{"id":343920,"date":"2025-12-14T15:49:17","date_gmt":"2025-12-14T15:49:17","guid":{"rendered":"https:\/\/peraltafinancing.com\/uncategorized\/pest-control-blog-guardian-pest-solutions-3\/"},"modified":"2025-12-14T15:49:17","modified_gmt":"2025-12-14T15:49:17","slug":"pest-control-blog-guardian-pest-solutions-3","status":"publish","type":"post","link":"https:\/\/fivemor.com\/?p=343920","title":{"rendered":"Pest Control Blog | Guardian Pest Solutions"},"content":{"rendered":"


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August 31, 2020<\/strong><\/p>\n<\/header>\n

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Tarantular, my pet Chilean rose tarantula (Grammostola rosea<\/em>), chowing down on a cockroach. As an illustration of how long spiders can go between meals, this was the most recent meal she accepted, and I offered it to her 16 months ago. She has been turning down food since. PC \u2013 Liz Cambron<\/figcaption><\/figure>\n

Spiders are a common concern for our clients\u2026 but
\nshould they be? Spiders are a diverse group, having roughly 48,000 species distributed
\naround the globe (excluding Antarctica). Defining features of the group include
\neight legs, subchelate (fanged) mouthparts that are usually venomous, a narrow connection
\nbetween the body sections, silk glands on the abdomen, and (usually) an
\nunsegmented abdomen. Even though most spiders are venomous, relatively few are
\nmedically significant (i.e. harmful enough to humans to warrant medical
\nattention). As a general rule, spiders are predominantly carnivorous, feeding
\non insects and other small animals. Most spiders have poor vision and rely
\nprimarily on their sense of touch to navigate the world, but a few \u2013 such as
\njumping spiders, wolf spiders, and ogre-faced spiders \u2013 have enlarged eyes and
\nkeen vision. In most situations, spiders are beneficial for their role in
\nlimiting populations of their prey insects, yet people tend to not find them
\nrepulsive. So I\u2019m going to try to educate on spiders so that you can see them
\nas I do \u2013 as adorable leggy fuzzballs that make the world a better place. <\/p>\n

While it does not follow natural groupings or
\nsystematics of spiders, I\u2019m going to lump them into useful groups of common
\nspecies for the purpose of this discussion. <\/p>\n

Indoor web-spinners<\/strong><\/p>\n

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This cellar spider changed took advantage of poor ventilation in a college dorm room and built her web in a ceiling corner in the bathroom shower. It must have been a productive spot, because she\u2019s holding an egg sac in her jaws. PC \u2013 Jamie Kopco<\/figcaption><\/figure>\n

By far, the most common indoor web spinners are
\nthe cellar spiders (family Pholcidae) and the comb-footed cobweb weavers
\n(family Theridiidae). Cellar spiders can be recognized by their distinctively
\nlong, thin legs, and they often have an elongate abdomen. Their webs are relatively
\nscantly constructed cobwebs with very thin strands that can be nearly invisible\u2026
\nunless they collect dust. Whereas most spiders build a web to a suitable size
\nto catch enough prey and maintain it at that size, cellar spiders often build
\nexpansive networks of webs, adding onto the edge of a web to make up for old
\nstrands wearing out and losing their stickiness. As a result, cellar spiders
\nare responsible for the cobwebs that come to mind when you imagine a haunted
\nhouse. They usually build their webs near an overhang, which may be a ceiling
\nor roof, or could be within cracks or crevices or inside open containers. Their
\ncobwebs are effective at catching flying insects, and they also have a
\nreputation for effectively preying on other spiders. The comb-footed cobweb
\nweavers, on the other hand, have shorter legs and usually have nearly spherical
\nabdomens. The cobweb is tangled and dense, with thick, strong strands. It is virtually
\nalways constructed near the ground, and high-tension prey-capture strands
\nrunning from the web to the ground below make an effective trap for crawling
\ninsects. Both of these spiders require high humidity, and most often colonize
\ndamp or poorly-ventilated areas such as garages, basements, and crawlspaces. <\/p>\n

