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SPIDERS ARE OUR FRIENDS

GARDEN TIPS – Written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Published August 28, 2016

I have to admit that when I relocated to Washington a long time ago, I was deathly afraid of spiders. Since then I have come to appreciate these much misunderstood beneficial arachnids.

Spiders are not insects. They have two body segments, eight legs, and eight eyes. They also have a pair of chelicerae, appendages resembling fangs but serving as jaws. In addition they have a pair of pedipalps, appendages resembling small legs that are used for sensing objects, for helping construct a web, and for holding onto prey. Unlike most insects, spiders do not have antennae or wings, but they are capable of producing silk their entire life.

What makes spiders beneficial is that they prey on insects, providing us with natural pest control. What makes them scary is their appearance and the fact that almost every type of spider is venomous. However, that does not mean they are harmful to us. Generally, most spiders do not possess venom that causes humans any injury. If their venom does cause a problem, it usually just an itchy bite. Out of the approximately 50,000 species of spiders that exist in the world, only about 25 of them are capable of causing human illness and none are considered deadly.

The reason spiders possess venom is to aid them in gaining control over their prey who no doubt try to escape when captured. Spiders are not intent on attacking us and “taking us down” as prey. The most venomous spider in the US is the black widow and it only bites humans when disturbed or threatened.

Spiders take different approaches in capturing their prey which are usually insects. Some build sticky webs and wait for an unsuspecting insect, such as a fly, to become stuck in the strands. As the insect struggles, the spider injects it with venom to immobilize or kill it. Other spiders build webs with dry silk and quickly attack their prey when the vibrating strands alert them of their dinner’s presence. About half of all spider species do not spin webs for capturing prey. Some spiders hunt down their victims, while others sit in hiding to wait for dinner to pass in front of them.

As fall approaches, many homeowners fearful of spiders migrating indoors from outside, will spray their yard and home foundation with pesticide to kill the spiders. This is shameful. Spiders are our friends, eating all sorts of other insects and providing natural pest control just like preying mantids, lady beetles, and other beneficial insects.

This spraying is also misguided because most of the spiders found living inside a home are house spiders, not outdoor spiders. House spiders are ones adapted to indoor conditions that are not favorable to outdoor spiders. House spiders arrive in homes as egg sacs with building materials used to construct the home or on household goods. They spend their lives hidden somewhere within or under the home. When you see them in the early fall roaming about the house, they are in search of females for the purposes of mating.

Outdoor spiders are not well adapted to the limited food and water supply available inside a house. They will stay outdoors, not migrate inside to find a cozy place for winter. They are adapted to surviving winter outdoors. If they get lost and come indoors, they will die.
If you do have a number of house spiders start appearing in your house in the fall, they have come from somewhere within the house. While creepy, it should not cause you sleepless nights. Just buy a bunch of sticky spider traps at the hardware or grocery store and place them along baseboards in the corner of rooms or under the beds. If cobwebs are a problem on the outside of your house or on shrubs, simply brush them off with a broom or use a forceful spray of water to wash them off. Remember, spiders are our friends.

Spiders are much misunderstood creatures. To learn more about spiders go to the University of Washington Burke Museum website that debunks many myths you may have heard about spiders at: http://www.burkemuseum.org/blog/curated/spider-myths

SPIDERS SHOULDN’T CAUSE PANIC

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Last week I heard from a friend about one of her coworkers that ran from her office screaming. She was in such a panic that it took several minutes to determine that a spider was the cause of her distress. A bit extreme, but I can empathize with this person.

I also used to be very afraid of spiders, but over time I’ve learned to appreciate these eight-legged beasts. I can’t say I want to keep them as pets, but you won’t find me screaming if one shows up in my office.

Late summer and early fall is when area residents seem to find the most spiders inside their homes. This is erroneously attributed to the cooling weather and the need for spiders to find a warm spot for the winter. Rod Crawford, Curator of Arachnids at the University of Washington’s Burke Museum, points out that this is a myth.

Many spiders found inside of the home are ‘house spiders’ that spend their lives indoors and are adapted to the dry environment, moderate temperatures, and limited food supply found in homes. House spider species aren’t adapted to outdoor conditions and would probably not survive if you kindly scoop them up and deposit them outside. Outdoor spiders that find themselves inside a home aren’t likely to survive long either.

