Spiders in the Garden: Why You Should Leave Them Be?

The main spider species found in British gardens

There are around 1,600 different spider species in our territory. And this diversity is certainly still underestimated! Suffice to say that cataloguing them all could take a very long time. Nevertheless, these spiders can be classified into different families which help distinguish them.

Orb-weaver Spiders

Orb-weavers, including the very common European garden spider (Arameus diadematus), are widespread in our environment. These spiders build vertical spiral webs at the centre of which they lie in wait, head down. If the web breaks, they rebuild it entirely—but not before eating the old one to absorb the amino acids it contains.

Orb-weavers are relatively large spiders (some reaching up to 5 cm!) with distinct colour patterns that vary from one species to another.

House Spiders (Tegenaria)

While the common house spider (Tegenaria domestica) lives indoors, many other species of Tegenaria prefer dark corners in the garden, such as wood piles, dead leaves, low walls, grasses, or low vegetation… There, they spin horizontal webs, recognisable by the funnel in which they hide.

Tegenaria spiders are often striking due to their long legs and dark bodies. However, they only prey on small insects.

Green Huntsman Spiders (Micrommata)

As their name suggests, these small spiders from the Sparassidae family have an emerald-green body, making them nearly invisible when lying in wait on a leaf. These spiders do not spin webs but patiently wait for prey among vegetation. They are wandering spiders.

Clockwise from top left: an orb-weaver, a house spider, and a green huntsman spider

Crab Spiders

Also known as Thomisidae, these spiders have the distinctive feature of longer front legs than back legs. This characteristic forces them to move sideways, like a crab. They do not spin webs but often perch on flowers, taking on their colour for camouflage.

Argiope Spiders

Argiopes are spiders from the Araneidae family, often coloured in black and yellow. They weave vertical, circular, and sticky webs at the centre of which they wait for prey. They particularly favour sunny and humid areas, such as meadows, groves, or fallow land.

Jumping Spiders

These small spiders from the Salticidae family do not spin webs. They stand out for their excellent eyesight when hunting. They can even memorise their surroundings. Due to their small size, they often mimic ants. Additionally, they can leap—either to catch prey or to escape danger.

Wolf Spiders

Also known as Lycosidae, these spiders move along the ground to stalk prey and do not spin webs. They are beige or brown in colour. Females carry their egg sacs with them.

Clockwise from top left: a crab spider, an argiope, a jumping spider, and a wolf spider

The case of the European black widow

All spiders found in France are harmless, except for the European black widow (Latrodectus tredecimguttatus), also known as the malmignatte or Mediterranean black widow. The latter vernacular name stems from its habitat. It is found in the South and Corsica but has also been spotted along the Atlantic coast. It lives under stones, among tree roots, or in plants.

This venomous spider is recognisable by its black body, punctate with red, sometimes orange or yellow spots. Typically, it bites when disturbed or threatened. Its venom, containing alpha-latrotoxin, causes various symptoms such as nausea, swelling, abdominal pain, headaches, and excessive sweating…

The European black widow

This venom, injected in small quantities, is not deadly except for those with allergies. Nevertheless, it is strongly advised to consult a doctor in case of a confirmed or suspected bite.

The Essential Role of Spiders in Pest Control

In a healthy garden, the presence of spiders is a valuable indicator of biodiversity. Indeed, spiders are pure carnivores that never touch the plants in the vegetable garden, ornamental garden or orchard. On the other hand, they play a central role: that of a generalist predator, constantly intervening in the regulation of insect populations. Unlike certain specialised helpers such as ladybird larvae or lacewings, spiders do not target just one type of prey. They capture whatever comes within their reach, as long as the size remains suitable for their own morphology. This lack of specialisation makes them opportunistic and effective predators of pests.

