Are Nursery Web Spiders Poisonous? Debunking Myths & Facts

Nursery web spiders are fascinating creatures that can be found near water edges and on shoreline vegetation.

These large spiders may appear intimidating, but many people wonder if they are actually poisonous to humans.

While nursery web spiders do possess venom, it is primarily used to kill their prey – including small fish.

However, the venom is not potent enough to pose a significant threat to people or pets.

So, despite their somewhat fierce appearance, nursery web spiders are not considered dangerous to most humans.

Are Nursery Web Spiders Poisonous?

Venom and Toxicity

Nursery web spiders belong to the family Pisauridae and do possess venom, which they use to immobilize their prey¹.

However, their venom is not considered dangerous or toxic to humans. Compared to other venomous spiders, nursery web spiders pose a minimal threat.

Bite Effects on Humans

Bites from nursery web spiders are rare occurrences. When bites do happen, they are usually the result of the spider feeling threatened or disturbed².

The effects of a nursery web spider bite on humans are typically mild and may include:

• Temporary pain or discomfort
• Slight redness or swelling at the bite site

Generally, these symptoms subside within a short period without any long-lasting complications³.

Comparison Table

Characteristic	Nursery Web Spiders	Other Venomous Spiders
Venomous	Yes	Yes
Dangerous to Humans	No	Depends on the species
Bite Symptoms	Mild	Varying degrees of severity

Bite Effects – Key Points

• Nursery web spiders have venom
• Their venom is not considered dangerous to humans
• Bites are rare and typically result from disturbance or threat
• Bite symptoms include temporary pain, redness, or swelling
• Symptoms usually resolve quickly without complications

Nursery Web Spider Biology and Behavior

Physical Characteristics

Nursery web spiders belong to the family Pisauridae. They have slender bodies and long legs, which help them blend in with plants or grass stalks.

Their size varies depending on the species, but they are generally medium to large-sized spiders.

Their bodies often have lengthwise striping in colors including shades of brown, black, gray, and white. Their carapace and chelicerae display various shades of brown or gray.

Habitat and Distribution

These spiders can be found in a variety of habitats, including:

• Grasslands
• Woods
• Climbing on plants near water

Nursery web spiders are mainly distributed in North America. They are adaptable to different environments, which allows them to occupy diverse habitats.

Diet and Hunting Strategies

Nursery web spiders’ primary diet consists of insects. They employ different hunting strategies, such as:

• Ambushing: They wait for their prey on plants or grass stalks.
• Jumping: They can jump to catch flying insects like flies.

These spiders don’t spin webs to catch prey, which distinguishes them from other species like funnel web spiders and orb weavers.

Comparison between Nursery Web Spider and Wolf Spider

Feature	Nursery Web Spider	Wolf Spider
Web construction	Minimal, nursery web only	Minimal, no elaborate web
Active at	Daytime	Daytime and primarily nighttime
Body markings	Lengthwise striping	Varied, some may have striping
Hunting strategy	Ambushing and jumping	Stalking, chasing, grabbing prey
Care for offspring	Build protective nursery web	Carry young on their back

Nursery web spiders exhibit fascinating behaviors related to reproduction. Female nursery web spiders build a protective nursery web to house their offspring.

The male nursery web spider often presents the female with a gift-wrapped insect as part of their courtship ritual before mating.

This behavior has not been observed in wolf spiders.

Reproduction and Life Cycle

Mating and Courtship Rituals

Nursery web spiders, specifically Pisaurina mira, have quite unique mating rituals.

The male nursery web spider offers the female a “gift” to increase his chances of successful mating.

The gift, typically a captured insect, is wrapped in silk and presented to the female spider.

During courtship, both spiders perform intricate behaviors which may involve:

• Tapping on each other’s legs
• Vibrations through the web
• Confined movement around each other

Egg Sac and Parental Care

Female nursery web spiders exhibit exceptional parental care. After mating, the female will lay her eggs and create a protective egg sac.

They carry the egg sac with their fangs until it’s about to hatch. Key features of egg sac and parental care:

• Female spiders create a cocoon-like structure called a “nursery” by weaving silk around leaves or shrubs
• The nursery protects spiderlings from predators and harsh environmental conditions
• Spiderlings stay in the nursery for a short period after hatching, then disperse to find their own territories

Nursery web spider bites are generally not dangerous to humans. However, they may cause localized pain and swelling.