Crawford points out that only 8 of the 170 species of spiders found in Seattle are commonly found both outdoors and in houses. Yet, some outdoor spiders do find their way indoors at this time of year. One of these is the hobo spider (Tegenaria agrestis) that wanders about in late summer and early fall looking for a female mate. Since female hobos are seldom found indoors, the males have definitely gone astray. You have to feel a little sorry for these star-crossed guys. They can’t find their love and they won’t survive indoors.

Talk about bad luck… for years the hobo spider (initially called the aggressive house spider) has been blamed for being aggressive and poisonous. Hobos were misnamed ‘aggressive’ because of their species name ‘agrestis’ which in Latin means ‘rural.’ Hobos aren’t aggressive.

Also, hobos may not be poisonous. Arachnid specialists like Rod Crawford are casting doubt on past assumptions that the hobo spider bites are poisonous and cause necrotic wounds. Crawford points out that over the past 25 years, not one patient has come forward who (1) was initially healthy, (2) developed the “typical hobo spider bite symptoms,” and (3) was able to produce any spider that had bitten him/her.’

Crawford also notes that, ‘within the range of the brown recluse, genuine necrotic‑bite patients recover the spider about 20% of the time, so “hobo spider victims” should have managed it at least once. On the other hand, several humans and dogs developed no significant symptoms when bitten by hobo spiders that were recovered and identified. Some such cases can be explained as “dry bites,” but it seems increasingly likely that these “hobo spider bite” cases, or most of them, are not actually being caused by a spider.’

Finally, Crawford points out that it has been illogical and unfair to blame all the necrotic lesions that occur in this region on the hobo spider. There are many possible causes of a necrotic skin lesion and anyone who discovers one should consult medical experts. For more information, consult an article on spider bites and necrotic wounds by spider expert, Dr. Rick Vetter at http://spiders.ucr.edu/necrotic.html. Finally, if you find a male hobo spider indoors, don’t panic.

Published: 9/21/2012 1:04 PM

SPIDERS AND BATS ARE OUR GARDEN FRIENDS

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

This is the time of year gardeners start to prepare their gardens for winter. It’s also the time of year that Halloween decorations start to appear. Ghouls, monsters, pumpkins, spiders, and bats seem to be a pervasive theme. Halloween is all about spooky and scary things, but we do an injustice to spiders and bats who are actually two of our garden friends. Making them out to be frightening creatures is unjust.

Generally, spiders should be regarded as good guys. Why? According to Dr. Linda S. Rayor, Assistant Professor of Entomology, Cornell University, ‘Spiders are considered to be the most important terrestrial predators, eating tons of pest insects or other small arthropods every year. Spiders are generalist predators that are willing to eat almost any insect they can catch. They are abundant and found in most habitats. They only need to be left alone!’

That’s why I get upset when I hear about folks who want to spray around their homes to kill all the spiders and other insects because one or two might find their way inside. This certainly knocks the balance of nature out of kilter. When spiders migrate inside at this time of year looking for a mate or a warm spot to spend the winter, just smash them with a shoe or tissue. If you have lots of spiders migrating indoors, it probably means that you need to tighten up your home, replacing weather stripping on doors and sealing cracks and crevices that provide entry to spiders and other creatures.

A common ‘scary’ spider noticed at this time of year are the orb weavers (Araneidae). There are a variety of different orb weavers, some with interesting angled peaks or tubercles on their large abdomens. They can also be quite colorful, coming in a variety of colors including orange, yellow, black, white, and brown.

A female orb weaver can appear quite large at this time of year because she is carrying several hundred eggs in her abdomen. Before the end of fall she will create an egg sac and then die before winter arrives.

The orb weavers build amazing large wheel-like circular webs that are works of art. When insects find their way into an orb weaver’s web, their vibrations enable the spider (orbs have poor vision) to locate and trap their hapless victims. Most orb weavers rebuild their webs every day.

So if you see spiders or their webs around your yard and garden don’t be alarmed. Don’t try to kill them. They’re helping keep insect populations in check. If you see spiders inside the house, just usher them back outside where they can do some good or smash them.

