My Science School

Spiders are fascinating creatures. Master builders who expertly weave strands of silk into intricate webs, spiders use these both as their home and their hunting grounds. Human beings have been enthralled by the spider's ways and there have been many who have wished to enter the spiders world to learn more about web construction and arachnid behaviour.

Notes from the web

In April 2021, a group of researchers from Massachusetts Institute of Technology (MIT) along with collaborators at Studio Tomas Saraceno reported a way of translating the structure of spider's web into music. As spiders live in an environment of vibrating strings with different frequencies, which they use to sense the world around them, researchers decided to extract these rhythms of non-human origin and convert them to music.

In order to achieve their objective, a laser was used to capture the spider web. The 2D cross-sections thus obtained were then reconstructed into a 3D web network using the aid of computer algorithms. Next, different frequencies of sound were assigned to each strand of a web, thereby creating notes. These were combined based on the web's patterns to create melodies. By creating a harp-like instrument, the researchers then played the spider web music in a number of live performances around the world.

3D printing

Apart from the wow factor that such a research provides and the fact that it could act as musical inspiration as well, researchers have identified a number of other uses that might come in handy. After gaining insights into how spiders build their webs, the step-by-step knowledge could be used in constructing 3D printers that mimic these spiders and hence might be able to build complex electronic circuits.

Communication with spiders

Additionally, these experiments showed that an algorithm was able to correctly classify spider sounds into different activities, even though they sounded similar to human ears. This means that the time when human beings learn how to communicate with spiders in their own language may not be that far away!

 

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There are about 40,000 species of spiders and nearly all of them have poison glands. Fortunately, in most cases the venom is very weak and has little or no effect on man. The bite of the tarantula was once thought to cause a disease called tarantism when the victim wept and danced wildly. Now it is known that the bite is not dangerous to man.

A few spiders, however, can injure people. One of these is the black widow which lives in North America. Its bite can cause intense pain, severe illness and even death, though this is rare.

In actual fact the mouth of a spider is made in such a way that it cannot really bite. These animals use their venom as a chemical to paralyze their victim. Scientists have found that the venom of spiders in some species breaks down the tissues of the victim and turns them into a sort of jelly which the spider then sucks up because it has no means of chewing its food.

If a spider is not hungry it does not kill its victim immediately. Instead, it imprisons it by wrapping a thick web of threads round it, waiting for the right moment to inject its venom.

 

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Victorian funnel-web, trap-door spiders and mouse spiders do Victorians mistake for a Sydney funnel-web. The Melbourne trap-door spider, stanwellia grisea, looks similar to the Sydney funnel-web. It is found throughout the Melbourne metropolitan area. The Melbourne trap-door spider is quite aggressive, but rarely bites. If you are unlucky enough to be bitten, it can be painful but not dangerous. Mouse spiders, missulena bradleyi, are found on the outskirts of Melbourne, on the Mornington Peninsula and in the drier western areas of Victoria. They can also be aggressive but rarely bite. The bite is not known to be dangerous. Victorian funnel-web, mouse and trap-door spiders all live in burrows in the ground.

Funnel-webs burrow in sheltered sites under logs and rocks where they can find a cool and humid climate. Funnel-webs rush out of their burrow when potential prey, such as beetles, cockroaches, small lizards or snails, walk across silken trip-lines that the spider has placed around the outside of its burrow. They then return to their burrow to eat their meal.

 

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No, this is not true. Some female spiders do not eat their mates, however some species will eat the male, if they are smaller or food is scarce.

"We were surprised to find that such a simple characteristic such as how small males are relative to females has such a large effect on the frequency of sexual cannibalism," Wilder said.

Perhaps the most well-known example of spider-women eating spider-men is the black widow. But even that cannibalism case is overstated. For most of the many species of black widows, cannibalism is the exception, not the rule, according to Rod Crawford of the Burke Museum of Natural History & Culture at the University of Washington.

 

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It turns out that the notion is false on both counts. But a little clarification is needed.

According to entomologists at the University of California, Riverside, the term "daddy longlegs" is commonly used to refer to two distinct types of creatures: opilionids arachnids with pill-shape bodies and eight long legs that are actually not spiders, and pholcids, which have long legs and small bodies, and thus resemble opilionids, but which are true spiders.

Pholcids, or daddy long-legs spiders, are venomous predators, and although they never naturally bite people, their fangs are similar in structure to those of brown recluse spiders, and therefore can theoretically penetrate skin. For these reasons, "This is most probably the animal to which people refer when they tell the tale," the entomologists assert.

But is pholcids' venom extremely poisonous? Surprisingly, because they almost never bite, scientists have never bothered to conduct research to determine their venom's toxicity to humans . In 2004, the Discovery Channel show "Mythbusters" stepped in to fill this knowledge void. The team set out to coax a daddy longlegs spider into biting the arm of the show's co-host, Adam Savage.

