The 23 Most Common SPIDERS in Iowa! (ID Guide)
What kinds of spiders can you find in Iowa?
Many people are terrified of spiders and find them extremely creepy. This is unfortunate because they are incredibly interesting creatures and crucial to our environment! Luckily, most spiders are harmless, and they control the insect population.
Today, you will learn about the most common spiders that live in Iowa.
Before we begin, note that the list below is just a fraction of the overall number of spiders found in Iowa. Because of the sheer number of these arachnids, it would be impossible to cover them all. With that being said, I did my best to develop a list of COMMON spiders that are often seen and easily identified.
23 Spiders in Iowa:
#1. Wolf spiders
Wolf spiders are one of the most recognizable spiders in Iowa!
They are found everywhere and in almost any habitat. I know that I see them often when flipping over rocks or logs. Unfortunately, there are so many individual species of wolf spiders that it would be impossible to list them here, especially since most look very similar.
Wolf Spider Range Map
Interestingly, wolf spiders do not make webs to catch their prey. Instead, they wait for an insect to walk by and then chase it down! Likewise, some species will make a burrow and then wait inside for dinner to walk by.
When it comes to arachnids, wolf spiders have incredible eyesight. They also have retroreflective tissue in their eyes, which produces a glow if you flash light at their faces.
Wolf spiders will bite if provoked, but their venom is not dangerous to humans. Bite symptoms are minimal and may cause itching, swelling, and mild pain.
#2. Cellar Spider
- Cephalothorax (head) and abdomen are different shades of brown.
- Less than a 1/2-inch (12.7 mm) body, 2-inch (51 mm) long legs, and the body is the shape of a peanut.
- Some species have 8 eyes, while others only have 6 eyes.
You know that spider that is always in the corners of your basement?
Well, it’s most likely a Cellar Spider! These long, thin, and delicate arachnids are commonly found in Iowa in homes and buildings. Whenever I clean my basement with a vacuum, a few of these spiders always seem to get sucked inside.
Cellar Spider Range Map
Cellar Spiders do something exciting when their web is disturbed by touch or has entangled large prey. They start vibrating rapidly, which has led to them sometimes being called “vibrating spiders.” They do this behavior to hide from predators or increase the chance of catching an insect that brushed up against their web.
Cellar Spiders are beneficial to have around because they have been known to hunt down and kill venomous spiders.
#3. Crab spiders
- On average, females measure 7–11 mm. Males are much smaller and range between lengths of 2–4 mm.
- Colors range widely based on the specific species. However, the most common colors are pink, yellow, white, green, or brown.
The best places to find crab spiders in Iowa are near flowers.
Crab spiders don’t use webs to catch their prey. Instead, they sit and wait inside flowers or other vegetation low to the ground for something to eat. Once a suitable victim comes by, they use their long forelegs to ambush it and make the kill. When insects are in short supply, such as during bad weather, they eat pollen and nectar to avoid starvation.
Lastly, many crab spiders have developed a mutualistic relationship with certain plant species since these spiders feed on and help deter harmful insects. Some plants even release an emission after being attacked that helps attract crab spiders in hopes they eat the intruder.
#4. Daring Jumping Spider
- Phidippus audax
Also called the Bold Jumping Spider.
- 4-14 millimeters long, black with white markings on the abdomen and legs.
- Eight eyes, but two are much bigger. Green metallic fangs.
- Sometimes they have orange marks on the abdomen when they are younger. As they get older, they turn white.
Daring Jumping Spiders can jump up to 50 times their body length.
But luckily, they are TINY spiders. Could you imagine if they were the size of a tarantula?
Daring Jumpers are hunting spiders that like open areas to stalk and chase down prey. They only make webs to protect their egg sac or to rest in at night. Interestingly, when they hunt, these spiders will spin one strand of webbing to use as a lifeline. They do this just in case their jump fails, as the strand of web acts like a bungee cord.
Daring Jumpers are common in fields and grassy areas. You will sometimes find them on fences or walls of outside structures because they like flat surfaces, and they point downward to make it easier on themselves to catch prey. Why work harder when you could work smarter?
#5. American grass spiders
- Both sexes are shades of brownish-black with stripes running from front to back.
