Spiders
There are more than 35,000 species of spiders worldwide but less than a 1,000 of these are found in the UK. Although they are seen as beneficial to our environment, many people do have an inherent fear of spiders, known as Arachnophobia. This causes feelings of uneasiness at the mere sight of spiders, leading to excessive sweating, crying and panic attacks.
The majority of species of spiders found in the UK are not considered dangerous and they rarely bite. If you do get a spider bite, it often has little effect on most people, while a few species can cause an exceptional reaction due to their venom.
The majority of the spiders in this country produce webs and this is a key way to identify if spiders are present in your home or business.
In general, spiders can be found in dark, secluded areas, both in your home and garden.
Look for spider webs Tthe size and shape of spider webs vary by species. Some are orb-shaped while others are funnel-shaped.
Some spider species live in burrows rather than webs, while others are free ranging and take refuge in crevices.
Some species of spiders are attracted to moist environments so check your basements, walls, sheds and other damp locations.
Other species can be found in places such as attics, the junction of a wall and ceiling, cupboards and storage boxes.
Spiders feed on other insects and prey on ants, flies, woodlice and other spiders, so where there is a plentiful supply of other insects, spiders will wait to find their next meal.
As the temperature drops in Autumn, spiders become more active, looking for a mate they come out of their hiding places. Towards the end of Autumn many die off, but some hibernate until the following Spring.
Spider eggs are laid into a silken sac, on average about 100 eggs in each sac, which may be fixed to a surface, hidden in the web or carried by the female. Signs of the sacs fixed indoors indicate that soon there will be more spiders around.
Spiders rarely bite in the UK and none of the indigenous UK spiders are considered dangerous. Most spider bites will have little effect on people but some species can cause a reaction due to the venom injected.
Facts about the bites of a False Widow, Yellow Sack and a Brown Recluse spider.
Adult False Widow spiders are not naturally aggressive towards people. They only bite as a defensive measure if they feel threatened. Most defensive bites to people occur when the spider is unintentionally squeezed or pinched. Bites may result in localised pain, tingling and small swelling around the bite.
Occasionally more serious symptoms can occur but these are an exceptional reaction of the individual to the spider's venom.
Appearance
Brown bulbous abdomen with pale markings - females grow to 15mm.
Habits
Hangs upside down from 'tangle webs' in dark corners.
Closely resembles the black widow spider.
The web is typically a random scaffolding of threads.
Natural habits include low vegetation and undisturbed areas.
In urban environments they occur in unused sheds, outbuildings and indoors.
Bites are fairly rare and only occur when the spider is feeling threatened. Generally this will produce localised short-term pain and swelling.
Their bite is sharp and painful and will cause erythema (red marking of the skin like a rash) and swelling. A wheal may develop, producing a necrotic area, which can take eight weeks to heal. Pain or numbness at the site of the bite, may be followed by sweating and nausea lasting for up to 24 hours.
Adult Yellow Sac spiders can be seen from April through November. They emerge at night to look for food. They drop to the floor to seek cover when disturbed.
They are likely to enter homes during early Autumn when their outdoor food supply decreases.
Appearance
Pale in colour, abdomen can be yellow or beige with a faint dark stripe running lengthwise.
6mm to 9.5 mm long.
4 pairs of legs, the 1st pair longer than the 4th.
Eight similarly sized dark eyes arranged in two horizontal rows.
Life Cycle
A female produces around 5 egg sacs each with 30 to 48 eggs. The female may produce several egg masses during her lifetime.
Eggs are laid in autumn.
Young spiders emerge the following spring.
Approximately 30% of the adult males get eaten by females after mating.
Habits
Feeding is usually on small insects.
Location - They build a silken tube or sac (instead of a web) in a protected area, which is used as their daytime retreat.
Externally this can be within a leaf or under logs; Indoors this can be or at the junction of a wall and ceiling or behind pictures and shelves. They are normally outdoor spiders, but will set-up indoors if there are small insects available and are found on walls and in corners close to the ceiling, they drop from ceilings on silk threads.
They only bite when crushed, handled or disturbed. Both sexes are venomous. Reactions to bites will vary - some people are unaffected, some may feel a pinprick whilst others may feel a stinging sensation followed by intense pain.
