticus scenicus from the Salticidae family is common in gardens and outbuildings. About 6mm long, they can propel themselves at great alacrity for several centimetres from a standing start to catch fair-sized prey, having stalked the target carefully.

The Salticidae are the largest family of spiders, with at least 4,000 species internationally. All have exceptional binocular vision, enabling acute judgement of distance when jumping. This can include from, say, a greenhouse to a water butt, as happened with the pictured spider, but they always deposit a safety line"> first just in case.

A species not often seen in the light is Dysdera crocata (12mm), which can give a nasty nip if provoked. They prey largely on woodlice and in the wild are found under logs and stones. The pictured one was uncovered by the shifting of a dustbin near a shed. They are widespread and may be found at also any time of year.

The False Widow Spider (Steatoda nobilis, to 14mm) is an introduced species which has increased dramatically in southern England over the last 20 years or so. It varies in markings and in size. They have been in my garden for several years, including on a pot containing cucumber plants and beneath a purpose-built insect box, where the female took a large Megachile species leaf-cutter bee in 2014 (see image above).

Given the widespread and often imprecise negative publicity surrounding the species in Britain, it seems best to quote in detail the profile on the Spider Recording Scheme website: “This spider is found mainly around houses, though more rarely indoors. It constructs a scaffold web that differs from others of the genus in the exceptional strength of the silk and in the tubular retreat that is at least partly concealed in a deep crack or hole. The species has been known to bite a human but the spider has received a lot of unjustified and inaccurate media statements about its danger to humans and its spread in Britain. Bites to humans are unlikely to happen in normal circumstances since the spiders are usually confined to their web, in cracks in walls or under window sills. The bite in most people would be little different to a bee sting, and there are currently few definite recorded occurrences in Britain since 1979, many reports almost certainly being the result of non-spider-related causes which have incorrectly been assumed to be the result of 'false widows'. The males are mature in the summer and autumn, the females probably throughout the year.”

Steatoda bipunctata is smaller, 6mm or so, but the females can live up to four years. The bulbous abdomen is typical of the genus, one of which, Steatoda grossa, has been found preying on Black Widow spiders in the USA. Steatoda bipunctata has a close association with mankind, as houses and outbuildings offer a suitable habitat – the pictured spider was found in a greenhouse. They have a tangled web and can feed on ants and woodlice among other species. The pictured female, who astutely had placed her web on the front of one of the logs featured on the Wasps page in this section and used for nesting by numerous aculeates, had just caught a Crossocerus annulipes solitary wasp.

Larger (10mm) and much less common, but also in one instance found in a greenhouse, is Marpissa muscosa, a nationally notable species mentioned in the Woodland & Hedgerow section of the website where the male is pictured. As a secretive species, they might well have been in this location for years, and given the numbers of potential invertebrate prey which enter greenhouses it seems a good choice.

Amaurobius fenestralis (10mm) is one of the lace-webbed spiders and difficult to separate from Amaurobius similis. The latter seems to have an association with houses while Amaurobius fenestralis is recorded mostly in woodland. The species is common and widespread.

Xysticus cristatus (7mm) is the commonest Crab Spider in the UK and is found in low vegetation, on the ground or on walls in all sorts of places. Despite their powerful predatory abilities, they are the usual prey for the spider-hunting wasp Dipogon variegatus (8mm), which nests in almost any cavity, including in house walls with soft mortar. Dipogon variegatus is shown in more detail in the Heathland pages here.

Since gardens provide a perfect habitat for spiders, with abundant habitats in a fairly small area, Pompilidae (spider-hunting wasps) do well, though probably they are not noticed that often. Arachnospila anceps is dealt with in some detail on the Heathland pages of this website, but the pictured female dug her burrow and caught her prey in a rockery within two metres of a kitchen window.

On the same section of rockery, which has some topsoil on a basically sandy soil beneath, a female Auplopus carbonarius (also dealt with in more detail in the Heathland section) spent many minutes visiting and collecting earth to take back to her nest for constructing the cells in which the prey spiders are placed.

The most-often-seen Pompilid species in that same garden is Anoplius nigerrimus (12mm), which in 2005 took advantage of the greenhouse for catching prey. It made no difference whether the spiders were inside or out, the Anoplius (almost certainly more than one) hunted them down and interred them in various spots nearby. These included the vegetable patch, once in a fallow section where radishes had been grown and at least once in among the cabbages.

The most intriguing piece of prey capture came from the side of the greenhouse, where a number of spiders had webs along the upturned-v shaped junction of the glass and the metal framework. They were sitting targets, but the wasp faced a difficult job in getting such sizeable prey down the vertical face of the glass.

Usually Anoplius nigerrimus travel backwards with prey, but this one did the only thing she could, given the influence of gravity, and had the spider in front, as the image shows. Assisted by algae on the glass, she successfully skated down and got away with her parcel, an indication perhaps as to why Pompilidae are so successful.

One group of eight-legged invertebrates are not strictly spiders, though they hail from the wider family which also includes ticks. These are mites, of which the dashing Red Velvet Mite (Eutrombidium sp., 4mm) is the largest. While the adult possesses four pairs of legs, in the earlier stages of its life there are only three.

This mite preys on just about anything smaller such as springtails and some beetles, while others that live in the soil or leaf litter break down and recycle vegetation. As a group, mites are prolific in gardens.

Images © Jeremy Early. All rights reserved.

In 2013 I published My Side of the Fence – the Natural History of a Surrey Garden. Details may be found, and orders placed, via this hyperlink My Side of the Fence. In November 2015 Surrey Wildlife Trust published the atlas Soldierflies, their allies and Conopidae of Surrey, jointly written by David Baldock and me. Details are on this web page: Atlas.

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