- The abdomen is oblong and has two white stripes broken into sections.
- The head has a lighter stripe running down the middle, dividing the two dark stripes.
Grass spiders are one of the fastest spiders in Iowa.
Grass spiders are funnel weavers, which means they weave a funnel on one edge of their web. Their webs are not sticky, like other spiders. But once the silk is triggered, they use their speed to run quickly to get their prey.
Fortunately, they are harmless to humans. And they typically stay in their webs unless disturbed.
*The genus Agelenopsis consists of 14 species of grass spiders that live in North America.
#6. Black Widow
- Females are 6.35 mm to 9.5 mm long.
- Shiny black with a distinctive red hourglass-shaped mark. A row of red spots is sometimes visible above.
- Males are half the size of females but have longer legs.
Black Widows are the most venomous spiders in Iowa!
In addition, they are probably the most popular and recognizable spiders in the world. Almost everyone knows the red-shaped hourglass mark that appears on females.
And even though they have highly toxic venom that is 15 times stronger than a rattlesnake, they are not aggressive. The Black Widow only bites defensively if the web is disturbed, and they RARELY bite humans.
But, if you are one of the few unlucky people who are bitten each year, you should know that the venom affects your nervous system. Some people are only slightly affected by it, but many have a severe response. If you are bitten, the bite requires medical attention, and the neurotoxic venom can be fatal to small children if untreated.
#7. Furrow Spider
- Larinioides cornutus
Also known as Furrow Orb Spider or the Foliate Spider.
- Colors can vary from black to gray to shades of red.
- The abdomen is a very large smooth, oval shape.
- Lighter-shaded arrow markings on the abdomen point toward their head. Legs have a similar arrow pattern.
Furrow Spiders are found in Iowa in moist places, especially by water sources near grass or shrubbery. These arachnids don’t mind being by human structures either, like porches or corners of houses.
Did you know that spiders can’t hear? Furrow Spiders, like other species, actually use the hairs on their legs to sense sound.
Interestingly, these spiders make a new web every night. The reason for this is that they eat their web every single morning!
They rarely bite, but if bitten, you will only have mild pain and little discomfort.
#8. Black and Yellow Garden Spider
- Argiope aurantia
Also known as the Yellow Garden Spider.
- Both sexes have light-gray heads.
- Females are around 1 inch (25 mm) long. The abdomen has a wide black mark in the center and sides and is covered with yellow patches.
- The males are around .25 inches (6.3 mm) in length, not counting the legs.
- Legs start off orange or dark yellow close to their body and are mostly black toward the ends.
This species is one of the most recognizable spiders in Iowa!
Black and Yellow Garden Spiders make beautiful webs with a distinct circular shape of up to 2 feet (.6 m) in diameter. They are almost always found in sunny, open fields or gardens, as the name suggests. They are among the few species that make their webs in the daytime.
Look for a thick zigzag of silk in the center of the web called the stabilimentum (seen below). Some scientists think the zigzag mark helps to deter larger predators from running into it and destroying it. But other researchers think the stabilimentum reflects sunlight, which helps attract insects to the web.
Black and Yellow Garden Spiders are able to shake their web vigorously while remaining in the center of it. They do this to warn larger creatures to stay away and not run into the web. It also helps entangle insects before they get loose and fall off.
Despite their large size, these spiders are not aggressive. But they will bite if grabbed or provoked. However, the bite is harmless to humans, and the worse it can do is feel like a bee sting.
#9. Fishing spiders
They’re also known as Fishing Spiders, Raft Spiders, Dock Spiders, or Wharf Spiders.
- Both sexes can vary in color; some are brown, black, or cream-colored brown.
- Many species have a striking pale stripe down each side of the body; others have dots down the side of their body.
Fishing spiders are some of the largest spiders in Iowa.
Several different species are found here, and they are all large nocturnal spiders that find their prey around water. You’ll often see them on the docks by a lake during the day.
These arachnids have special short velvet-like hairs that don’t get wet, allowing them to stand or run on the water. They wait for prey to make a ripple, then race across the water to grab it. Most fishing spiders eat insects, but some species can catch small fish.