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One of the comb-footed cobweb weavers that took on a carpenter ant nest in my garage. She and six or seven others wiped out the carpenter nest in two or three weeks. Here, she proudly hangs in her web as one of her four egg sacs hatches. The dark debris on the floor in the background is hundreds of carpenter ant carcasses sprinkled with spider droppings. PC \u2013 Jamie Kopco <\/figcaption><\/figure>\n

Outdoor web-spinners<\/strong><\/p>\n

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At least one orb weaver has achieved fame \u2013 Charlotte A. Cavaticus. Based on the barn orb weaver, Araneus cavaticus<\/em>, many aspects of Charlotte\u2019s life history were accurately conveyed in the book. While there is no scientific evidence that spiders ever befriend swine, they probably don\u2019t object to the associated flies. <\/figcaption><\/figure>\n

While the \u201cindoor\u201d web-spinners can sometimes be
\nfound outside in rock piles, caves, and other protected environments, many
\nweb-spinning spiders routinely stay outside. The most familiar of these are
\nprobably the orb weavers in the families Araneidae, Tetragnathidae, and
\nNephilidae. Each of these spider families contain species that spin the
\nfamiliar spiral-pattern web often depicted as a \u201cstandard\u201d spider web.
\nNephilids are large to massive spiders whose webs often span several feet; they
\nare common in the southeastern United States, but are not found in the upper Midwest.
\nTetragnathids tend to be far smaller, often constructing horizontal or slanted
\norb webs less than a food across. Some species are particularly common on docks
\nand vegetation overhanging water, and can be recognized by their slender,
\nelongate body shape and extra long chelicerae (mouthparts). Araneids are the most
\ncommon and conspicuous orb weavers, with females of the largest species growing
\nup to an inch or so in body length (not counting the legs). Araneids replace
\nthe prey-capture strands daily, with diurnal species rebuilding at dawn and
\nnocturnal species rebuilding at dusk. Diurnal species are often brilliantly
\ncolored in contrasting patterns of silver, black, and yellow, while nocturnal
\nspecies tend to be drab brown, but may be yellowish or orange. All of the orb
\nweavers\u2019 webs are best at catching flying insects, and they often string up
\nwebs in front of outdoor lights to catch the swarms of insects that are
\nattracted by the light. <\/p>\n

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Grass spiders, like this Agelenopsis<\/em> have a similar body shape and coloration to wolf spiders, but can be distinguished by their eye pattern, long spinnerets, and web-building behavior. PC \u2013 Judy Gallagher, via Wikipedia<\/figcaption><\/figure>\n

Grass spiders are another common outdoor web-spinner.
\nThese spiders spin dense sheet-like webs with a funnel-shaped retreat on a side
\nor corner. The webs are often built on shrubs or grass, or in wall corners.
\nUnlike most web-spinning spiders whose webs have sticky prey-capture strands,
\ngrass spider webs are not sticky and primarily serve as vibration sensors that
\nallow the spider to detect when prey is walking nearby, with the spider relying
\non extreme speed to capture insects that fall or crawl onto the web. Grass
\nspiders do sometimes wander indoors, but they rarely survive long in the drier
\nenvironment of a typical home. Grass spiders are often mistaken for wolf
\nspiders, but can be distinguished by their uniformly small eyes, long
\nspinnerets, and the fact that they spin webs. <\/p>\n

Big, hairy spiders<\/strong><\/p>\n

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Note the enlarged posterior median eyes that are distinctive of this beautifully patterned wolf spider. PC \u2013 Rafael Poupon, via Wikipedia<\/figcaption><\/figure>\n

The most common and well-known of the \u201cbig, hairy
\nspiders\u201d in the upper Midwest are the wolf spiders and fishing spiders, though some
\nground spiders fit this group too. These are large, dark-colored, often hairy
\nspiders that hunt rather than producing prey-capture webs. Wolf spiders can be
\nrecognized best by their eye pattern; the entire anterior row of eyes and
\nposterior lateral eyes are all small, while the posterior median eyes are
\nenlarged and highly reflective like cat or raccoon eyes. They tend to be dark
\nbrown as a ground color, but often have lighter lengthwise stripes along the
\nbody. They make up a large diverse family that includes burrowing ambush
\nhunters and active prey searchers. By spiders standards, they tend to be less
\nthan stellar climbers and spend most of their time on the ground. <\/p>\n

