Spiders form the largest order of arachnids and rank seventh in total species diversity. They are found worldwide on every continent except for Antarctica, and have become established in nearly every habitat with the exceptions of air and sea colonization. 

Unfortunately, spiders are all too frequently portrayed as creepy and are feared by a large proportion of the population. Yet they are an essential part of the natural world and carry out many activities which ultimately benefit ourselves.

Spiders eat lots of insects, and their primary ‘role’ in nearly every ecosystem they live within is controlling insect populations. Some families, like orb weavers, do this through passive hunting with their signature webs. Others, like wolf spiders, do this through active hunting. 

Because many species overwinter, they can help reduce insect numbers early in the agricultural season, giving farmers, horticulturalists and gardeners, a head start as the growing season begins. Furthermore, spiders are a crucial food source for a variety of birds, lizards, wasps, and mammals, helping to maintain global species diversity.

Self-aware 

Their abilities and capacities go far beyond controlling insect populations with recent evidence suggesting they have the mental capacity for self-awareness. Self-awareness is the capacity for introspection and the ability to recognize oneself as an individual separate from the environment and other individuals. 

The capacity for self-awareness has been extensively studied in animals such as elephants, primates and cetaceans but there is little knowledge of this capacity in animals such as spiders and other invertebrates. Fortunately, anecdotal evidence now provides us with a strong argument to suggest that animals such as spiders are just as ‘self-aware’ as we are.

Deep in the Peruvian Amazon, a spider of the Cyclosa genus builds an intricate, lifelike replica of itself constructed from leaves, dead bug parts, and other scraps. The lifelike replica is created as a spider decoy to deter would be predators. They arrange debris along specialized silk strands called stabilimenta in a symmetrical form that makes it look almost exactly like a larger spider hanging in the web. 

The presence of the decoy provides these spiders with a higher survival rate against potential predators like paper wasps because the wasps end up attacking the debris in the web rather than the spider itself.

For a spider to make the decoy spider out of twigs and leaves, it must understand itself as an individual separate from the environment and from other individuals. It must know what it looks like, and that it sits in a web, and must know how to create the structure which represents itself, anecdotally demonstrating their capacity for self-awareness.

Relationship builders

Some spiders develop close relationships with narrow-mouthed frogs. The burrowing theraphosidae tarantula in southeastern Peru is capable of eating the Dotted humming frog, yet they live together in close quarters and in apparent harmony. 

The spiders benefit from this relationship as the frogs eat the ants that would eat the spiders eggs, whilst the frogs benefit by receiving protection from predation by snakes, geckos and other spiders, and by eating the small invertebrates that are attracted to prey remains left by the spider. 

Spiders listen to their webs

Web- weaving spiders weave their webs to catch prey and attract mates. They have poor eyesight and thus appear torely on vibrations from the silk strands to locate prey and find deformities in the web. As a spider plucks and pulls on the web, sending out ripples in every direction, it can sense the vibrations in each of its eight legs.

The silk can vibrate at a wide range of frequencies, which gives the spider vital information about the state of its web and the presence of prey. Spiders determine how the silk vibrates by creating transverse waves by bouncing up and down on their web and longitudinal waves by plucking the strands of silk.

Those waves alter the silk's vibrational frequency by tweaking the composition of the silk's proteins and by adjusting the tension of the silk in the web. Together, these techniques can help a spider pinpoint any damage to its webs—and any prey that might have become ensnared.

And because spider silk can vibrate at so many frequencies, the spider can sense movements as small as a hundred nanometers—1/1000 the width of a human hair.

Forward planners

Jumping spider species have excellent vision and awareness of their environment. Portia fimbriata, a member of this spider-snacking subfamily, methodically plans winding detours to sneak up on prey spiders. Portia can even find hidden prey, suggesting that the predator can visualize its prey's location and a path to get there.

