Spiders

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Spiders, Pacific Northwest

Ground Wolf Spider, photo by Robert Logan
Ground Wolf Spider, photo by Robert Logan

Nearly half the total number of Spiders known to  Canada are found in, and quite often, only, in BC. Given their importance to all ecosystems in which they live, one must wonder why these beautiful creatures have received so little attention in the province.

They are ferocious creatures living in the world of arthropods. Theirs is a matriarchal society ruled by females, where males can sometimes be little more than just a meal. The study of these fascinating animals on the  BC coast, has, for the most part, been conducted by a few amateurs, but dedicated collectors.

Walk anywhere in British Columbia, and you’ll be less than a meter away from a spider. With more than 700 known species in the province, arachnids are everywhere, from mountain tops to intertidal zones. These creatures are always exciting to watch – from jumping spiders that dance to impress potential mates to yellow crab spiders that disguise themselves as flowers.

Trap Door spider
Trap Door Spider, Photo By Bud Logan

They have an ominous, but often undeserved reputation. Though most spiders are venomous and considered predators, of the many species found in Canada, few are actually considered a health threat. In fact, spiders are actually helpful in controlling other pests in the home or garden, since they feed on other harmful insects. Some can be pretty intimidating though, this trapdoor spider was actively trying to bite me as I photographed him and he was very quick.

The trapdoor spider is a very beautiful arachnid. Its length is usually around 2.5 cm but can grow to 5 cm. The spider in this photo is a male, most likely quite old, (maybe 15 yrs) and quite large, a good 4 to 5 cm in size.

The trapdoor spider has 8 eyes: 2 eyes in the center, and 3 eyes on each side of the pair in the middle. The color of this spider can range anywhere from light brown to black. It has 8 legs, and large sharp fangs.

The trapdoor spider spends most of its life underground and likes to inhabit warm areas. It lives in most of North America and is seen throughout Vancouver Island. This spider can also be found in South America, Africa, and Japan.

The trapdoor spider does not have a web-like most other spider species. It has a trap door with a burrow underneath it. This lair can be about 30 cm deep and 5cm wide. Its door, camouflaged with soil, opens & closes with silk acting as the hinge. The spider is nocturnal, meaning, it hunts at night. The trapdoor spider waits for a creature to walk close by the door and set off its trip strands of silk. When the spider feels the vibrations of the creature, it attacks.

Trapdoor Spider, photo by Bud Logan
Trapdoor Spider, photo by Bud Logan

In order to reproduce, the male trapdoor spider wanders about in search for a mate. This is about the only time you will see them. Once a male trapdoor spider has found his mate, both the male and female go into the female’s burrow. On completion of mating, the male spider runs away from the female to mate with others.

Several months after mating, the female lays her eggs within the burrow. After an interval of a few more months, the eggs hatch and remain in the burrow for a short period. Once the spiderlings leave their mother, they go forth to make there own homes, and fend for themselves. Trapdoor spiders can live up to 40 years. One in Australia lived to 43 years.

Spiders rarely bite humans. Although they’re often unpopular, the venom of most species is not very toxic to humans, usually resulting in no more than a slight swelling, inflammation, or itching sensation. Most spiders’ fangs are too small or weak to puncture human skin. Spiders will not usually attempt to bite unless accidentally trapped against the skin or grasped, or are actively guarding their egg sacs or young.

Giant House Spider, photo by Robert Logan
Giant House Spider, photo by Robert Logan

Sometimes you get to see a giant. The giant house spider is a close relative of both the hobo spider and the common house spider. The bite of this spider species, however, does not pose a threat to humans or animals. Like most spiders, though, they possess quite a potent venom to subdue their prey with, which can frequently result in an infection.

Females can grow to lengths of about 3 cm, with leg spans being typically around 4.5 cm, although some can grow even larger. Males usually have a smaller body, not more than 2.5 cm in length, and have highly variable leg spans of 2.5 cm up to 7.5 cm. The spider in this photo was a female, and as big as my hand!

The giant house spider has the same coloration as the domestic house spider, namely earthy tones of brown & muddy red or yellow. They also have noticeably hairy abdomens & legs.

Giant House Spider, photo by Robert Logan
Giant House Spider, photo by Robert Logan

Their webs are flat & messy with a funnel at one end, called, therefore, funnel webs. These webs are usually found in corners, on the floor, ceiling, between boxes in basements, attics, or any other area that is rarely disturbed. These spiders are known to lay motionless in their funnels until a small insect happens to get trapped in the web. The spider then scurries and kills it.

With speeds clocked at 1.73 ft per second, the giant house spider held the Guinness Book of World Records for fastest spider until 1987, when it was then displaced by the sun spider.

One of the most common misconceptions about spiders is that they are insects. Spiders are arachnids and are actually more closely related to mites, ticks, and scorpions. Spiders have 2 body parts, 8 legs, and usually 6 – 8 eyes, while insects are classified as having 3 body parts, 6 legs, and generally 2 compound eyes or up to 3 single eyes.

The average life span of a spider is usually 1 – 2 years, but some can live up to 20 years and a few can make over 40 years in age. Spiders lay eggs within a silken egg sac that is often ball-shaped, and either hidden in a web, affixed to a surface or carried by the female. Spiders may produce several egg sacs, each containing up to several hundred eggs. A spider grows by shedding its skin about 4 – 12 times before maturity. In many species, the mature male often wanders about in search of a mate, while the female has a territory.

Wolf Spider
Wolf Spider, Photo By Robert Logan

All produce silk, which is secreted as a liquid through spinnerets and hardens on contact with air. Spiders use silk for a variety of purposes, such as: making egg sacs, capturing prey, holding prey, making shelters or retreats, and transferring sperm during mating. Also, spiderlings extrude silk threads, that enable them to be transported by the wind, a process called ballooning.

They are predators that typically feed on living victims. They produce venom that is poisonous to their normal prey of insects, mites, and other small arthropods. Venom is injected through the hollow fangs to immobilize the prey and begin the digestion process. Spiders can only ingest liquids, so they either inject or regurgitate digestive fluids into the prey. They then suck in the digested liquid food.

Spiders use a variety of tactics to capture prey. Some species are web builders that use webbing to ensnare their victims. Others are hunters that actively search out their prey. Passive hunters, on the other hand, lay in wait for their victims, rather than searching. All are incredible to watch!

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