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I made this fishing spider, Dolomedes tenebrosus<\/em>, into the Ecology Area mascot when I worked at a Boy Scout camp in high school. She\u2019s so plump because she\u2019s very well fed, plus this picture was taken a few weeks before she produced an enormous egg sac. She and her brood were released unharmed at the end of the summer. PC \u2013 Jamie Kopco<\/figcaption><\/figure>\n

Fishing spiders are among our largest spiders,
\nespecially if measured by leg-span. They are often mistaken for wolf spiders,
\nbut tend to be brown with black blotches rather than brown with light stripes.
\nOther differences include uniformly small eyes and a more sprawled-out posture in
\nthe fishing spiders than the wolf spiders. Fishing spiders tend to be ambush
\nhunters, and often perch head-down on vertical objects like dock pilings or
\ntree trunks to strike insects that pass below. Large fishing spiders are also
\nable to snatch small fish and tadpoles from water. <\/p>\n

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Another scout camp specimen, this is a fairly average-sized ground spider. PC \u2013 Jamie Kopco<\/figcaption><\/figure>\n

Ground spiders are usually medium-sized,
\ncomparable in size to the medium-to-small wolf spiders. They are often dark
\ncolored, with black and dark red figuring prominently in their color scheme,
\nthough some species have vibrantly contrasting black-and-white markings. The
\nblunt-tipped spinnerets are their best distinguishing feature. Ground spiders often
\nhide well enough to never be seen, even if they do live in your yard. <\/p>\n

Little hunters<\/strong><\/p>\n

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A small jumping spider that I found in Pennsylvania. It was only around 1\/4\u2033 long. PC \u2013 Jamie Kopco<\/figcaption><\/figure>\n

Several smaller types of spider are also
\nfree-roaming hunters; jumping spiders, sac spiders, and crab spiders fit into
\nthis grouping. Jumping spiders are, in my opinion, the cutest and most
\ncharismatic of the spiders. Immediately recognizable by their enormous anterior
\nmedian eyes, jumping spiders are very visual and can often be observed turning
\nto look around. They are also commonly considered to be the most intelligent of
\nthe spiders, and they will often make eye contact with you if you observe them
\nclosely enough. They hunt like tiny, 8-legged panthers, stealthily creeping up
\non prey until they get within pouncing distance. Jumping spiders are excellent
\nclimbers, and may be found roaming the inside of windows to hunt flies that
\nbecome trapped inside. <\/p>\n

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Sac spiders look like they need to get more sun. This particular individual is actually dark-colored by sac spider standards. PC \u2013 Jamie Kopco<\/figcaption><\/figure>\n

Sac spiders are small to medium-sized and tend to
\nbe pale yellowish in color. They get their name for spinner little silk \u201csacs\u201d
\nthat they rest in. Despite their small size, these spiders can be somewhat
\ndefensive, and their bites have been implicated in minor<\/em> necrotic
\nlesions, though it is unclear whether the lesions are a reaction to the spider\u2019s
\nvenom or a bacterial infection that establishes in the bite wound. <\/p>\n

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When camouflaged on a flower, sometimes the easiest way to spot crab spiders is by backtracking from the prey they\u2019re holding. PC \u2013 Alvesgaspar, via Wikipedia<\/figcaption><\/figure>\n

Crab spiders come in several different varieties. All
\nof the crab spiders hold their front legs at an angle, with the \u201ctop\u201d of the
\nleg angled backward. The thomisid crab spiders really earn the \u201ccrab\u201d name,
\nwith the first four legs far larger than the rear four and usually held aloft
\nso they look like crab claws. Some of the thomisid crab spiders are brightly
\ncolored \u2013 usually white, yellow, or pink \u2013 and sit on or near flowers to ambush
\npollinators. Others are mottled brown and camouflaged, and ambush crawling
\ninsects on the ground. The philodromid crab spiders, also known as \u201crunning
\ncrab spiders\u201d are small brownish or grayish spiders. The front four legs are
\nslightly longer than the back four, but the difference is subtle and the
\nspiders rest with on all eight legs rather than holding the first four aloft
\nlike in the thomisid crab spiders. Finally, the giant crab spiders, also known
\nas huntsman spiders, are very large spiders (typically larger than fishing
\nspiders), but are not found as far north as the Midwest \u2013 though they can be
\nfound across the southern United States. <\/p>\n

