Types of Trapdoor Spiders: Discovering Nature’s Hidden World

Trapdoor spiders are fascinating creatures that belong to the Araneae order and the Ctenizidae family. One of the most speciose genera within this family is Ummidia, which includes around 50 species, some of which are still undescribed. These spiders can be found all across the United States, particularly in the East and the Southwest, extending up to Colorado. They’re known for their interesting habits and unique physical features, such as their silk-lined, underground burrows with trapdoor-like lids for camouflage and ambush.

As you explore the world of trapdoor spiders, you’ll discover that they have a few natural enemies. One notable predator is the spider wasps from the Pompilidae family. These wasps are known to specialize in hunting and parasitizing spiders, including tarantula hawks, which are large pompilid wasps that commonly attack tarantulas. It’s essential to understand how these various types of trapdoor spiders interact with their environment and other species, in order to appreciate their role in the ecosystem better.

Additionally, the diverse habitats within which trapdoor spiders thrive include shaded ravines, north-facing slopes, and specific soil types. Recognizing these microhabitat preferences is crucial as it highlights the importance of preserving these habitats to support the ongoing survival and conservation of trapdoor spiders. So, as you delve into the intriguing world of these spiders, you’ll uncover the captivating features and ecological significance of trapdoor spiders in our vast and complex natural world.

Overview of Trapdoor Spiders

Trapdoor spiders are fascinating creatures belonging to the infraorder Mygalomorphae. These spiders are known for their unique hunting techniques and intriguing burrows.

These spiders inhabit silk-lined, underground burrows with their namesake “trapdoors.” As they wait for prey, they remain hidden within their burrows and quickly emerge to catch unsuspecting victims. Trapdoor spiders are widespread in locations such as the United States and Australia.

One key feature of trapdoor spiders is their poor dispersal capabilities. Unlike some species like the Ummidia Thorell, these spiders rarely disperse by ballooning.

A couple of interesting characteristics to note about trapdoor spiders are:

• They are generally large and stout-bodied
• They have vertically moving jaws
• They are long-lived, with some species living up to 25 years

Various species of trapdoor spiders exist, such as the Ummidia, which is the most speciose genus with about 50 different species. Other species belonging to the Conothele Thorell line are known as “cork-lid trapdoor spiders.” Elements such as size, leg span, and behavior may differ slightly between species.

In conclusion, trapdoor spiders are an intriguing group of mygalomorph spiders. With their distinct hunting techniques, various species, and notable characteristics, they offer a fascinating subject for all who encounter them.

Physical Characteristics

General Appearance

Trapdoor spiders typically have a dark, black color that helps them blend into their surroundings. The abdomen is covered in thick, coarse hairs which provide them with some protection and insulation. Some notable features of these spiders include:

• Large, powerful jaws
• Stout, sturdy legs
• Stocky, almost armored body

Male Vs. Female Trapdoor Spiders

When comparing males and females, there are some differences in their physical appearance:

Male Trapdoor Spiders:

• Smaller in size compared to females
• More slender abdomen
• Longer, more agile legs for wandering during mating season

Female Trapdoor Spiders:

• Larger and more robust than males
• Abdomen is wider and rounder, suited for carrying eggs
• Less mobile, spending most of their lives within their burrows

A comparison table between male and female trapdoor spiders can be helpful:

Brush-Footed Trapdoor Spiders

A unique group within the trapdoor spider family are the brush-footed trapdoor spiders. Some distinguishing characteristics include:

• Soft, brush-like hairs on their front legs
• Use their modified front legs for sensing vibrations in their environment
• Often found in very specific habitats, such as coastal sand dunes or woodland areas

To summarize, trapdoor spiders are fascinating creatures with unique physical characteristics that set them apart from other species. By understanding their general appearance, differences between males and females, and the intriguing brush-footed trapdoor spiders, you can better appreciate the complexity of these amazing arthropods.

Habitat and Distribution

North America

In North America, trapdoor spiders of the genus Ummidia can be found. They live in silk-lined, underground burrows across the eastern US and the southwest, spanning as far north as Colorado. Ummidia is a diverse genus, with about 50 species, including several undiscovered ones.

South America

South American trapdoor spiders belong to the New World Ummidia species. With 20 known species present in this region, South America has a rich diversity of trapdoor spiders.

Australia

In Australia, you can find trapdoor spiders from the family Halonoproctidae. One example is the Conothele Thorell species, which belongs to this family and has poor dispersal capabilities.

Japan

Trapdoor spiders are less common in Japan, and information about specific species in this region is limited. However, it’s possible that some species from the Mygalomorphae suborder, which includes trapdoor spiders, inhabit Japan.

