Spiders - Printable Version

Spiders - Printable Version

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Spiders - Tshokwane - 12-15-2016

Since I was a kid, Spiders have fascinated me, for a million reasons, and I'm probably one of the few people that I know of here where I live that likes them.

Everyone likes size, and power. Everyone likes to be the tiger, the lion, the bear, the wolf, the crocodile or the shark. The bigger the better, right?

How quickly Spiders are dismissed, only because they're tiny and "scary little critters", when in fact they're possibly the most perfect hunters on the planet, not limited to just one or two ways of catching their prey, but in thousands of ways, as many as species there are of Spiders.

And they're not just destroyers. They're also builders. How many other species we know of that can do both things and excel at it?...

Through this thread, that is bound to be corrected and perfected the same way a spider would create her web, I want to share with you my fascination for these creatures using the help from people who know much more than me about them, but that also love these animals.

RE: Spiders - Tshokwane - 12-15-2016

I will start by a new favourite of mine.

Information credits: An excellent page called The Silk Road and the owner, Tone Killick.

Lycosidae (Wolf Spiders)

The Lycosidae is the fourth largest spider family of the world encompassing 2403 species in 127 genera.

They range in size from small to very large (2.8-45 mm body size). Most species are hunting spiders at ground level using no web for catching prey. However spiders of a few genera such as Aulonia and Sosippus make sheet webs provided with a funnel retreat, very similar to the webs of agelenid spiders. Spiders of some lycosid genera make burrows in the ground lined with silk serving as retreats and a place for the females to guard their egg sacks, e.g. species of Alopecosa, Trochosa, and Arctosa. Spiders of the Pirata genus make silk tubes in vegetation where they spend part of their time. Many other lycosids never use a retreat but are found running about in grass, leaf litter, over sandy or stony areas, across the surface of water and many other places.

Wolf spiders are often very noticeable as many are active during daylight hours running about in sunshine hunting prey on the ground or in low vegetation. The females of some species attach the globular egg sack to the spinners, which is then carried about. After the juvenile spiders emerge from the egg sack they will climb up on to the mothers abdomen making it appear much larger. The spiderlings will stay well protected on the abdomen for several days or even weeks. Eventually they disperse and start a life on their own.

*This image is copyright of its original author

RE: Spiders - Ngala - 12-16-2016

Good way to start @"Majingilane", i'm interested a lot to the world of spiders and insects; nice information and photos.

This is a female of Pardosa sp., with the spiderlings on the back, typical of this family. Location: Lancshire, United Kingdom. Credits to Bill Senior's Invertebrate Photographs.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 01-01-2017

Credits to The Silk Road

Six legged Pisaura mirabilis, Nursery web spider.

If a spider is injured on the abdomen (opisthosoma), it usually amounts to a death sentence. Spiders have an open network which means its arteries carry haemolymph, the arthropod equivalent of mammalian blood, out into the tissue spaces where it diffuses past individual cells before being collected back into the heart. There are few, if any, veins in this system and definitely no capillaries. So if there is an injury which causes an opening in the side of the body, this fluid leaks out and the animal dies. Losing a leg or two is a different ball game altogether. At the joints of the legs the spider has sphincters which close off therefore saving the spider from bleeding to death.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to ‎Josh Phangurha‎.

A female Hogna carolinensis, the largest North American Lycosid, that I photographed in Arizona. I spotted it due to its intense eye shine that was illuminated by my torch. When I knelt down to take some shots, an unfortunate moth landed right in front of those huge sensitive eyes. The image shows what happened next...

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to The Silk Road.

Heteropoda davidbowie - Photographed by Nik Nimbus

The spider known as Heteropoda davidbowie was named in 2008 by Dr. Peter Jäger, a German arachnologist at the Senckenberg Research Institute in Frankfurt. While the David Bowie spider is found in parts of Malaysia, Singapore, Indonesia and Thailand, Jäger discovered the species when Germans who owned the spider as a pet sent him photos requesting to identify it for them. One of the spider's most striking features is its bright orange face, said to resemble Bowie's painted appearance during the early days of his career.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to The Silk Road.

Siler semiglaucus feasting on ant eggs - Photographed by Husni Che Ngah in Malaysia

Siler semiglaucus is a colourful inhabitant of the rainforests of south to southeast Asia, from Sri Lanka to the Philippines.

It was originally described under the genus Cyllobelus, but was later transferred to the genus Siler by Prószyński (1985). The colouration of males and females is similar, but males bear a feathery bottle brush of black setae on their first legs.. S.semiglaucus is known to selectively associate with, and to prey upon, ants. It often attacks these ants from the rear, biting and then retreating before a subsequent approach.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to Nicky Bay.

Nephila sp. with cicada prey.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to Sean McCann.

Male Habronattus americanus.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to Jurgen Otto.

Male Maratus personatus.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to The Silk Road.

Maratus volans (peacock spider) feeding on a long legged fly. Central Coast, NSW. Australia - Photographed by Michael Doe

In Australia, the Jumping spider family, Salticidae, has been partially revised with 380+ species in 80+ genera though it has been estimated that there could be as much as 1000 species in 95 genera.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to The Silk Road and Mary Holland.

