Spiders are some of the hardest working wildlife in Maryland. Many people are fearful of spiders and often overlook the critical role they play controlling insect pests. Knowing how to distinguish some of the different types of spiders and understanding the important functions that they serve in our environment can often lead to a greater appreciation of their beneficial qualities. This online guide is not an inclusive list of spiders found in Maryland, but it contains many commonly encountered spiders. There are over 40,700 species of spiders worldwide and hundreds of species in Maryland.
Maryland is home to a fascinating diversity of spider species. While most people are creeped out by spiders, these eight-legged creatures play an important role in our ecosystems. Spiders help control insect populations and are an integral part of natural food chains.
In this article, we’ll explore some of the most common spiders found in Maryland, how to identify them, and interesting facts about their behavior and habitats.
Overview of Spider Biodiversity in Maryland
There are over 650 species of spiders living in Maryland. This includes orb weavers, jumping spiders, crab spiders, wolf spiders, nursery web spiders, and web-building spiders.
Some of the most frequently encountered spiders in the state include
- Garden spiders
- Jumping spiders
- Crab spiders
- Wolf spiders
- Orbweavers
- Cobweb spiders
- Recluse spiders (rare)
- Widow spiders
While the majority of Maryland spiders are harmless to humans there are a few venomous species to watch out for, like the northern black widow and the brown recluse spider. Bites from these spiders can be medically significant so it’s useful to know how to identify them.
Common Maryland Spiders and How to Identify Them
Here is an overview of some of the most common spiders found in Maryland, along with tips on how to identify them:
1. Black and Yellow Garden Spider
The black and yellow garden spider (Argiope aurantia) is one of the most familiar orb weavers in Maryland. The adult female has a round, bulbous abdomen with black, yellow, and silvery markings. Her legs are banded with black, yellow, and orange.
These spiders build large, circular webs in fields, forests, and gardens. Their webs can measure up to 2 feet across. The spider hangs upside down in the center of the web and waits for prey like insects and even small birds to become ensnared.
2. Jumping Spiders
More than 300 jumping spider species call Maryland home. Some common ones include the daring jumping spider (Phidippus audax) and the bronze jumping spider (Eris militaris).
Jumping spiders are compact, hairy spiders that actively hunt their prey. As their name suggests, they can jump several times their body length to ambush insect prey or evade predators.
Some identifying features are their short front legs, rectangular-shaped bodies, and eight eyes, with two large predominant eyes in the front. Jumping spiders come in various colors like black, brown, white, and metallic greens.
3. Crab Spiders
Crab spiders have a crab-like appearance, with their legs projecting out sideways from their bodies. They come in various colors like white, yellow, and red. These ambush predators sit camouflaged on flowers and foliage waiting for pollinators like bees to come within striking range.
Some crab spiders even have the ability to change their body color to match their surroundings. For example, the white crab spider turns yellow when sitting on yellow flowers.
4. Wolf Spiders
Wolf spiders are hairy, brown spiders that actively hunt down their prey. They have excellent vision and don’t build webs to trap insects. Some wolf spiders found in Maryland include the rabid wolf spider (Rabidosa rabida) and the Carolina wolf spider (Hogna carolinensis).
Wolf spiders have a unique eye pattern – four small eyes in the front row and four larger eyes behind. Females carry their egg sacs attached to their spinnerets. The spiderlings climb on their mother’s back after hatching.
5. Orb Weavers
Orb weaver spiders construct circular, wheel-shaped webs using sticky silk to trap their prey. Some common orb weavers in Maryland are the marbled orb weaver (Araneus marmoreus), banded garden spider (Argiope trifasciata), barn spider (Araneus cavaticus), and arrowhead orbweaver (Verrucosa arenata).
Orb weavers have rounded, bulb-shaped abdomens. The color and patterns of their bodies help camouflage them in their webs. For example, the arrowhead orbweaver has a distinct arrowhead-shaped marking on its abdomen.
6. Cobweb Spiders
Cobweb spiders (Theridiidae family) are small spiders that build messy, tangled webs in undisturbed corners of homes. The tangle-web spider (Hahnia cinerea) and southern house spider (Kukulcania hibernalis) are two common cobweb weavers.
The cobweb spider’s web becomes covered in dust, making it more visible. The spider waits in its web to ambush prey like flies, mosquitoes, and other insects. Cobweb spider bites are generally harmless to humans.
7. Brown Recluse Spider
The venomous brown recluse spider (Loxosceles reclusa) is occasionally found in Maryland, though it is not native here. It likely hitchhikes into the state in shipping crates and moving boxes.
This light brown spider has a dark violin-shaped marking on its cephalothorax (head region). Their legs span approximately the size of a quarter coin. Brown recluse spiders build irregular webs in dark, undisturbed places like attics and crawl spaces.
Bites can cause necrosis of the surrounding skin. Seek medical attention if you suspect a brown recluse bite.
8. Northern Black Widow Spider
The northern black widow spider (Latrodectus variolus) is Maryland’s most venomous spider. Adult females have a shiny black body with a reddish hourglass marking on the underside of their bulbous abdomens.