Oddball spiders<\/strong><\/p>\n

Two spiders are worthy of mention, not because of
\ncommonness, but because of weirdness. The spitting spiders are a family of
\nsmall spiders that primarily hunt other spiders. Their high-domed head houses
\nenormous glands that produce a cocktail of venom and silk that the spider can
\nfire from its fangs. The mixture leaves the fangs as a liquid, solidifying as
\nit flies, then rapidly contracting after hitting its target. That means that
\nthe sticky concoction binds the target in self-tightening strands of silk,
\nwhich are infused with venom to help subdue the prey. <\/p>\n

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That funky \u201chelmet\u201d shaped head has room for the giant venom glands and muscles needed for this oddball spider to \u201cspit\u201d to subdue prey. Don\u2019t let the macro fool you though \u2013 these are small to tiny spiders. PC \u2013 Oren Auster<\/figcaption><\/figure>\n

The other oddball is the woodlouse hunter, Dysdera crocata<\/em>. This medium-to-large spider is a unique specialist predator of woodlice, otherwise known as isopods, sowbugs, pillbugs, rolly-pollies, or potatobugs. It has a reddish head, legs and fangs, pale grayish abdomen, and appears mostly hairless. The most eyecatching feature of this spider is its enormous fangs, which it needs to grip woodlice and penetrate their sturdy exoskeletons. It featured in a blog post all its own<\/a>, so check out that post if you want more info. <\/p>\n

Do-not-touch spiders<\/strong><\/p>\n

While most spiders pose no hazard to humans,
\nhaving venom too weak to affect such a large animal and often having fangs too
\nsmall to pierce the skin, some species are potentially dangerous. Globally, the
\nmedically-significant species of which I am aware include the Australian
\nfunnel-web spiders (not to be confused with our grass spiders, which are also
\nsometimes called funnel-web spiders), some species of South American wandering
\nspiders (note \u2013 wandering spiders are a big family, and only some species are
\ndangerous), widows, and recluses. Despite having powerful enough venom to
\nsicken a human, these spiders still tend to prefer avoiding confrontation and
\ntend to be reluctant to bite. Of those, the United States is home to five
\nspecies of widow (Northern, southern, western, brown, and red) and several
\nspecies of recluse, with the brown recluse being the most well-known for its
\nrelatively broad distribution and tendency to cohabitate with people. <\/p>\n

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An adult female western black widow, showing the characteristic glossy black coloration with red hourglass mark on the belly. PC \u2013 Ken-Ichi Ueda<\/figcaption><\/figure>\n

Widow spiders belong to the comb-footed cobweb
\nweaver family discussed as common indoor spiders. The western and southern
\nwidows are not typically found in the Midwest, but sometimes stow away and are
\naccidentally introduced. Western widows turning up in grocery store produce
\naisles are not unheard of, as the irrigated farms of California create a
\nhospitable environment for them. The northern widow is naturally found throughout
\nthe entire northern half of the US and into Canada, but they seem to be very uncommon
\nacross their entire range. Brown and red widows are restricted to the southern US,
\nespecially Florida. The northern, southern, and western widows that
\nperiodically appear in the Midwest can be recognized by their globular abdomen
\nshape and predominantly glossy black color with a red hourglass shape on the
\nbelly. They may also have red spots or stripes on the back. Like other members
\nof their family, widows spin strong, dense cobwebs close to the ground. Their
\nvenom is neurotoxic, causing affected nerves to fire and muscles to cramp. This
\nmakes their bite acutely very painful, though dangerous medical complications
\nfrom their bites are actually very rare \u2013 even without medical intervention. <\/p>\n

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A very unexpected recluse that I found in Hudson, WI \u2013 though I have little doubt that he was a stow-away rather than part of an established population. Notice how remarkably unremarkable he looks. PC \u2013 Jamie Kopco (taken through a microscope eyepiece)<\/figcaption><\/figure>\n