Comparison between Pisaurina mira and Dolomedes (raft spiders):

Feature	Pisaurina mira	Dolomedes
Parental Care	High	Moderate
Active Hunters	Yes	Yes
Habitat	Land, shrubs	Near water
Courtship gift	Yes	No
Sunbathing	Yes	No

Overall, nursery web spiders are fascinating creatures with unique courtship rituals and a strong parental instinct. Although their bites can be painful, they are generally harmless to humans.

Surviving and Avoiding an Unwanted Encounter

Do’s and Don’ts Around Nursery Web Spiders

Nursery web spiders belong to the family Pisauridae and are commonly found in the woods or near their habitat.

These spiders are not toxic to humans, but it’s still best to practice caution when you come across them. Here are some do’s and don’ts:

• Do observe them from a safe distance, as they might feel threatened if you come too close.
• Don’t disturb their habitat or try to handle the spiders directly.
• Do keep your outdoor areas well-maintained to minimize spider encounters.
• Don’t panic if you come across a nursery web spider. Remember, they pose no significant threat to humans.

First Aid for Nursery Web Spider Bites

Although nursery web spiders are not toxic, their bites can be painful and might cause an allergic reaction in some individuals. If you are bitten, follow these steps:

1. Clean the bite area with soap and water.
2. Apply a cold compress to reduce swelling.
3. Avoid scratching or rubbing the area, to prevent infection.
4. Take over-the-counter pain relievers and antihistamines for relief.

Here is a comparison table of some features of nursery web spiders versus other common spider species:

Feature	Nursery Web Spider	Brown Recluse	Orb Weaver
Toxic to humans	No	Yes	No
Habitat	Woods, near water	Dark, secluded areas	Gardens, near plants
Molting	Yes	Yes	Yes

Remember, nursery web spiders are a part of our ecosystem and play an essential role in controlling the population of other insects. Treat them with care, and maintain a safe distance to avoid any unwanted encounters.

Footnotes

1. Nursery Web Spider (Family Pisauridae) – Field Station ↩

2. Spiders in and Around Homes | NC State Extension Publications ↩

3. Spider Management Guidelines–UC IPM ↩

Conclusion

To wrap things up, when it comes to nursery web spiders, they do have a kind of poison they use to catch their food.

But this poison isn’t dangerous to people.

These spiders have fascinating maternal instincts that are seldom found in the animal kingdom.

Knowing about their lack of poison and their role in nature can help keep them from harm and you safe.

Just remember, like with any spider, it’s good to give them their space and not bother them.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about nursery web spiders. Scroll down to have a look at some of them.

Letter 1 – Nursery Web Spider from South Africa

Subject:  What spider is this carrying it’s egg sac?
Geographic location of the bug:  Robertson, Western Cape, South Africa
Date: 08/13/2018
Time: 12:19 PM EDT
Your letter to the bugman:  Hi there,
We were wondering if you could tell us what kind of spider this is carrying it’s egg sac?
Thanks!
How you want your letter signed:  Pearce

Dear Pearce,
We can narrow this identification down to the family, but we cannot say for certain that we know the genus or species. 

There are two families of Spiders where the female carries about the egg sac.  Wolf Spiders in the family Lycosidae drag the egg sac from the spinnerets while Nursery Web Spiders, including Fishing Spiders, in the family Pisauridae carry the egg sac in the chelicerae or fangs. 

Your individual is a Nursery Web Spider.  According to BioDiversity Explorer:  “All pisaurids construct a round white egg case that is carried under the sternum held in the chelicerae (jaws). This causes them to assume a tiptoe stance. Just before the eggs are due to hatch, the female constructs a nursery web around the egg case.

This is attached to the vegetation with a supporting web around it. The spiderlings leave the nursery after one or two moults.” 

Wikimedia Commons has an image that looks very much like your individual, and it is identified as Chiasmopes lineatus, but there are no images of that genus on BioDiversity Explorer. 

The only other representative of the genus we could find is on Project Noah, but it is a much thinner and smaller male.