They can also hunt underwater because of their specialized lungs, which help them breathe while submerged. However, the air in their lungs makes them float, so they need to hold onto a rock or plant, or they will rise to the surface.
#10. American Nursery Web Spider
- Pisaurina mira
- They vary in color; some are shades of brown, and others are black.
- The brown ones can have a light tan body with a wide brown stripe down the middle.
- The black ones can have thick cream markings down the length of their body on both sides.
The Nursery Web Spider is best known for its odd mating behavior. Many female spiders are known to eat males after mating. To prevent this, the male ties up the female’s legs with his silk to avoid being eaten by the female.
These spiders typically live in Iowa in low shrubbery and high weeds. They prefer this environment because they like to stay hidden. They are known as ambush predators. They sit and wait for prey to come within reach, and then they attack with their chelicerae (claw-like pincers) and snatch them up.
#11. Common House Spider
- Parasteatoda tepidariorum
- Both sexes can appear anywhere from nearly black to a variety of colors.
- They sometimes have patterns of different colors on their body.
- Females are larger than males. Females also have a bulb-like abdomen that males lack.
These spiders are found in Iowa NEAR PEOPLE!
I know that I always find them in my garage! It always surprises me how small Common House Spiders are, as they are generally only between 5 and 6 millimeters long.
Even though there are probably a few in your house right now, you shouldn’t hate Common House Spiders. They are actually helpful because they feed on small insects and pests in your house, like flies, ants, and mosquitos.
They are relatively docile spiders, but bites do occur mostly due to their proximity to humans. But have no fear; their venom is not dangerous in the least.
#12. Bowl and Doily Spider
- Frontinella pyramitela
- Small, with a large, round, and shiny abdomen that is dark brown or black along the top with thick white vertical lines on the sides.
- White markings on the bottom of the abdomen. But the color can differ between spiders – some are dark yellow, and some have no color.
- The head is reddish-brown, legs are lighter brown, thin, and long.
Have you ever seen unique webs in shrubbery or hanging low in the woods?
If so, it was probably the web from the Bowl and Doily Spider. They are best known for their horizontal sheet webs that resemble a bowl, which are found in weedy fields or shrubs in all habitats.
Bowl and Doily Spiders build their sheet web between twigs and are only a few inches in diameter. The spider sits on the bottom of the bowl and waits for prey on the underside. Being on the bottom provides safety but also allows a surprise attack! Incredibly, they can bite their prey directly through the web!
Males seldom build webs, but they are known to cohabitate with females for long periods in their webs. As a result, it is common for multiple males to mate with the female, which causes sperm competition.
#13. Harvestmen (Daddy Longlegs)
- Colors vary; most are dull brown or dull gray, but some may be yellowish, greenish-brown, or reddish.
- Look for a dark blackish streak down the middle and sides.
- Single body region, only two eyes that do not see well.
“Daddy Longlegs” might be the most recognizable spider in Iowa!
We often see them in our yard, typically hiding underneath my kid’s playground or on rocks or logs. They are also very social, so you will often find them in large groups.
But even though Harvestmen look just like spiders, these arachnids are technically NOT spiders!
They are in the Order Opiliones, have no venom, lack fangs, and do not bite. In addition, Harvestman can swallow solid food, which allows them to eat small insects, fungi, dead organisms, bird dung, and other fecal matter. This differs from spiders that only eat their prey after turning them into a liquid.
As you might guess by their nickname, their legs play a vital part in their life. They use their legs for breathing, walking, smelling, and capturing prey. Males have longer legs than females, which they groom by licking. Seriously, you can watch this behavior in the video above!
#14. Spotted Orbweaver
- Neoscona crucifera
Also known as the Hentz Orbweaver, Spotted Orbweaver, and Barn Spider.
- Most often, these spiders are golden-orange or rusty-red.
- The legs have alternating dark brown and light brown bands.
- The abdomen is hairy.
These spiders are most often seen in Iowa in late summer and early fall.
Look for their large, orb-shaped web near lights, often constructed on buildings or other man-made objects. During the day, there is often a silken retreat that they retreat to for safety.
If you bother a Spotted Orbweaver, it will bite you in self-defense. But the venom is not dangerous to humans.