Some people may not be aware of the bite for 2 to 8 hours.
Brown Recluse spiders are often called 'fiddleback' or 'violin' spiders because of the violin-shaped marking on the top surface which points from the head area toward the abdomen.
Appearance
6 mm to 19mm long.
Brown or deep yellow colour.
Long, thin, brown legs covered with fine hairs.
Six eyes that are arranged in pairs in a semicircle.
Life Cycle
Eggs are laid primarily from May to July.
The female lays about 50 eggs in an off-white silky sac approx. 2/3 inch diameter.
Young spiders emerge around 1 month later.
It takes on average one year to reach the adult stage.
Adults can live 1-2 years.
Habits
Locations - They prefer secluded, dark, undisturbed sites indoors or outdoors. Indoors, they may be found in attics, basements, cuilt in cupboards, and ductwork, in storage boxes, shoes or behind furniture. Externally they may be found in barns, storage sheds, garages and under logs, loose stones and stacks of lumber.
Feeding - They prefer dead insects.
They can survive about 6 months without food or water.
Visibility - The sac serves as the spider's daytime retreat. They tend to look for food at night.
Other Common Spider Species
There are thousands of species of spiders around the world, but here in the UK only a few are considered as common pests:
Wolf spiders hunt at night but spend the day hidden amongst moss and decaying matter.
Appearance
Adult female approximately 8 mm in length, males approximately 6 mm in length. They are generally brown to grey in colour.
Life Cycle
Wolf spider mothers carry their egg sacs around with them attached to spinnerets under the abdomen.
When the young spiders hatch, they climb onto their mother's back where they live for the first few weeks of life.
Habits
They live in a shallow burrow, with an open and unadorned entrance.
Harvestman spiders can be found in fields and forests.
Appearance
Adults are from 3.5 to 9mm in length. The upper body surface has light grey/brown pattern whilst the lower surface is typically cream.
Life Cycle
The females lay eggs in moist soil.
The eggs survive through winter and hatch in the spring.
Only one batch of eggs is laid each year.
Habits
They climb tree trunks or look for food on the ground.
They feed on many soft bodied arthropods, including aphids, caterpillars, beetle larvae, and small slugs.
Common House spiders can be found in your home or business.
Appearance
Adult body length excluding legs is 6 to 10mm. It has a yellow/brown body with faint markings. The abdomen is pale-grey-brown with short hairs.
Life Cycle
The egg sac produced by the female is spherical, covered with a layer of silk and placed within the web structure.
The male will mate several times with the female before dying.
Adults may live for several years.
Habits
Found in buildings, sheds and walls.
This spider produces a sheet web.
The cellar spider is sometimes known as the daddy longlegs spider. It gets its name due to being primarily found on ceilings of rooms or cellars.
Appearance
Adults are 2.5cm, four long pairs of legs and two body parts.
Very long, thin legs.
Will rapidly shake its body on the web when disturbed.
Habits
Diet primarily consists of insects which they catch and eat.
Breed at any time of the year not being affected by seasons.
Spiders are most likely to enter your home in the autumn in search of a warm place to spend the winter.
The best advice, in general, is to leave them alone. This can be difficult for the many people who have a real fear of spiders.
The majority of spider infestations are more of an annoyance - particularly their webs. However, on occasions, more serious situations can occur. One example of this is the False Widow spider (the common name for a group of species in the genus Steatoda), where there is potential for harm from their bites.
To control a small infestation, you could use DIY spider products however an established infestation may require professional treatment to ensure that it does not reoccur.
The most effective way to control spiders is to limit their food source. This includes clearing away dead flies, beetles and other crawling insects.
Vacuum regularly, both high and low and in particular sheltered spots such as the backs of cupboards, underneath work surfaces or under/behind large furniture.
Remove webs on a regular basis.
Fill in gaps - in walls, around pipework and under doors.
Remove sheltering sites such as firewood piles, garden bags, compost heaps and general clutter around the garden and near your property.
Deter all insects by using lighting in a way that deters other insects including flies and moths that spiders feed on.