Singapore

Similar to Japan, specific details about trapdoor spiders in Singapore are limited. But, since Singapore is rich in biodiversity, it’s reasonable to expect some species of trapdoor spiders to reside there.

Papua New Guinea

Papua New Guinea houses many species of trapdoor spiders, primarily from the Conothele Thorell genus. These spiders, also in the Halonoproctidae family, may have speciation patterns influenced by their habitats and distribution patterns.

In conclusion, trapdoor spiders can be found across various continents, inhabiting diverse habitats. They typically live in silk-lined, underground burrows and are distributed across regions like North and South America, Australia, and Papua New Guinea. While specific information about species in Japan and Singapore is limited, it’s likely that these countries also house some types of trapdoor spiders.

Classification and Families

Ctenizidae

Ctenizidae is a family of trapdoor spiders known for their silk-lined, underground burrows. The most speciose genus within this family is Ummidia, with about 50 species, several of which are undescribed¹. Some examples of Ctenizidae include:

• Ummidia sp.
• Conothele Thorell

Idiopidae

Idiopidae are another family within the Mygalomorphae infraorder. They are also referred to as “armored trapdoor spiders.” Similar to other trapdoor spiders, they too live in silk-lined burrows.

Actinopodidae

Actinopodidae is a family of spiders that mainly reside in South America and Australia. They are known as “mouse spiders” or “funnel-web tarantulas.” They differ from other trapdoor spiders due to the distinction in their burrow and web structure.

Barychelidae

Barychelidae, also known as “brush-footed trapdoor spiders,” are predominantly found in tropical regions. These spiders have thick, brush-like scopulae on their limbs, hence their common name.

Cyrtaucheniidae

Cyrtaucheniidae are referred to as “wafer-lid trapdoor spiders” because of their unique lid structure. Their distribution is mainly across the Americas and Africa.

Migidae

Migidae, often called “tree trapdoor spiders,” prefer arboreal (tree-dwelling) habitats. They are mainly found in Australia, Africa, and South America.

Antrodiaetidae

Antrodiaetidae, or “folding-door spiders,” are native to North America. These spiders create burrows that have unique lids resembling folding doors.

Halonoproctidae

The Halonoproctidae family is an updated classification that now includes some spiders previously under the Ctenizidae family². Examples of Halonoproctidae are the Conothele Thorell and Ummidia sp.

Nemesiidae

Nemesiidae is a widespread family of trapdoor spiders present in various habitats. They are commonly found in temperate to subtropical regions.

Theraphosidae

The Theraphosidae family comprises well-known spiders such as tarantulas. They are primarily known for their size and robust, hairy bodies.

Behavior and Lifestyle

Diet and Prey

Trapdoor spiders primarily feed on insects such as flies, moths, and caterpillars. They also consume other arthropods like centipedes and even smaller spiders. You might find it interesting that some larger species can prey on small vertebrates like frogs and mice.

These spiders are ambush predators. They wait in their silk-lined, underground burrows until they detect vibrations from a passing prey. Once the suitable prey crosses their path, they quickly emerge to capture it.

Predators

Trapdoor spiders, despite their impressive hunting skills, have their own set of natural predators. Some of these predators include:

• Birds: Birds such as magpies can locate and dig out trapdoor spiders from their burrows.
• Wasps: Certain parasitic wasps specifically target trapdoor spiders, laying their eggs on or inside the spider, which eventually leads to the spider’s demise.
• Scorpions: These arachnids share similar habitats with trapdoor spiders and can prey on them given the opportunity.
• Bandicoots: Small, insectivorous mammals like bandicoots may dig up trapdoor spiders as they forage for food.

Although trapdoor spiders are generally timid and prefer to stay hidden, their lives may still often be in danger from these predators. To protect themselves, they rely on their burrow’s secure doors and their ability to sense vibrations, staying out of sight whenever possible.

Reproduction and Spiderlings

Trapdoor spiders, like the ones from the genus Ummidia, reproduce through mating. In this process, a mature male spider encounters a female and mates with her. Mating can be a risky venture for the male as some females may try to eat them after mating.

After a successful mating, the female lays her eggs. These eggs mature within her silk-lined burrow, where they remain protected. Once the eggs hatch, they produce a brood of spiderlings.

• Spiderlings are small versions of adult trapdoor spiders.
• They remain with their mother for a short period.

As they grow, spiderlings gradually venture out of their mother’s burrow. They create their own silk-lined burrows and start hunting for prey. With each molt, the spiderlings get closer to their adult size.

Remember:

• Mature males leave their burrows to find mates.
• Females lay eggs in their burrows and care for the spiderlings.

In summary, trapdoor spider reproduction involves a mature male seeking a female for mating. After mating, a female lays eggs in her burrow, which eventually hatch into spiderlings. These spiderlings stay close to their mother until they’re capable of venturing out and building their own burrows, signaling the start of their independent lives.