Their diet is extensive: flies and midges, mosquitoes, small beetles, whiteflies, psyllids, thrips, winged aphids and scale insects, butterflies and young caterpillars, crane flies, and even some individuals of dreaded pests such as leafhoppers, cabbage whites, box tree moths or certain cutworms. As a result, they limit pest insect outbreaks and actively contribute to the garden’s biological balance. Their presence in greenhouses, flower beds or fruit trees is therefore a significant, albeit very discreet, asset.

The impact of this predation is all the more significant because spiders are active during periods when other helpers are still scarce. From the first days of spring, certain species can be observed hunting on foliage or in the litter layer, long before hoverfly or ground beetle populations are fully established. Conversely, several species continue their activity well into autumn, extending regulation beyond the peak season.

They are also important because they have their rightful place in the food chain. Many birds, mammals, amphibians and reptiles also feed on them.

Spiders: Effective Hunters with Varied Strategies

The diversity of spiders isn’t limited to their shapes or colours. It’s particularly evident in their hunting strategies, remarkably adapted to the various mediums of the garden. This behavioural diversity allows spiders to occupy all ecological strata, from the soil to the treetops, from the vegetable patch to dry stone walls.

Orb-weaving spiders, like the European garden spider, construct circular webs suspended between stems or vertical structures. These traps are formidable for catching flying insects. The central thread of the web, sensitive to vibrations, alerts the predator waiting nearby. This method is particularly effective in late summer when populations of flies or winged aphids peak.

Other species, known as hunters, adopt a mobile approach. They don’t spin webs to trap prey but actively spot, pursue and capture them. This is the case with small jumping spiders that move visibly on walls, leaves or warm stones. Their excellent vision and agility make them predators targeting fast insects like fruit flies, winged ants or young shield bugs.

Some spiders prefer ambush tactics. This is the strategy of crab spiders, which blend into a flower or foliage, motionless, waiting for an unwary pollinator to come within reach. Despite occasional predation on solitary bees or hoverflies, their impact remains marginal and contributes to controlling harmful insects.

Finally, many species employ mixed or opportunistic techniques. House spiders, for example, weave dense sheets of web in dark or seldom-visited places. Their funnel-shaped structure traps both creeping and weak flying insects.

How to encourage spiders in the garden? Spiders are valuable allies in the garden, helping to naturally control pests. Here are some tips to make your garden more spider-friendly: - **Avoid pesticides**: Chemicals harm spiders and their prey. Opt for organic gardening methods. - **Provide shelter**: Leave areas of long grass, piles of leaves, or wood to create hiding spots. - **Plant diversity**: A variety of plants attracts insects, which in turn attract spiders. - **Reduce tidiness**: A slightly wild garden offers more habitats for spiders to thrive. - **Water sources**: Spiders need moisture, so a small pond or damp areas can help. By welcoming spiders, you’ll promote a balanced ecosystem in your garden!

The presence of spiders in the garden is therefore a tremendous asset in terms of organic pest control. The more fearful among us should be reasonable and accept their presence. And others can create favourable conditions to encourage their arrival:

• Avoiding the use of plant protection products, even those of natural origin, as they are highly harmful to spiders. Non-selective insecticides and fungicides reduce food resources by killing prey or altering their behaviour.
• Maintaining refuge areas. Spiders are sensitive to the structure of their environment. Wood piles, stone heaps, old walls, stumps, and dense hedges provide micro-habitats where they can thrive, reproduce, and overwinter. These elements should remain in place for several seasons to be truly effective. You can also adopt the principle of differential mowing
• Preserving vegetation in winter, particularly hollow stems, faded perennials, or tall grasses along borders. These structures serve as hiding places for many species, especially egg cocoons or juveniles in the growth phase. Delayed pruning, carried out in late winter, allows populations to survive undisturbed.
• Conserving webs in garden sheds, attics, garages, chicken coops, wood stores… and nests in the form of silk cocoons.
• Diversifying habitats by alternating dry and damp areas, shaded corners and sunny spots, dense vegetation and open spaces… to cater to everyone’s preferences.