What and What Not to be Afraid Of
“Oh my God, kill it! KILL IT!” Outbursts like these are common throughout much of the United States, and indeed, the world, when a spider’s cover is blown and they are forced to skitter this way and that along the wall or across the living room carpet to avoid being, as suggested above, speedily smashed.
It is unfortunate that so many of these harmless eight-legged critters have to pay such a price for our unfounded fears and instinctive squishing behaviors, especially since they work so hard to rid our homes of ever creepier (in the author’s personal opinion) pests such as silverfish, fleas, bed bugs, gnats, and flies.
I find that the basis for most fears of spiders is the fact that most people don’t know the different between those that are harmful to humans and those that are perfectly capable of coexisting with us peacefully. And so in the spirit of enlightenment, I have devised a way to help any and all who are curious enough to find a little bit more about those which do and do not pose a danger.
Biggest Threats:
The leading ladies and gentlemen on this list are of course the ever-beautiful female Latrodectus hesperus (black widow spider) and her renowned accomplice the Loxosceles reclusa (brown recluse spider). The runner-up and lesser known than these two is Tegenaria agrestis, or the hobo spider.
Black widow spider – Female black widows are perhaps the most easily identifiable spider in human history. The striking red markings on their undersides are a dead giveaway to their species, and whether it be in the shape of an hourglass or a simply a dot, it is safe to assume that any shiny black spider with a bulbous abdomen falls under this category and can be promptly avoided. The males of this species are smaller, shyer, and less venomous than their female counterparts, in fact there has been much speculation as to whether or not they are more venomous than the common garden spider at all! Also they look nothing like their women; they’re thin and usually mottled brown or gray.
Black widows, like cockroaches, can be found anywhere in the United States providing there is a stable source of heat (such as a human dwelling), ample supply of food (flies, woodlice, other spiders), and dark places (under your bed, in your shoe closet…). They are more prominent in warmer states because they are able to breed and catch food in the wild, outside.
Natural enemies of this spider do exist, and consist mainly of wasps such as the blue mud dauber and the spider wasp.
Brown recluse spider – While the black widow is easily identified by her shiny black exterior, large abdomen, and red shape on the underside, the brown recluse is less easily recognized because of his dull colors. The famed ‘violin shape’ (it starts from the head and points down toward the abdomen) which is supposed to be the telltale sign for this species is sadly not confined to brown recluses, nor do all brown recluses possess it. Certainly perhaps the only foolproof way of identifying these tricky arachnids is to count their eyes. It’s true! While most spiders have 8 eyes, the brown recluse is unique in that it has only 6. In addition, the abdomen of the recluse spider is devoid of markings, and their legs are smooth with no thick hairs.
Brown recluses have a smaller range than most people think, not straying further west than the Rocky Mountains and rarely venturing north of Nebraska. They prefer quieter, darker, and warmer places to raise their families, and so don’t travel as often with humans like the back widow tends to do.
Because the brown recluse is so excellent at hiding, there has not been done such an extensive study about them save for the effects of their bites, so there is said to be no natural enemy of this spider. However, people who have watched and collected data from the brown recluses in their own homes have noted seeing other spiders (particularly the jumping spider) attack and kill them with relative ease.
Hobo spider – The hobo spider is definitely a spider that people need to be more aware of. They are the true cause for countless numbers of reports of spider bites in which the brown recluse was wrongfully blamed, because both species look fairly similar at a glance and their bite patterns and symptoms are nearly identical. But just a second look at these critters can identify them in minute’s time. Hobo spiders, unlike the brown recluse, are more mottled in coloration and have distinctive ‘herringbone’ patterns on their abdomen. Their legs are also hairier than those of the brown recluse.
The easiest way to differentiate brown recluses from hobo spiders is to gauge the geographic location they are found in. The hobo spider was introduced from Europe to the Port of Seattle in the late 1920’s and they have since spread throughout the Northwestern United States and Western Canada, making them the leading cause of serious envenomation in the Northwest. Brown recluses do not live in the Northwest or Canada.
