24 Spider Species Found in Iowa (With Pictures)

Love them, hate them, or fear them, spiders are impossible to avoid. In Iowa, spiders are found everywhere from cornfields to forests to the basements where we retreat when the tornado sirens go off. Arachnophobia is no joke but the reality is only two poisonous spider species are found in Iowa and their bites are rarely fatal. Here are 24 spiders found in Iowa and a little information about each one!

The 24 Spiders Found in Iowa

1. Black Widow

One of two poisonous spiders in Iowa, black widows are found in dark, dry locations,  indoors and out. The females are larger and black, with a red hourglass marking on their abdomens. Males are smaller and lighter in color, with red or pink spots. The black widowʻs bite is painful but rarely fatal to humans.

2. Brown Recluse

The other poisonous spider species in Iowa is the Brown Recluse. These spiders are small, brown in color, with a dark violin-shaped marking on their bodies. Brown recluse spiders are shy and non-aggressive, preferring to spin their webs in warm, dark locations like basements, sheds, or woodpiles. Their bite is painful but rarely fatal to humans, although dogs and cats can suffer more serious impacts.

3. Carolina Wolf Spider

The largest spider in Iowa is the Carolina Wolf Spider, a hairy brown and black spider that hunts their prey rather than spinning webs. Wolf spiders live in any habitat from forests to fields and occasionally wander into houses. They eat invertebrates and sometimes small amphibians and reptiles. Birds, snakes, frogs are common predators for wolf spiders. Several wasp species use wolf spiders to incubate their young, injecting their eggs into the paralyzed spider. The wasp larvae then eat the spider from the inside out after hatching.

4. Common House Spider

Common house spiders live where humans do, spinning their webs in any quiet corner they can find. Donʻt rush to evict them if you do find one, however, as house spiders are wonderful natural pest control. Theyʻll make a meal out of most annoying household insects, including flies and mosquitoes. These spiders are small and usually a mix of brown, black and white coloring.

5. Dark Fishing Spider

Another large Iowa spider is the Dark fishing spider, usually found outdoors near a water source. They can dive into and move across the surface of the water to hunt their prey, including aquatic insects. Dark fishing spiders are brown, gray, and black with excellent vision for hunting prey.

6. Woodlouse Hunter Spider

Woodlouse hunter spiders are small reddish spiders who feed exclusively on woodlice. They live outdoors, usually near logs, and hunt at night. Though not poisonous, their bite is painful and sometimes causes allergic reactions in humans.

7. Grass Spider

Grass spiders build large webs with a tunnel on one side to capture their insect prey. They live outdoors in grass, weeds, or other plants. Grass spiders are yellow-brown with two dark lines extending back from their eyes.

8. Yellow Sac Spider

Yellow sac spiders are nocturnal hunting spiders, found both outdoors and inside houses. They are small, yellowish spiders who prey on insects and other spiders. While not poisonous, yellow sac spiders are responsible for most human spider bites because their night hunting often brings them into contact with sleeping people.

9. Black and Yellow Garden Spider

Black and yellow garden spiders make their home outdoors, usually in yards or near houses. They build intricate webs up to 2 feet in size to catch insects and smaller spiders. These spiders have long legs and colorful black and yellow abdomens.

10. Barn Funnel Weaver Spider

Mostly found in sheds, barns, or houses, the barn funnel weaver is a small, shy web-building spider. They are a range of colors from dark orange to brown to gray, with striped legs. Barn funnel weavers eat insects while dodging their natural predators, birds, and reptiles.

11. Cellar Spider

Commonly found in dark corners of buildings, cellar spiders have small bodies and extra-long legs. They are slow-moving spiders who build webs to capture insects for food. If insects run low, these spiders find the webs of other spiders, shake them to imitate captured prey, and make a meal of the unsuspecting spider who comes looking.

12. Shamrock Orb Weaver

Shamrock orb-weavers weave a new, round web every morning to capture and eat flying insects. These spiders can be brown, greenish, orange, or yellow with white dots on their back. They are commonly found in yards, grasslands, and forests.

13. Spotted Orb Weaver

Spotted orb-weavers are nocturnal, found in yards, forests, and other outdoor locations. They are hairy spiders, found in tan, yellow-brown, or orange coloring, with dark zigzag patterns on their abdomen. They primarily eat moths and their egg sacs are often eaten by birds in winter when other food is scarce.

14. Orchard Spider

These colorful spiders often spin their webs in small trees. They have green legs and heads, with round silver or white abdomens. They have spots and markings in colors like green, yellow, black, orange, or pink. Orchard spiders feed on flying insects such as flies and leafcutters.

15. Eastern Parson Spider

Eastern Parson spiders are hairy black or brown spiders with a white marking on their backs that looks like a clerical collar. They live in the woods but may make their way into houses. Parson spiders are nocturnal hunters with painful bites known to cause allergic reactions in people.

16. Marbled Orb Weaver

Marbled orb-weavers are also called pumpkin spiders because of their large round orange-yellow abdomens with dark markings. They are found in wooded areas, often near streams where they build large webs to snare flying insects.

17. Bridge Orb Weaver

These spiders are also called gray cross spiders for the distinctive pattern found on their brownish-gray abdomens. They build their webs near buildings or bridges, by artificial light sources and water. Bridge orb-weavers are nocturnal and prey on flying aquatic insects.

18. Bold Jumping Spider

Bold jumping spiders are small, fuzzy spiders with amazing vision and the ability to jump long distances. They are black or brown with white spots on the abdomen. Found in open areas, these spiders hunt insects and caterpillars. When jumping or exploring, they often spin a silk “safety rope” to anchor themselves.

19. White Micrathena

White micrathena are small, web-building spiders found in forests or in yards near homes. Their abdomens are white with black markings and 4 distinctive spines. They build webs close to the ground and feed on small flying insects like mosquitos.

20. Triangulate Cobweb

These small spiders are found (if you see them at all!) spinning webs in dark corners of houses, basements, or sheds. They are brown-orange, with yellow legs and white and yellow triangular markings. Triangulate cobweb spiders prey on small invertebrates like ants and ticks.

21. Banded Garden Spider

Banded garden spiders are typically silver in color, with dark bands on the abdomen and yellow-brown legs. They eat insects like grasshoppers and are themselves eaten by larger spiders, birds, and lizards.

22. Six-Spotted Fishing Spider

Six-spotted fishing spiders are large, speedy hunting spiders who live in wetlands and near bodies of water. They can run across the water surface, dive below it and even encase their bodies in an air bubble to stay underwater for several minutes. They eat aquatic insects and tadpoles.

23. Furrow Orb Weaver

Furrow orb-weavers can be tan, brown, gray, reddish, or olive-colored but they all have a single dark, zigzag mark down their shiny abdomen. These spiders prefer humid, low-lying habitats. They build webs near light sources that attract nocturnal flying insects for food.

24. Tuft-legged Orb Weaver

Tuft-legged orb-weavers are brown and black with long, spiky leg hair. They are found in woods, fields, or yards, where they build tightly meshed webs to catch all sizes of insects.

Conclusion

Spiders play a vital role in the health of our Iowa ecosystems, not to mention help keep our summer nights free of pesky mosquitos! These 24 spiders are large and small, web-spinners and ground hunters. No matter how you feel about spiders, the benefits of having them around are impossible to deny.

Related Read: 

• 12 Spiders Found in Virginia
• 5 Spiders Found in Oregon

Featured Image Credit: Liz Weber, Shutterstock