Letter 2 – Nursery Web Spider (Dolomedes) with eggsac

fishing spider ?
Hi,
Just logged onto your neat site. I think I have a fishing spider here, but not sure what it’s carrying. Can you help me out.
Thank you, Al Chartier

Hi Al
Fishing Spiders in the genus Dolomedes belong to the larger Family Pisauridae, the Nursery-Web Weavers.

The female spiders, according to Comstock: “From the time the egg-sac is made until the spiderlings are ready to emerge, the mother carries about with her, wherever she goes, this great silken ball with its load of eggs or of young. the difficulty of doing this can be seen by a glance at … [your photos].

The egg-sac is held under the body; and is so large thaqt the mother is forced to run on the tips of her tarsi in order to hold the load clear of obstructions. … Just before the young are ready to emerge from the egg-sac, or just after they begin to do so, the mother fastens it among leaves at the top of some herbaceous plant or at th end of a branch of a shrub, and builds a nursery about it by fastening the leaves together with a network of threads.

She then remains on the outside of the nursery guarding the young.” Thank you for your wonderful contribution to our site.

Letter 3 – Nursery Web Spider: Mama and Brood

Great Nursery Web Shot!
I know I’m becoming a pain in the patootie, but your website is the reason I’m less disgusted and more interested in insects than ever before, and I just had to share these great photos with you.

I stumbled upon this tangle of babies in the bush in front of my house in Upstate New York, and then found the momma Pisaurina mira sitting behind the kids! I ran and got my camera immediately.
She was a real big one, too!
Liz

Hi Liz,
Your photos are truly spectacular. Just don’t try to bother Mama spider’s brood as she will get very defensive.

Letter 4 – Nursery Web Spider carrying Egg Sac

What is this wolf spider carrying? Are these eggs?
Lisa

Hi Lisa,
Your female spider is carrying an egg sac, but we are not convinced she is a Wolf Spider. We think she is a Nursery Web Spider, Pisaurina mira, but without the often seen stripe running down the back.

The band is sometimes absent. She will eventually construct a Nursery Web where she will place the egg sac and then remain to guard it.

Wolf Spiders also exhibit maternal tendencies, but they drag the egg sac from silken threads attached to the spinnerettes and then carry the newly hatched spiderlings on their backs.

Nursery Web Spiders carry the egg sac in the chelicerae, the mouthparts.

Letter 5 – Nursery Web Spider from Kenya

More spiders
Location: Masai Mara, Kenya
December 22, 2010 5:30 am
Hi Bugman,
More spider close-ups from Kenya!
…
Picture 2: A Crowned Nursery-Web Spider (Rothus purpurissatus)from the family Pisauridae.
Nursery-Web males must bring a food-gift to the female before she will mate with him.

They then build a web specifically for holding the eggs and baby spiders (hence the name Nursery-Web).

Once the babies have left the web, the female eats the web and regains a percentage of the protein from the silk.
…
Signature: Zarek

Hi Again Zarek,
As we continue to post the numerous images you have sent to us, we are reminded that despite being separated by an ocean and the equator, your description of a Crowned Nursery Web Spider’s mating habits is quite similar to related species in the family Pisauridae that live in North America.

Letter 6 – Nursery Web Spider from Scotland guarding her Nursery Web

Spiders
Location: Perthshire Scotland
April 3, 2012 2:38 am
Was wondering is you could identify these pictures taken in an old established oak wood on stinging nettles. Pictues taken in July.
Many thanks.
Signature: D H Todd

Dear D H Todd,
The general shape of your spider and the web she has spun reminded us so much of the North American Nursery Web Spider, Pisaurina mira that we had no trouble identifying your spider as a related Nursery Web Spider, Pisaurina mirabilis, on the UK Safariwebsite. 

UK Safari lists the habitat as:  “Usually found low vegetation especially nettle beds.” 

Nursery Web Spiders are among the most maternal spiders and they exhibit very protective behavior regarding their eggs and the newly hatched spiderlings. 

UK Safari describes the behavior as:  “After mating, the female Nursery web spider lays her eggs into a silk cocoon which she carries around in her fangs. 

Just before the eggs hatch, she spins a silk tent (nursery web) and releases her spiderlings inside it.  This tent offers them some protection for the first few days of their life. 

After their first moult they leave the tent.  The female stays close to the tent until all the spiderlings have dispersed.”