Fortunately for us Northwesterners, the hobo spider has a nice list of natural predators, particularly the crab spider, Pardosa wolf spider, and again our friend the jumping spider.
Harmless Helpers:
Now that the scary stuff is out of the way, here are a few ‘creepy crawlies’ that will not only creep up on all of the aforementioned threats, but will also keep the crawling population of fleas, mites and moths on the down-low. Not to mention they pose no danger to pets, children, or adults in the home. I’m talking about the endearing Salticidae family (jumping spiders), the docile Achaearanea tepidariorum (common house spider), and the gentle but giant Tegenaria duellica (giant house spider).
Jumping spider – If you ever see one of these little guys hopping around on your furniture, don’t be alarmed, these curious spiders are one of your greatest friends in the pest-ridding business. They are easy to identify because of their unique eye pattern, and inquisitive behavior. If approached, instead of scurrying away like other spiders would, the jumping spider will jump and turn to face the advancer, sometimes even looking up and studying them. Jumping spiders are regarded by many as being ‘cute’ because of their antics and large eyes.
Jumping spiders have excellent vision as their giant eyes would suggest, and can in fact see better than any other spider and debatably any other insect in the world. Using their vision they are able to perform fast, complex maneuvers around objects to get to their prey, which they will jump on and deliver venomous bites to with their tiny fangs. Because of their speed and eyesight, jumping spiders are capable of besting prey larger and more venomous than themselves, and I have personally witnessed them snatch flies right out of the air.
There are over 5,000 species of jumping spider in the world, but the most helpful seem to be those of the family Salticus and Phiddipus, such as the zebra spider or bold jumping spider.
Common house spider- Unlike the jumping spider which walks around with chagrin, the common house spider prefers to keep a quiet profile in a corner in your garage or basement. Sometimes referred to as “cobweb spiders”, they are gray to brown in color, with speckling on their abdomen that could be likened to the mottling found on wild bird eggs. Because of their similar size and shape, common house spiders are sometimes mistaken for black widows, but it is important to note the color of the spider before jumping to conclusions. Common house spiders are not black and have no red markings.
They are passive hunters, meaning that they make a web and wait for prey to come to them. They are excellent in keeping the numbers of destructive moths, flies, and mosquitoes down, and will even tackle wasps and yellow jackets (important especially if you have firewood brought into your home, which wasps will sometimes hibernate in). They will be content to live quietly by a window in your attic and pose no threat to humans.
Giant house spider – The giant house spider gets a horrible reputation and causes a lot of panic in Northwestern homes because it is easily mistaken for the hobo spider. And while there is no definite way to distinguish the two at a quick glance, giant house spiders tend to be more yellowish in color, with distinctive black stripes on the abdomen. In addition, they can reach a leg span of 4 inches in length, while the hobo spider will typically remain a modest 1 inch.
Because of their size, the giant house spider is able to take care of a larger number of prey, as well as take on much bigger insects than the jumping spider or common house spider could. Despite the similarities in appearance to the hobo spider, the giant house spider’s venom is harmless in comparison (nothing worse than a bumblebee’s sting) and they actually kill and eat hobo spiders themselves, making them an excellent addition to any crawlspace, basement, or garage. They are actually considered the best deterrent against a hobo spider invasion.
In Closing:
Hopefully now with the knowledge of both the dangers and helpers that you may find in your home, your mind will be put at relative ease. It is true that there is yet no manmade pesticide or trap more effective against a population of harmful insects than a good old-fashioned family of spiders. They definitely deserve better recognition for the work they do. Welcome to the wonderful world of knowledge, I pray you use it wisely!
Helpful Links:
Identifying Hobo Spiders (pdf)
Common North America Spiders
USA Spider Identification Chart
Hobo Spider Information
Spiders In and Around the House
Amazing Jumping Spiders!
, How to Identify Venomous House Spiders www.ozeldersin.com bitirme tezi,ödev,proje dönem ödevi