Bats also eat a tremendous amount of insects, including mosquitos, and should be considered our friends. As with spiders, by encouraging bats we’re allowing nature to keep the insects in our yards and gardens in check.
Published: 9/29/2011 12:10 PM

INTERVIEW WITH A HOBO SPIDER

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Things have slowed down a bit so in the spirit of the upcoming haunting holiday, I thought I’d take the opportunity to interview a hobo spider. I must admit that meeting with this rather large and hairy arachnid was a bit disconcerting, but garden journalists like me are willing to forge ahead in the face of danger…

Mr. Hobo Spider, you used to be known as the Aggressive House Spider, but then you changed your name. How come?

Actually I was misnamed the “Agressive House Spider” because uninformed people translated my scientific name, Tegenaria agrestis, to mean “aggressive.” A correct translation of my Latin name means “mat weaver of the fields.” I was given the name of “Hobo Spider” by Rebecca J. Vest who worked with her husband Darwin Vest, the researcher who performed the original research on me and my reportedly poisonous bite. Despite this earlier defamation of my character, I am not an aggressive spider!

Why Hobo Spider?

You’d have to ask Rebecca Vest, but I suspect it’s because my family is reported to have migrated here from western Europe through the Port of Seattle sometime before the Great Depression, most likely hitchhiking as egg cases on cargo from the rural areas of Europe. In Europe, my family tends to only be found outdoors in the fields, not indoors or close to homes. I’m now found in Washington, Oregon, Idaho, Utah, Wyoming, Montana, and Colorado. I’m often encountered around the foundations of homes and beneath objects in the garden and landscape. I’m also found inside Tri-City homes in late summer.

Why come inside if you aren’t aggressive?

Late summer to early fall is mating time for hobo spiders. As a male, I search far and wide for a female mate and that includes coming indoors.

You have a rather large family. Do you all look alike?

You’re right, my family, Agelenidae, known as the funnel-web weaver family is large. There are over 500 species of funnel-web weavers around the world with 300 species in North America. We make a web that resembles a funnel.

Do you all look alike?

Some of us are quite similar in appearance, especially my closer cousins in the Tegenaria genus. I’m embarrassed to admit that experts have to compare our genitalia to tell us apart. If you want to know more you can go to this link to determine the difference between me and other look-a-like spiders: PLS 116 at http://www.puyallup.wsu.edu/plantclinic/resources/pls-res.html

You are reported to cause a bite that resembles that of a brown recluse. Is this true?

For years now, we hobo spiders have been blamed for biting humans and causing a necrotic wound with our venom. Our bites are supposedly similar to those caused by the bite of the brown recluse spider. However, the brown recluse doesn’t reside anywhere the Pacific Northwest. A recent research study of the venom of both U.S, and European Tegenaria agrestis showed that neither of our venoms causes skin lesions in rabbits, contrary to a much earlier study of our U.S. venom. A review of medical literature reveals that there is only one verified hobo spider bite case that caused a necrotic skin lesion in a patient. There is doubt that my bite was the cause in this case because the patient also had a pre-existing medical condition that could have caused the lesion. So at this point, it’s unclear if my bite causes necrotic skin lesions in humans or not.

If not, what or who do researchers think might be responsible for such skin lesions?

It could be one of the insects that commonly bite humans for their blood. This includes ticks, fleas, bed bugs, and others. There are also medical conditions that can cause similar necrotic wounds, such as a Staphylococcus bacterial skin infection or Lyme disease. I don’t like to be blamed for something that’s not my fault.

I wouldn’t either. Thank you for your time.

You’re welcome.

Published: 10/17/2009 11:06 AM

SPIDERS – OUR FRIENDS OR FOES?

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Do you view spiders as your friend or foe? Many people fear all spiders because of the few that are poisonous. Plus, few people like creatures that crawl … and most spiders can’t even come close to being thought of as cute and cuddly. It’s not very surprising that most of us regard these eight-legged creatures as our enemy, but the majority of spiders should be considered our friends.