Brown recluses are mostly found in the south-central
\nUS, with Missouri and Kansas being hot-spots and recluses becoming less common
\nas you venture north. The northern edge of their range cuts across Nebraska,
\nIowa, and Illinois, so brown recluses at their northernmost extreme overlap
\nwith Guardian\u2019s service area at its southern-most extreme. That being said,
\nbrown recluses can also hitchhike on objects moved by people, and I\u2019ve
\ncollected a brown recluse specimen in Hudson, WI last year (ID confirmed by PJ
\nLeisch at the WI Insect Diagnostic Lab). Brown recluses are almost
\ndistinctively plain spiders; the body color is almost entirely a neutral shade
\nof brown, though the abdomen may take on a darker or grayish hue, especially in
\nwell-fed spiders, and the head bears a darker \u201cfiddlehead\u201d shape, with the neck
\nof the fiddle pointing towards the spider\u2019s abdomen. The legs and abdomen lack
\nmarkings, spines, or bristles, but are covered in fine hairs. The eyes are
\narranged in three groups of two, which effectively distinguishes them from most
\nother spiders which have eight eyes arranged in two rows of four. Recluses have
\nproportionally small fangs and long, slender legs. Despite the abundance of
\ndistinctive characteristics that may be used to confirm a brown recluse
\n(especially three eye dyads), misidentifications are common. A huge variety of
\nspiders are brown, and many have markings that may be interpreted as
\nfiddle-head like on the head. Brown recluse bites are rare and usually mild,
\nrequiring no particular care beyond keeping the bite clean to prevent secondary
\ninfection. However, in some cases the bites result in the formation of a
\nnecrotic lesion at the bite site that can be slow to heal. <\/p>\n

How to manage spiders<\/strong><\/p>\n

How to manage spiders really depends on the type
\nof spider in question. One reasonable option is tolerance \u2013 after all, spiders
\nare beneficial arthropods that reduce populations of pest insects, and only a few
\nspecies of the thousands found in the United States are potentially dangerous
\nto humans. Shortly after starting work at Guardian, I watched a small community
\nof about seven or eight Parasteatoda tepidariorum<\/em> in my garage wipe out
\na satellite nest of carpenter ants over the course of a couple weeks. I would
\nargue that their efficacy was comparable to a professional carpenter ant
\ntreatment \u2013 but was far cheaper and posed no chemical exposure hazard. <\/p>\n

Web-spinning spiders are naturally sedentary, so physically relocating or killing individual spiders that place webs in problematic areas. Hunting spiders may inadvertently wander indoors while searching for prey, and are best excluded by sealing up cracks and crevices that allow them to enter. Spiders often struggle to survive with insufficient humidity, and I have never observed aggregations of cellar spiders or comb-legged cobweb weavers in dry environments. Therefore, using fans and\/or dehumidifiers to dry out an area may eliminate resident cobweb spiders. Another approach to managing spiders is to manage their prey supply; if insect prey are not available to support spider populations, then hypothetically the spider populations should decrease. However, many spiders can survive for weeks, months, or even years without food, so prey elimination should focus on not attracting spiders rather than eliminating them after they establish residence. De-cluttering a building can eliminate hiding places and web-building supports that favor spiders, and thorough vacuuming can physically remove large numbers of spiders. \u00a0Glue boards are also effective at intercepting hunting spiders and mate-seeking male web-builders. <\/p>\n

Data on the efficacy of pesticides<\/a> against spiders are sparse, but seem to indicate that the powerful organophosphate, carbamate, and organochlorine insecticides often used in agriculture are highly toxic against spiders. On the other hand, bacterial (e.g. Bacillus thuringiensis<\/em>) and botanical (e.g. neem extract, pyrethrins) as well as insect growth regulators seem to be ineffective against spiders, and pyrethroids seem to be hit-or-miss. Desiccating dusts seem to be effective in many situations, and microencapsulated lambda-cyhalothrin has been shown to be among the most effective pesticides against recluse spiders. However, pesticide applications are highly irritating to recluses, and increase both their movement and their proclivity to bite; therefore, a home treated for recluses should be vacated for at least 24 hours to allow remaining spiders to settle down. The same author who indicated that lambda-cyhalothrin is the most effective insecticide proposed that complete eradication of brown recluses may be impossible, so acknowledge that spider treatments may reduce spider numbers but are unlikely to completely eliminate them. Because of the human health hazards posed by effective products and the minimal threat posed by spiders, chemical control of spiders should probably be discouraged in most situations. <\/p>\n