Missouri is home to a fascinating diversity of spider species These eight-legged creatures can be found in backyards, fields, forests, and even inside homes across the state While some spiders get a bad rap, most are harmless or even beneficial to humans.
This article will provide an overview of some of the most notable spiders found in Missouri, including how to identify them, where they live, what they eat, and whether they pose any danger
Why Spiders Matter
Spiders play a vital ecological role as predators of insects, helping to control pest populations A 2017 study estimated that the global spider community consumes 400-800 million tons of prey annually, mostly insects. Without spiders acting as natural pest control, insects would reach much higher numbers
Spiders also help indicate environmental health. The presence and diversity of spiders can reflect the abundance of prey species and quality of habitat in an area.
Spider Anatomy
All spiders have eight walking legs, usually with tiny claws at the tips. Most have six to eight eyes on top of their head, providing excellent vision including depth perception.
While many build webs to catch prey, others actively hunt instead. Spiders immobilize victims using venom injected through their fangs, then liquefy the internal organs to ingest the “bug smoothie.”
Only two spiders in Missouri have venom considered medically significant to humans – the black widow and brown recluse. Most have harmless venom used only to subdue small prey.
Common Garden and Orb Weavers
Several orb weaver spider species spin beautiful circular webs in gardens across Missouri.
The distinctive yellow garden spider has a zig-zag pattern. The boldly spotted marbled orb weaver comes in variable colors.
The aptly named arrowhead orb weaver has a triangular spear-shaped abdomen. The smaller furrow orbweaver likes moist areas.
These docile spiders are unlikely to bite humans unless severely provoked. Their venom only causes temporary redness and itching if they do bite in self-defense.
Ambush Predators
Jumping spiders and wolf spiders forgo webs to actively hunt prey on foot. Jumping spiders can leap up to 50 times their body length to ambush victims! Hairy wolf spiders prowl the ground for bugs.
The Missouri tarantula is a docile species found in Ozark burrows. Despite their fearsome appearance, wolf spiders and tarantulas bite only when threatened. Effects are similar to a bee sting.
Cellar Spiders and Harvestmen
Long-legged cellar spiders build messy-looking webs in dark corners of basements and sheds to snare prey.
Harvestmen are not actually spiders at all – they have just one body segment instead of two. These harmless scavengers are the “daddy longlegs” seen in Missouri fields.
Venomous Species
The shy brown recluse has a violin-shaped marking on its head. Its hemotoxic venom can cause necrosis in extreme cases. But 90% of bites heal naturally without issue.
Red hourglass markings help identify female black widows. This neurotoxic venom is rarely fatal, despite reputation. Painful bites may require medical treatment.
Both spiders bite only when pressed directly against skin and should not be feared – just respected. Proper precautions easily prevent encounters.
Crab Spiders and Lynx Spiders
Crab spiders ambush prey from flowers, able to change color to camouflage with petals. The striped lynx spider actively prowls for ground bugs during daytime. Neither variety spins webs to trap victims.
Beneficial Predators
Many common spiders prey on pesky insects, serving as free natural pest control. The spined banded orb weaver consumes crop pests.
Jumping spiders eat flies, mosquitoes, and other household bugs. Even the creepy looking cellar spider helps by catching disease-carrying mosquitoes.
Overall, spiders in Missouri should be appreciated for their ecological services, admired for their unique traits, and given their space. Understanding their benefits and how to identify any dangerous species allows us to coexist with these fascinating creatures.
Title Spider Versus Spider Body
The worst enemies of spiders usually are other spiders, but some insects, like the assassin bug and mud dauber wasp, prey upon them, as do bats, shrews and birds. Some orb weaving spiders construct a zigzag pattern of silk, the stabilimentum, at the hub of their webs which, scientists hypothesize, may deter birds from flying into the silk structure. But it might also help birds locate an orb weaver in order to prey upon it.
Title How They Grow Body
Spiders grow by molting, or ecdysis. In this process, the spider casts off its tight outer body cover—its exoskeleton—after secreting a new, larger one underneath. Spiderlings gradually develop into adults in this way. Some have peculiar color patterns that change as they approach adulthood. Few spiders molt after sexual maturity, but some, such as female tarantulas, do.
All spiders exhibit similar premolting behavior. They do not eat, become lethargic and retreat into silken molting quarters in a burrow, under a leaf or in a corner. The outer skeleton splits along the upper body portions and the spider gradually slips its body and legs from the old casing, much like taking off a skin-tight glove. The actual molting process varies among species and can take from less than 15 minutes to a full day. Molting spiders are particularly vulnerable; they are unable to move away or fight back because they must rest until their new exoskeletons harden.
Spiders in the Home (University of Missouri)
FAQ
What is the most common spider in Missouri?
Micrathena gracilis (spined micrathena, spiny-bellied orbweaver) There are three different species of micrathena spider found in Missouri. Of these, Micrathena gracilis is the most common, especially in the central and southern parts of the state. These spiders make orb webs between trees and bushes.
Are there poisonous spiders in Missouri?
Of the two potentially harmful spiders found in Missouri, you are more likely to encounter the brown recluse than the black widow. Both can inflict bites that can cause severe pain and infection.
What is the biggest spider in Missouri?
The Texas brown tarantula is a stocky, hairy species and is Missouri’s largest spider. The body and legs are uniformly dark chocolate brown, with reddish hairs on the carapace.
How do I identify a spider I found?
Look at the size of the legs in proportion to the body. Some spiders have long, thin legs (like the yellow sac), while others have stocky, thick legs (like the wolf spider). Some spiders (such as the lynx spider) have tiny hairs on their legs, while others have spikes (such as the funnel spider) or fur.
Are there spiders in Missouri?
Only two species of spider in Missouri are considered medically significant: the brown recluse and female “black widow.” True spiders are members of the order Araneae. They have 8 walking legs with tiny retractable claws on each foot. Most have a cluster of 6-8 eyes on the top of their head.
What do spiders look like in Missouri?
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 Missouri in late summer and early fall. Look for their large, orb-shaped web near lights, often constructed on buildings or other man-made objects.
What do house spiders eat in Missouri?
House spiders usually eat insects but can also survive on a diet of dust and cobwebs. In Missouri, common house spiders can be found in both rural and urban areas. These spiders are not particular about where they build their webs and can often be seen in basements, attics, and closets.
Are black widow spiders medically significant in Missouri?
Usually, this only results in temporary redness and itching. Only two species of spider in Missouri are considered medically significant: the brown recluse and female “black widow.” True spiders are members of the order Araneae. They have 8 walking legs with tiny retractable claws on each foot.
What color are crab spiders in Missouri?
Identifying Characteristics: 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 Missouri are near flowers. Crab spiders don’t use webs to catch their prey.
What are the most venomous spiders in Missouri?
Black Widows are the most venomous spiders in Missouri! 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.