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GENERAL INFORMATION ABOUT SPIDERS:



THE HOBO SPIDER

Female Hobo spiderMale Hobo spider

Female (L) and Male (R) Hobo Spider

The Hobo Spider, is one of the five species of this genus found in North America., only one of which is native to the US. In Portland, Oregon the Hobo occurs quite often. The Hobo Spider has also been called the aggressive house spider and was introduced into the port of Seattle in the late 1920’s. By the mid 1960’s, it had become established in Washington, Oregon, Idaho, and British Columbia. Current distribution places it also in Montana, northern Utah, western Wyoming, and two isolated populations in Colorado.

Hobo spider mapHobo spider funnel web

The Hobo Distribution Map (L) and the Hobo's Funnel Web (R)


LIFE HISTORY:

This spider builds funnel webs, which are flat and have a funnel at one end in which the spider hides, waiting for prey. The funnel portion is commonly built into a crack or hole in a wall corner. The Hobo spider has a two year life cycle beginning with overwintering eggs that hatch in the spring.. The spiderlings find a suitable location for building a web and then spend their first year growing and molting. After overwintering a second time, the males mature ealy the following summer (June to September) and the females mature a short time after. Males wander in search of females from late June through October and may crawl into clothing and bedding. For this reason, the males are responsible for most bites. After mating most males die, before October, and females die during winter following deposition of her egg sacs.

RECOGNITION OF HOBO

Specimens range in size from 3/8 to 5/8 inch (10 to 15mm) in body length and 5/8 to 1-3/4 inches (15 to 45 mm) in leg span. The abdomen usually has a herringbone stripe pattern of brown, gray, and tan. The legs and back are conspicuously hairy. Unlike the domestic house spider, which has distinct dark rings on it’s legs, the Hobo has solid-colored legs. Two parallel grey marks run the length of the carapace. The spinnerets are long and finger-like and can be seen from above as they protrude from the tip of the abdomen. This spider is difficult to discern from closely related species, usually requiring experience and a good magnifier.

EXAMPLES OF THE HOBO SPIDER BITE:



THE BROWN RECLUSE:

The Brown Reclus spider is also well known as the "violin" spider and/or the "fiddle-back" spider due to the violin shaped marking on the carapace of some species. They are known from two principal world areas: temperate South Africa northward through the tropics into the Mediterranean region and southern Europe, and temperate and tropical zones of North and South America. In the US, the Brown Recluse is considered to be the most widespread and most important species of this group. The spider has a propensity to inhabit household goods, furnishings, etc., enabling it to be imported from overseas quite easily. This also enables it to bite before you realize it's there. As you can see from the map below, the natural range of the Brown Recluse is from southern Texas north to Nebraska, and east to eastern Tennessee and Alabama. It appears to be most concentrated in the south-central portion of the Midwest. Although reports of the Brown Recluse spiders outside it's natural range from Maine to California have occurred, these are more likely due to transport of commerce or domestic household goods.

The normal scale of the Brown Recluse (L) and the close up of their bite (R)

Numerous misidentification of the Brown Recluse spider and it’s bite is often common due to the fact that often times one needs a magnifier to see the proper markings. The wound identification is difficult without an actual specimen and with that in mind it is more normal than not to be misdiagnosed and not given the proper care right away.

The Recluse is nocturnal and searches for food such as silverfish, cockroaches, crickets, or other soft bodied species. Males will wander farther than the females and are the sex that most commonly crawl into shoes, trousers, or other clothing; or under sheets and covers on beds. Bites often occur when a spider hiding in clothing or bedding is actually trapped against skin.

After mating, which may occur from February to October within it’s normal range, 40 to 50 eggs are deposited in off-white, round, 1/4-inch (6mm) diameter silken cases. The summer months of May through August are optimal times for egg production. From one to five egg sacs will be produced during the females lifetime, which normally averages from one to two years; however four to five years is not that uncommon. The presents of shed skins and subsequent attachment in and around residences may be indicative of infestations and enable accurate identification. Additionally, the Brown Recluse’s numbers increase when living within human dwellings. When one Brown Recluse is found, numerous spiders usually can be located by visual inspection or the use of monitoring traps.

Please understand that not all Brown Recluse have the “fiddle” markings, they may be faded or absent. The species color varies from yellowish to light tan to dark brown and is covered with fine hairs.


THE BLACK WIDOW:

This picture is of both the female (black with red hour-glass marking) and male (brown and black with orange or red "dots" and white stripes) Black Widow. The fmale is busy tending to her egg sac.

No other group of spiders causes so much apprehension than do the Black Widow spiders and their close relatives. They are present in every state in the US, Southern Canada, the Caribbean, Mexico, Central, and South America, Mediterranean countries, southern Russia, New Zealand, Australia, and warmer parts of the world. They are frequently found in railroad box cars, ship holds, and interstate freight vans. In northern states, outbreaks or “blooms” occur periodically. Apparently, alternating warm spells and cold snaps in the winter and spring are detrimental to survival. In much of California, the Southwest, and the Southeast, widows are highly common, even in desert cities where irrigation is present. The brown widow was recently discovered in California.

The widow’s eggs are laid in silken sacs up to 1/2 inch (13mm) in diameter, and a female may produce four to nine egg sacs during one summer. About 300 to 400 eggs per sac is common, although there can be upwards of 800 which is very unusual. The female guards the egg sacs and moves them as necessary to repair her web. After laying eggs, the females are hungry and more likely to bite if the web is disturbed. The eggs generally hatch in 8-10 days, however the period between the egg deposition and spiderling emergence may be 2-4 weeks.

Contrary to popular belief, males are seldom devoured by the female after mating. Actually males live much longer when with a mate because he acts as a “parasite” feeding on prey captured by the female.

THE WOLF SPIDER:

The female Wolf Spider (L), a female Wolf Spider carrying her egg (C) and a female Wolf Spider carrying her hatched babies on her back (R).


Wolf spiders are large, "hairy" running spiders that are often confused with tarantulas. These spiders are active hunters and construct no web. Some of the larger species are up to 1.5 inches (38mm) in body length and can have a leg span up to 3-4 inches (7.50-10cm). The Wolf spider is commonly found in cellars in the eastern US. The Wolf spider has great eyesight and their sense of touch is also acute. For the most part, these spiders are "loners" and stay outdoors. They will find their way inside during Autumn if the weather gets cold enough.

Wold spiders are not aggressive but will inject venom freely if provoked. Though usually considered harmless to humans, the bite of some species may be painful, and even swell a bit, but rarely require medical attention. The great thing about these spiders if that they feed on bugs that often are species harmful to humans.

YELLOW SAC SPIDER:

Yellow sac spiders derive their name from their yellow color and the flattened silk tube or sac they construct and hide within during the day. During the summer months, these silken retreats can be sun on leaves of vegetation, usually near the ground. Indoors, the retreats may be found behind pictures, baseboards, ceiling tiles, and are commonly found in corners at the wall-ceiling juncture.

After mating, the female deposits her lightly woven egg sac within her silken retreat where it is somewhat protected. After emerging from their egg sac, the spiderlings remain in the silken tube for a short period then begin to venture out for food. Often, they will return to the retreat to spend the daylight hours. This spider is believed to overwinter as a juvenile, molting into adult the next spring.

There are 191 species of the “sac” spider, and the picture above (the yellow sac spider) is probably responsible for most cases of indoor spider bites throughout the country. Thankfully their bite feels like nothing more than a mosquito bite. At the most you will suffer a bit of swelling and itching.