Spider silk is manufactured within glands inside the spider’s abdomen. Amazingly, a wide variety of silk is made, each type having its own particular use. Strong, elastic silk is used to build the foundation of a web. Sticky threads are produced to trap prey. Soft, fluffy silk cushions the eggs while a tough, papery silk envelopes the exterior of the egg sac. Each kind of silk is extruded in liquid form through tiny “nozzles” collectively located in organs called “spinnerets.” These are conical or finger-like appendages visible at the back side of the spider’s abdomen. Most spiders have at least two pairs of spinnerets, with each spinneret containing many, many silk-producing “spigots.” As the spider brushes the liquid silk from the spinnerets, the silk proteins are oriented in a fashion that renders them a solid fiber. Many spiders have special “combs” on their legs that help them spin out the silk strands.

Argiope aurantia

*This image is copyright of its original author

Spider Spinnerets

All spiders are capable of spinning silk, regardless of whether they use it to spin webs and trap prey or not. Egg sacs, drag lines (so they can find their way home), drop lines (to catch them if they fall) egg cases and transportation (young spiders disperse by “ballooning” as the wind catches their silk and carries them off) are some of the other functions silk plays in the life of a spider. Silk is extruded through nozzles called spinnerets located near the tip of the abdomen. Typically a spider has two or three pairs of spinnerets. Each one is the exterior tip of an interior silk gland and has a valve which can control the thickness and the speed with which the silk is extruded. The different glands produce different kinds of silk used for different purposes. The spinnerets work independently for some functions, and together for others. In the photograph, the black and yellow argiope is turning her grasshopper prey around and around as she produces a sheet of silk in which she wraps it. Most, if not all, of the spinnerets are in use.

*This image is copyright of its original author

All spiders spin silk — some use it to build webs, eggs sacs, draglines, wrap prey and/or disperse in the air. Inside their bodies are glands which produce different types of silk material for different purposes. Liquified silk proteins are pushed out spinnerets, or silk-spinning organs, located at the tip of a spider’s abdomen (most spiders have six). Once the silk solution comes in contact with the air, it solidifies. Each spinneret has a spigot, or nozzle, which controls the consistency of the silk by forming smaller or larger strands. By winding different silk varieties together in varying proportions, spiders can form a wide range of fiber material. Spider silk is extremely strong and flexible. Some varieties are five times as strong as an equal mass of steel and twice as strong as an equal mass of Kevlar.

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to Mary Holland - Naturally Curious.

Barn Spiders Spinning

If there is a fairly large spider spinning orb webs in a corner of your shed or barn and it has striped gray, brown and white legs, chances are great that it is a Barn Spider, Araneus cavaticus. These spiders are nocturnal, so it’s often the early-rising/late-to-bed folks that observe these arachnids. During the day, Barn Spiders hide in a nearby crevice where birds and other predators cannot easily find them. Webs are freshly constructed every night (or every few nights) and the remains of the old web are eaten in order to conserve the valuable silk. During the night Barn Spiders can be found hanging in the center of their web, awaiting prey.

Male Barn Spiders reach between ¼” and ½” in size and adult females typically are around ¾”. Most males spin webs less frequently and spend much of their lives wandering, attempting to find a female to mate with. Thus, most Barns Spiders you see in webs tend to be females.

The spider in E. B. White’s Charlotte’s Web was based on a Barn Spider. In his inimitable way, White named her Charlotte A. Cavatica, a reference to the Barn Spider’s scientific name. One of Charlotte’s daughters, after asking what her mother’s middle initial was, names herself Aranea.

Araneus cavaticus

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to Mary Holland - Naturally Curious.

Spinnerets, located at the far end of a spider’s abdomen, serve as spigots through which silk is exuded, but they also have another function for some species of arachnids. Female wolf spiders use their spinnerets to grasp their eggs sacs, enabling them to carry and guard their eggs until they hatch. In order not to damage the eggs when she moves, the spider tilts her abdomen up slightly. Catching prey with this added encumbrance and in this position must take great skill. Once the wolf spider’s eggs hatch, the young climb up on top of the abdomen where they spend their first days before dispersing. (Nursery web spiders also carry their egg sacs with them, but clasp them with their jaws, or chelicerae, and small, leg-like appendages called pedipalps.).

*This image is copyright of its original author

RE: Spiders - Tshokwane - 02-01-2017

Credits to Mary Holland - Naturally Curious.

Spiderlings Dispersing

Although many spider eggs hatch in the spring, there are some that hatch in the fall. Most spiderlings stay within the egg sac until they undergo their first molt – their small cast skins can be seen inside the old egg sac. After molting they emerge and cluster together, still living largely upon the remnants of yolk sac in their abdomens. In several days the spiderlings are ready to disperse, which is necessary to avoid competition for food and prevent cannibalism among the hungry siblings.

Some species, especially ground dwellers, disperse by walking, often over relatively short distances. Others, particularly foliage dwellers and many web builders, mainly disperse by ballooning. To balloon, spiderlings crawl to the top of a blade of grass, a twig or a branch, point their abdomens up in the air and release a strand of silk. Air currents catch the silk, often called gossamer, and lift the spider up and carry it off. Aerial dispersal may take a spiderling just a few feet away or much, much farther – spiderlings have been found as far as 990 miles from land. (Charles Darwin noted spiderlings landing on the rigging of the Beagle, 62 miles out to sea).