There are only a few species of spiders encountered in our region that are considered poisonous and potentially dangerous. They’re the hobo spider, the black widow spider and the sac spider. Many other species commonly found in local yards, gardens, fields, and homes are harmless. Spiders are generally passive and only bite if trapped or threatened. Many spiders aren’t even capable of biting humans because their fangs are too short or too weak to actually puncture our skin. As our friends, they feed on insects in the garden and in the home.

I used to fear spiders … big time. Telling me they were beneficial didn’t do much to allay my fears. It wasn’t until I was given several jumping spiders (in a jar) that I was able to appreciate spiders. I still can’t say I really “like” spiders, but I do value their insect eating activities in the yard and garden.

If any spider comes close to “cute and cuddly”, it might be the jumping spider… my favorite spider. Jumping spiders, from the family Salticidae, are hunting spiders that search out and stalk their prey during the daylight hours. When ready, they suddenly jump and pounce upon their victim, usually some unsuspecting insect. They ‘ve been known to jump 10 to 40 times their body length. To protect themselves, they will spin a line of silk as a “life-line” that allows them to dangle instead of plunging into oblivion if they fall after jumping.

Jumping spiders have extraordinary vision due to their four pairs of eyes, with the largest pair in the front of their face. These give them an almost intelligent appearance. You can see them follow their prey, your finger or a stick that approaches them. Their sight is so good that they can supposedly identify their prey up to a foot away, some even as much as eight feet away!

Phidippus jumping spiders are the specific type of jumping spiders that area residents most often encounter. They tend to be large, hairy, stout, short-legged beasts. These nimble spiders are able to easily walk both sideways and backwards as well as forwards… and to some they resemble small tarantulas. A Phidippus audax, the daring or “three-spot” jumping spider, is probably the most common jumping spider in our area. It’s black in color with three white spots on the top of its body. It’s two front mouthparts or “chelicerae” at the front of its head are an iridescent green.

With their exceptional hunting and attack abilities, jumping spiders don’t spin cobwebs. However, they may make a silken tube or shelter in which to molt, lay eggs, or overwinter. While jumping spiders might appear quite fierce, they’re considered harmless. They may react to disturbances or threats by biting, but reactions vary between a minor skin irritation to no reaction at all. Jumping spiders are most often found in open places, such as on tops of low garden plants, on walls and fences, and decking.

I once had a pair of Phidippus audax take up residence in a pleated lampshade in my living room. I fondly dubbed them “Lucy and Ricky” . They would come out during the day and early evening to catch any bothersome flies, other insects, and spiders that occasionally came close. This couple of jumping spiders provided excellent control of these undesirable insect house guests.

While many of you probably shudder at the thought of sharing your residence with a pair of hairy black spiders, you might want to reconsider. Phidippus spiders have been observed attacking and killing hobo spiders…. one of the poisonous spiders encountered in our area. So while the jumping spiders may look like a scary foe, they should be considered a beneficial friend that can help keep the true pests under control.

Sac Spider: While the hairy Phidippus looks rather fierce, the sac spider appears innocuous. The venomous sac spider species found in our area is Cheiracanthium inclusium. It’s light olive green to yellow white in color. It’s a small spider, only one quarter inch in length, that doesn’t appear very menacing. They’re most commonly found outdoors, but have been known to come indoors especially in the fall months. Outdoors, the sac spider spins tubular nests in cracks and crevices or under bark and other plant debris. These tubes are open at both ends. Indoors it spins a small silken “sac” web in corners, behind things or lives in wall voids. You’ll most commonly see it running on ceilings and walls, but it will quickly drop to the floor if disturbed. Symptoms of their venomous bite can include local pain, nausea, and severe muscular discomfort that lasts several hours.

Treating a Spider Bite: If you’re bitten by a spider, first apply an antiseptic to the bite site to prevent infection. If there’s pain or swelling accompanying the bite, apply an ice pack. If you suspect you’ve been bitten by a black widow, hobo, or sac spider have someone take you to see a physician. If at all possible, bring the attacking spider with you. Doctors will not administer anti-venom for black widow spiders unless there’s proof that a black widow was the offending spider. You should also contact a physician if you receive a bite that causes a severe or unusual reaction, even if you don’t know it was caused by a poisonous spider.

Next week: Good “Fillers” for Container Gardens

Published: 5/15/2004 2:26 PM

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