Other species have also demonstrated such abilities in behavioural tests. Individuals were placed on a tower on a platform surrounded by moats. From atop the tower, a jumping spider could see two distant boxes: one containing spider fragments, the other containing unappetizing leaves.  To reach the box containing the meal, the spider would have to crawl down the tower and onto the platform, which also had two pillars leading to separate suspended walkways—one to the food, one to the leaves.

But once the spider started its descent from the tower, the researchers emptied out the boxes, preventing it from getting visual reminders of the meal’s location. It turned out that each species tested was overwhelmingly successful at finding its way to the box containing food—despite the fact that none of the subjects could see the food mid-detour. Demonstrating an abstract sense of the food’s location and a working plan for how to navigate the walkways.

Ability to count

Spiders of the family salticidae, which hunt other spiders for food, have shown to be able to distinguish between numbers of prey in the range of 1-3. Behavioural researchers set the spiders up with two towers, with little viewing screens. 

At the first (the starting tower), the spiders saw scenes of prey that they quite commonly eat. At the second tower (the viewing tower), the spiders saw a different number of the same kind of prey. The spiders looked longer at the second tower when the prey number displayed there differed from the number at the first tower. 

It is thought that  while on the Starting Tower, the test spider loads a representation of prey number into working memory and that, while on the Viewing Tower, it compares the scene it was viewing with a representation of the scene acquired while on the Starting Tower.

Great athletes

The Australian huntsman (Family Sparassidae) can run 40 body lengths per second, about eight times faster than the fastest human runners.

Other spiders have great throwing skills. To catch moths, the bolas spider spins a thread with a sticky glob of silk on the end. The glob mimics the scent of a female moth. When a male moth comes to investigate, the spider throws the globe at the moth, catches it then reels it in.

Spiders can survive under water

The diving bell spider spends its entire life in the water, creating an underwater dome-shaped web that fills with air to help them to breathe.

Spiders are great mums

All spider mothers protect their eggs and some continue to provide protections for their spiderlings.

Trapdoor spider mothers allow spiderlings to live in the home burrow for nine months, before they dig their own burrows nearby.

Wolf spider mums strap their egg sacs to their bodies and carry them around. Just before hatching, the mother perforates the egg sac to help the immature spiders out. Once hatched, mom carries her babies on her back until they are old enough to take care of themselves, with the young entangling their legs together to keep hold. Mother wolf spiders even help their babies drink water, leaving a few legs in the water source and allowing the immature spiderlings to climb down.

Female ant-mimicking spiders secrete a nutritious milk-like substance on which its young offspring are entirely dependent. The spiderlings ingest this nutritious milk droplets until the subadult stage. This supply of milk is indispensable for offspring survival in the early stages and complements their foraging in later stages, and this maternal care continues after the offspring reach maturity and become independent. 

Spiders work as a team

Most spiders live alone, but a small number have evolved a level of sociality and community. Communal spiders work together to build, maintain, and clean their webs. They cooperate in capturing prey, and dine together when they snare a large feast.

Anelosimus eximius, constructs webs that can reach more than 25ft (7.6m) feet long and 5ft (1.5m) wide. A web that size could contain as many as 50,000 individual spiders. The colony contains adult males and females as well as youngsters, but the majority of spiders on the web are females. 

The females feed their offspring by vomiting up food, just like mother birds. They even regurgitate food for juveniles other than their own, caring for the youngest in the colony in a sort of spider day-care.

Two different Chikunia spider species in Indonesia live together in communal social groups and individuals from both species feed their own young and the young of their neighbours. The species are closely related and live in harmony together in large colonies

Spiders have personalities

The roles in spider colonies are usually sorted on the basis of age, sex and personality. Certain spiders are more likely to spend their days attacking predators, while others are more likely to repair the webs, help keep parasites away, clean the web, rear the young, and so on. 

In other words, social spiders have distinct personalities, which in turn help to define their roles in the community.

Therefore, rather than spiders being an animal that many of us fear, they are in fact an animal for us to revere. So next time you see a spider think of the capacity these animals have to understand their own world and the good they may be doing to help to control insect numbers in your garden.

Read more: 

One Life: Bats | One Life: Hedgehog Day

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