Black widows build messy webs in secluded areas like basements, garages, hollow stumps, and wood piles. Their bite can be medically significant, so exercise caution when working around these areas. Antivenom is available to treat black widow bites.
Spider Habitats in Maryland
Maryland’s diverse landscape provides an abundance of habitats for spiders to thrive. Here are some of the common places you can find spiders around the state:
-
Woodlands: Orb weavers, crab spiders, and jumping spiders are found in Maryland’s deciduous forests. Cobweb spiders build webs in hollow logs.
-
Wetlands: Wolf spiders, fishing spiders, and marsh spiders inhabit marshes and swamps. Nursery web spiders live near the water’s edge.
-
Grasslands: Crab spiders, wolf spiders, and funnel weavers are found hunting in Maryland’s open fields and meadows.
-
Gardens: Orb weavers, crab spiders, and jumping spiders are common visitors to backyard gardens in Maryland.
-
Homes: House spiders like cobweb spiders and cellar spiders set up webs in dark corners of basements and attics. Jumping spiders also patrol indoors for insect prey.
Fun Facts About Maryland Spiders
Beyond being an essential part of our ecosystem, spiders are amazing creatures with some fascinating traits. Here are some interesting facts about Maryland spiders:
-
Wolf spiders carry their young on their backs until the spiderlings are ready to strike out on their own. Up to 100 babies can fit on an adult female’s abdomen!
-
The marbled orb weaver (Araneus marmoreus) destroys its web each morning and builds a completely new one every night.
-
Jumping spiders have excellent vision and can see color. They have four pairs of eyes, with the front pair having telephoto-like lenses.
-
Crab spiders change color over several days to match their background and camouflage themselves while hunting.
-
Baby grass spiders feed on their mother’s eggsac fluid for nourishment, and sometimes even feed on unhatched eggs.
-
Male black widow spiders risk their lives to mate. They approach females cautiously and often get eaten before they can reproduce!
Spider Bites in Maryland – Are They Dangerous?
The vast majority of spiders in Maryland are not dangerous to humans. Most spider bites cause only mild pain, redness, and itching that goes away within a few hours.
There are two spiders of medical concern – the northern black widow and the brown recluse spider. But spider bites from these species are extremely rare in Maryland.
Seeking prompt medical treatment is recommended if bitten by one of these venomous spiders to receive antivenom. Using common sense, protective clothing, and proper precautions can help avoid accidental bites when cleaning garages and basements where venomous spiders may lurk.
So while spiders may creep some people out, these fascinating creatures are an important part of Maryland’s biodiversity. Getting to know the most common species in your area and their habits can help you co-exist safely with these amazing arachnids.
Black and yellow garden spider (Argiope aurantia)
True to its name, the black and yellow garden spider is often seen n and around gardens. These spiders are orb-weavers, meaning that they spin their webs in a circle or an orb. These webs can be up to 2 feet across, while the spiders themselves can have a leg span of nearly 2.5 inches! Females are much larger than the males, and often times, these spiders will decorate their web with a zig-zag of white silk. Black and yellow garden spiders prefer to build their webs in sunny areas and often will rebuild their webs every day.
Spiders in the genus Micrathena tend to have spiky abdomens and are notorious for weaving webs at face level along trails. If you have ever run into a spider’s web in late summer while hiking in Maryland, then there is a good chance it was a Micrathena web! Micrathena spiders feed mostly on small flies, gnats and mosquitoes. Males do not build webs, rather they let the ladies do all the work. When a male is ready to mate, he will weave a ‘mating thread’ into her web before mating with her. Many times, females will kill the males shortly after mating. Spined Micrathena spiders (Micrathena gracilis) are the most common Micrathena in Maryland.
Cobweb spiders amily: Theridiidae
Black widows are distinctive spiders. The females are shiny black with a red hourglass on the bottom of her abdomen while males have a more vibrant pattern on their abdomen consisting of many red and white spots. Male black widow spiders are rarely encountered and are not known to bite humans.
Black widow bites feel like a minor pinprick, but dull pains will soon develop in the area of the bite. The affected area will generally begin to cramp and other symptoms such as sweating, nausea and vomiting may occur.
Black widow spiders are cobweb spiders that spend most of their time in their webs. Black widows tend to make their webs in undisturbed, uncluttered areas on porches and in sheds. To discourage them from inhabiting an area, then knock down their webs with a broom or a high pressure hose. In some areas, you can vacuum up spiders and their eggs, but be sure to immediately place the vacuum cleaner bag in a plastic bag, seal tightly, and discard in a container outdoors as this prevents captured spiders from escaping into the home.
20 Spiders Every Marylander Should Know!
FAQ
Are there any poisonous spiders in Maryland?
Many of the spiders in Maryland possess venom, but the black widow is the only native Maryland spider that is dangerous to people. All other venomous Maryland spiders either have too little venom to affect people or their venom is specially adapted for their prey.
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.
What are the big yellow and black spiders in Maryland?
More than 250 species of spiders can be found in Maryland and one of the largest and more visible species is the black and yellow garden spider (Argiope aurantia). Also affectionately known as the writing spider, the black and yellow garden spider fashions an intricate zig-zag pattern in the center of its web.