#15. Tan Jumping Spider
- Platycryptus undatus
Also called the Familiar Jumping Spider.
- Females are between 10 and 13 mm long. Males range from 8.5 to 9.5 mm.
- A tan, chevron-like pattern on their abdomens.
Tan Jumping Spiders are active and bold spiders, which makes them fairly common to see in Iowa. Look for them on vertical surfaces like walls, fences, and trees.
Jumping spiders don’t use webs to capture prey but instead HUNT smaller spiders and other invertebrates. Once their victim is sighted, they move slowly toward it until they are close enough to jump on and make the kill, similar to how a cat hunts.
The eyesight of jumping spiders is considered to be the best among invertebrates. They have eight eyes like most spiders, but the front two forward-facing eyes are incredibly large and tubular behind the lens. In addition, there are muscles behind the eyes that move and support the retina, which is unique to jumping spiders!
#16. Orchard Orbweaver
- Leucauge venusta
Orchard Orbweavers are easy spiders to identify in Iowa.
Seriously, look at their coloration, and you will see that it’s super unique!
First, the legs are leaf-green, although they can also be dark green or orange. But the top of the elongated abdomen is where they really stand out. Look for varying sizes of red, orange, or neon yellow spots!
This spider is timid and will not bite unless it feels threatened. Its bite is not dangerous to humans, but it may cause minor swelling and discomfort.
#17. Banded Garden Spider
- Argiope trifasciata
Also known as the Banded Orb Weaving Spider.
- This species has an oval abdomen and bright body markings. The back of the abdomen is pale yellow with silvery hairs and lateral bands of black stripes. Males are usually paler, sometimes even white.
- Adult females are around 13 to 14.5 mm long.
- Males are considerably smaller, reaching only a third of the females’ length.
The Banded Garden Spider builds an enormous web, typically around 23.6 in (60 cm) in diameter. The web itself is sticky and strong, able to hold very large insects like wasps and grasshoppers. One interesting feature of their webs is the so-called “stabilimentum,” a vertical zigzag pattern made from dense silk. Researchers think this feature is a way to attract insects that the Banded Garden spider eats.
Females usually rest at the center of the web, facing downwards. They face their webs east-to-west to take advantage of the rising and setting sun and hang in the center with their dark underside facing south. All this allows them to gain as much warmth as possible, enabling them to stay active later in the year.
These spiders rarely bite humans in Iowa and are not aggressive.
They may bite in self-defense if handled and bothered, but it’s unlikely that the bite would cause more discomfort than a bee sting.
#18. Marbled Orbweaver
- Araneus marmoreus
- A large orange abdomen with brown or black marbling, although they range in color (from yellow, white, black, brown, or red).
- Females grow up to 18 mm, with males being half that size.
- The legs are red with black and white banding beginning on the tibia.
Due to the large, orange abdomen, Marbled Orbweavers are often called “Pumpkin Spiders” and are fairly easy to identify. Look for these spiders in Iowa from mid-summer until the weather turns cold. The best places to find them are in moist, wooded areas along the banks of streams.
Their webs are oriented vertically, and Marbled Orbweavers attach a signal thread to the middle, which alerts them when prey has been captured. Unlike many garden spiders that sit at the center of their web, this species hides in a silken retreat constructed to the web’s side. They often hide under leaves or other debris they have stuck together with webbing, waiting patiently for a meal to get stuck.
#19. Zebra Jumping Spider
- Salticus scenicus
- Their anterior median eyes are large, which gives them excellent binocular vision.
- The coloration looks like a zebra; black with white stripes.
- Female spiders are 5–9 mm long, while males are 5–6 mm.
Zebra Jumping Spiders are found in Iowa in open, vertical habitats.
Rock faces and tree trunks provide good habitat, but they are also found in close proximity to humans on the walls of buildings and garden fences. You should also check the corners of the windowsills in your house, as they are sometimes found there too. 🙂
Jumping spiders don’t use webs to capture prey but instead use their incredible eyesight for hunting smaller spiders and other invertebrates. Once their victim is sighted, they move slowly toward it until they are close enough to jump on and make the kill, similar to how a cat hunts. Then, just in case they miss the target, they attach a silk thread to a surface so they can climb back up and try again!