Letter 7 – Nursery Web Spider might be WhiteBanded Fishing Spider

Majestic Spider
Location: Tunica Falls in Mississippi
May 11, 2012 11:07 pm
My friend and I stumbled upon this spider when we were on a hiking trip. She nearly walked right into it! It was huge and very fuzzy, but as you can tell from the picture, also very beautiful.

I don’t know much about spiders , but I’ve never seen one like this. I’d really like to know what kind it is. Thanks!
Signature: curious hiker

Dear curious hiker,
We are relatively certain that this majestic spider is one of the Nursery Web Spiders in the family Pisauridae, a group known for the pronounced maternal care of the eggs and young spiderlings, however, we are not certain about the species. 

We believe this is a member of the genus Pisaurina because of the white markings, however, there are some inconsistencies including the jagged line to the markings on the abdomen and that the markings seem to circle the head area as opposed to being more like stripes. 

We would not entirely overrule that this might be one of the Fishing Spiders in the genus Dolomedes like the Six Spotted Fishing Spider. 

Here are two photos from BugGuide for comparison:  Pisaurina brevipes and Pisaurina mira.  We will try to get another opinion.

Eric Eaton responds
Daniel:
I’m pretty certain it is a Dolomedes, but after that I’m not positive.  Lots of variation in markings in that genus.  Mississippi would be where a lot of species overlap in range, too.
Eric

Update:  May 12, 2012
We think a very likely candidate might be the White Banded Fishing Spider, Dolomedes albineus.  This photo on BugGuide shares many similarities and the description on BugGuide reads:  “Generally an ID can be made by the white band along the ‘face’ (clypeus).”

Letter 8 – Nursery Web Spider called “Truly awful”

Subject: Truly awful spider
Location: Eastern PA
May 20, 2013 5:47 pm
This was spotted on a warm morning in May in Pennsylvania, in a flat space between a gate and the post it goes up against. It was identified (I think incorrectly) at brown recluse spider. Any idea what this guy is?
Signature: Joe

Joe,
You should be ashamed of yourself calling this Nursery Web Spider “Truly awful.”  Nursery Web Spiders, which include Fishing Spiders, are along with Wolf Spiders among the best mothers in the arachnid world. 

The female Nursery Web Spider carries her eggs in her chelicerae or jaws and eventually finds a safe place when the eggs are getting ready to hatch. 

The safe place is often in a low tree or shrub and she spins a nursery web which she continues to guard.  We believe your Nursery Web Spider is Pisaurina mira.
P.S.  Here is a link to the Brown Recluse.

Letter 9 – Nursery Web Spider and Egg Sac

Subject: Spider
Location: Rhode Island , USA
July 11, 2015 2:03 pm
Is this a grass spider?
Signature: Kirsten

Dear Kirsten,
This is not a Grass Spider.  This pretty little lady is a Nursery Web Spider, Pisaurina mira, and she is carrying her egg sac.  Nursery Web Spiders are harmless, and not aggressive except when defending their young. 

The female Nursery Web Spider has very strong maternal instincts, and she carries her egg sac with her until she finds an appropriate place to leave it. 

She then spins a nursery web and continues to guard the eggs and the young until they are ready to disperse. 

Nursery Web Spiders are hunting spiders that do not build a web to snare prey.  The sole purpose of the web is for a nursery.

Hi Daniel!
Thank you so much for this information … Glad to know she is not aggressive despite her intimidating size.

I did not kill her, but did gently relocate her with a garden rake( I really needed the length as I fear spiders) ,and she held on to her egg sac , into some woods behind my house.

Hope she can find a nice place away from my chair lounger!
Thanks!
Kirsten

Letter 10 – Nursery Web Spider from Panama, we believe

Subject: Giant Crab Spider? Panama
Location: Darien, Panama
April 13, 2017 6:18 am
Is this a Giant Crab Spider (Sparassidae)? I found it on rocks in an almost-dry stream bed in Darien, Panama on March 27th (dry season).
Signature: Peter H

Dear Peter,
This looks more like a Nursery Web Spider in the family Pisauridae to us.  We will attempt additional research.  Members of the family known as Fishing Spiders are frequently found near water.  Here is a similar looking individual from Honduras on Arachnids My Species.