 

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Sydney funnelweb spiders are not found in Victoria.

The two Victorian funnelweb spider species are relatives of the Sydney funnelweb spider. 

Funnelweb spiders are found around the east coast and the highlands of Australia (from Queensland to Tasmania) and small regions of South Australia. Most are found on the ground where they build burrows in moist, cool, sheltered areas, but some are tree-dwelling. They are regarded to be the most notorious of the Australian spiders due to their highly toxic and fast-acting venom. However, out of at least 40 species, only the male Sydney funnelweb spiders have been responsible for recorded deaths

Funnelweb spiders have a shiny black head and legs, and black to brown abdomen covered in fine hairs. The females are slightly larger (35 mm) than the males (30 mm).

The female produces a pillow-shaped silk egg sac, which she defends vigorously if disturbed. The spiderlings hatch about 3 weeks later, and stay with the mother for a few months. Funnelwebs reach maturity in about 2–4 years. The females live for 10 or more years, whereas the males die 6–9 months after maturity.

 

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The barking spider, sometimes called the whistling spider, is an Australian farantula. When disturbed, they produced a sound by rubbing their palps over their fangs. The largest are found in Queensland, and some have been found in north-west Victoria.

Barking Spiders produce their barking sound by rubbing rows of spines on their palaps against spines on their lower jaw. This noise is used to deter predators.

The deserts are prone to flash flooding and Barking Spiders live in burrows with leaky rooves. The hairs on their body trap air bubbles during flash floods and the air pocket prevents them from drowning.

Barking Spiders have brush feet with claw tufts and a film of oil produced from a special gland which gives them a suction cup ability to climb smooth vertical surfaces.

 

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On top of its head, the sea spider has a knobby projection bearing two, three, or four simple eyes. The head ends in a snout with a sucking mouth. Sea spiders feed by sucking the body juices of such marine animals as sea anemones, sponges, and sea squirts. They prefers a liquid diet which they eat standing up. They insert their long proboscis into their prey, sucking up the nutrients.

Most sea spiders eat other animals and attack invertebrates (in-VER-teh-brehts), or animals without backbones that are attached to the ocean bottom, such as corals, clams, and marine worms. A few species feed on red algae (AL-jee), a special group of plantlike ocean life that lacks true roots, stems, or leaves. Other sea spiders feed on bits of plant and animal tissues that build up under colonies of invertebrates. 

 

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Sea spiders can be identified by their long legs and tiny body. The sea spider has a small, narrow body. It usually has four pairs of long, thin legs attached to the abdomen. Attached to the head there are usually three other pairs of Appendages – a pair called chelicerae, used for grasping food; a pair of sensory projections called palps; and a pair of egg-carrying legs (sometimes underdeveloped or absent in the female). The female lays round masses of eggs on the egg-carrying legs of the male, which carries the eggs until they hatch.

Sea spiders usually come in amazingly beautiful colours. The yellow-kneed sea spider, for example, has bright yellow stripes contrasting a red body. Other sea spiders have purple stripes, bright yellow solid bodies, or black and white stripes, and so on.

 

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Pycnogonida (sea spiders) can be found all over the globe, from shallow tropical seas, to freezing oceans, to the deepest parts of the ocean over four miles below the surface. In fact, there are around 1,300 varieties of these creatures. Species found in coastal waters are usually small and have a leg span of about 1 inch (2.5 cm), those living at great depths, up to 24 inches (60 cm). The largest of them all the giant sea spider is found only in the icy water of the Antarctic. Sea spiders walk about on the ocean bottom on their slender legs or crawl among plants and animals; some may tread water.

Sea spiders either walk along the bottom with their stilt-like legs or swim just above it using an umbrella pulsing motion.[6] Sea spiders are mostly carnivorous predators or scavengers that feed on cnidarians, sponges, polychaetes, and bryozoans. Although they can feed by inserting their proboscis into sea anemones, which are much larger, most sea anemones survive this ordeal, making the sea spider a parasite rather than a predator of anemones.

 

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Sea spiders are related to insects, like ants or bees, as well as the arachnid group for which they are named, which contains spiders and centipedes. However, their name is a misnomer. Sea spiders are not actually spiders. They are marine arthropods of the class Pycnogonida. All living things are organized into groups, with successive groups sharing more characteristics in common. In one of the largest categories, kingdom, sea spiders are classified in Animalia. Many people are surprised to find out what scientists consider an animal! Although we usually think of dogs and cats as animals, any multicellular organism that is mobile and eats to get food is considered an animal in the scientific world. Animals are divided into smaller groups based on shared characteristics. Sea spiders are a member of the phylum Arthropoda. This means they are related to insects, like ants or bees, as well as the arachnid group for which they are named, which contains spiders and centipedes. However, their name is a misnomer. Sea spiders are not actually spiders. They fall in a different subgroup of Arthropoda, called Pycnogonida.

 

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