To try and impress a potential mate, male Zebra Jumping Spiders will conduct a courtship dance by waving their front legs and pedipalps while also moving their abdomen up and down. A better dance increases the likelihood that the females will want to mate with the male. Males must be VERY careful when approaching the female; if the dance isn’t good enough, they risk being eaten.
#20. Broad-Faced Sac Spider
- Trachelas Transquillus
- Both sexes are small with a shiny dark brown or reddish color on the head.
- The abdomen is tan or gray with no shine but looks smooth.
Legs can be red, tan, or brown, with a darker front pair of legs compared to the other back legs.
Broad-Faced Sac Spiders are typically found in crevasses around houses or sometimes on windowsills. They are more common in houses as the weather outside turns colder.
Broad-Faced Sac Spider Range Map
They are nocturnal hunters that do not spin webs to catch prey. Instead, they make webs to hide inside, which is how it got the name sac spider.
They’ve been known to bite humans, and the bite is quite painful because of their large fangs. Some people have bad reactions, but this is rare. Overall, they are not considered dangerous.
#21. Spined Micrathena
- Micrathena gracilis
Also known as the Spiny-Bellied Orbweaver, Spiny Orb Weaver, and Castleback Orbweaver.
- Females grow to 8-10 mm (0.31-0.39 in) in size. Males average 4.5 mm (0.18 in) long.
- They are white or yellowish with dark mottles.
- You might notice prominent black spines on their big abdomens.
The Spined Micrathena is an impressive spider to see in Iowa.
If you’re eager to find one, you’ll have the best luck searching in hardwood forests along ponds or lagoons. These day-dwelling creatures are most active during late summer and early fall.
The webs of this species are large, tightly coiled, and can reach 200 mm (8 in) across. As with most orb-weavers, they connect a long line of silk to a branch above their webs to use as an escape route.
Spined Micrathenas easily catch mosquitos, gnats, and small flying insects in their sticky webs. They are wanderers, spending only a week at one location before moving on to the next. If you encounter one, rest assured that its venom is too mild to harm you.
#22. Northern Yellow Sac Spider
- Cheiracanthium mildei
- The body is typically tan or pale green. The mouthparts are darker brown.
- Adults are typically 7–10 mm (0.3–0.4 in) in size.
Northern Yellow Sac Spiders are NOT NATIVE to Iowa.
They are originally from Europe and North Africa and were introduced long ago by English colonists. But since they have been here so long, these spiders are now common, especially INSIDE homes.
Unfortunately, Northern Yellow Sac Spiders will bite a human without hesitation. In fact, they have been observed crawling across the skin and biting for no particular reason. Luckily, bites from this species are relatively painless and medically insignificant. But bites from its cousin, the Yellow Sac Spider (Cheiracanthium inclusum), are MUCH more serious.
#23. Brown Recluse
- Loxosceles reclusa
Also known as the Violin Spider or Fiddle Back.
- Both sexes are around 7 mm long.
- Yellowish to grayish brown. The head is often darker, usually with faint or distinct violin-shaped marks.
- Long legs.
These venomous spiders are found in Iowa both outdoors AND indoors.
Yes, you can’t even escape them in your house, as Brown Recluses commonly live in homes and buildings. They prefer dimly lit locations, like dark corners in a basement, closets, cluttered areas, or even inside your shoe or bed!
Brown Recluse Range Map
Luckily, Brown Recluse bites are rare and only bite if provoked.
Unfortunately, since they live indoors, bites often occur when you accidentally step or roll on them while sleeping. The bite is painless, so you may not even know you’ve been bitten until later.
Watch this video to see the damage a Brown Recluse bite can cause!
Bites can result in lesions, nausea, fever, and wounds that are slow to heal, becoming necrotic and sometimes causing secondary infections. Necrosis (death of cells) sets in quickly, resulting in a painful and gruesome “flesh-rotting” wound.
Learn more about animals found in Iowa!
23 Common SNAKES That Live in Iowa! (ID Guide)
33 Common Bird Species Found in Iowa! (With Photos)
Do you need more help identifying a spider you found in Iowa?
Try this field guide!
Which of these spiders have you seen in Iowa?
Leave a comment below!