Human Interaction and Bites

Trapdoor spiders are generally not known to cause harm to humans. They prefer hiding in their burrows, avoiding contact with people. However, if they feel threatened or accidentally disturbed, these spiders might bite in self-defense.

The pain caused by a trapdoor spider bite can vary. Some bites might be slightly painful, while others can be more severe. It’s essential to know that different species might have different effects on people due to their venom. For example, bites from the following spiders can result in serious consequences:

• Species 1
• Species 2
• Species 3

In general, it is wise to take precautionary measures when working or walking near areas where trapdoor spiders might reside. Keeping your distance and being mindful of your surroundings can help reduce the likelihood of encountering a trapdoor spider and minimize the risk of being bitten.

Here is a comparison table to summarize some general factors regarding trapdoor spider bites:

By respecting these spiders’ habitats and taking necessary precautions, you can reduce the possibility of an unpleasant encounter with a trapdoor spider and enjoy the outdoors without worry.

Trapdoor Spiders and Arachnologists

Trapdoor spiders are fascinating arachnids studied by arachnologists. These unique creatures live in silk-lined, underground burrows and are known for their stealthy hunting techniques. One trapdoor spider genus that arachnologists often study is Ummidia, which is widespread in the United States and has about 50 species.

As an enthusiast of arachnids, you might be surprised by the amount of new species continuously being discovered. For example, only five species were described in the past 125 years in the Myrmekiaphila genus, yet researchers believe there could be even more undiscovered ones. This highlights the vastness of these elusive creatures waiting to be explored by arachnologists.

Some unique features of trapdoor spiders include:

• Silk-lined burrows for habitat
• Hinged, camouflaged “trap” made from silk and soil
• Ambush predators, capturing prey near the burrow entrance
• Limited long-distance dispersal ability

One interesting aspect of trapdoor spiders is their limited vagility when compared to other arachnids or even some vertebrates. Arachnologists have found that trapdoor spiders have extreme population structuring and are known to be non-vagile, meaning they usually don’t move long distances.

In conclusion, trapdoor spiders showcase the diverse world of arachnids, offering arachnologists a broad variety of species across multiple genera to study and understand. As you delve into arachnids, keep in mind the fascinating features and behaviors these creatures have to offer, making them an exciting subject to learn more about.

Role in Ecosystems

Trapdoor spiders play an essential role in their ecosystems. These arthropods are predators that help control insect populations, balancing the flora and fauna within their habitat.

As a hunter, the trapdoor spider lies in wait until an unsuspecting insect comes too close to its silk-lined, underground burrow. Once the prey is within reach, the spider quickly snatches the unfortunate insect and pulls it back into the burrow for consumption. This action helps keep insect populations in check.

Trapdoor spiders contribute to the complex web of interactions among various species in the ecosystem. They are an important source of food for other animals, such as birds, reptiles, and mammals. By serving as both predator and prey, trapdoor spiders play a role in maintaining the stability and diversity of the ecosystem.

Their burrowing behavior benefits the soil by aerating it and allowing water to penetrate deeper. This creates a healthier environment for plants and other organisms that live underground. Furthermore, trapdoor spiders’ activities contribute to controlling potentially harmful insects that can damage plants or transmit diseases to fauna.

In short, the presence of trapdoor spiders benefits their ecosystem by:

• Controlling insect populations
• Serving as a food source for larger predators
• Aiding in soil aeration and water penetration

By understanding the importance of trapdoor spiders in ecosystems, you can appreciate their role in maintaining balance among flora and fauna, showcasing the interconnectedness of all living organisms.

Historical and Archaeological Significance

Fossil Record

You may wonder about the historical and archaeological significance of trapdoor spiders. A major aspect is the existence of extinct species, preserved as spider fossils. Studying these fossils provides valuable insights into the evolution and ancient history of these fascinating creatures.

In particular, spider fossils from the Miocene era have been discovered and analyzed. The Zoological Journal of the Linnean Society has published findings on some of these ancient specimens, offering a better understanding of trapdoor spider species through time.

Specific Discoveries

One remarkable discovery took place in Australia, at a site called McGraths Flat. Researchers found what appears to be the first-ever fossil of an Australian trapdoor spider, which has been named Megamonodontium mccluskyi. This discovery is notable because it documents the presence of trapdoor spiders in Australia millions of years ago.

Another interesting deposit of spider fossils is the goethite formation, a type of iron oxide mineral that preserves spider remains exceptionally well. The analysis of these fossils contributes to our knowledge of extinct spider lineages, helping shed light on their morphology and behavior.

To summarize:

• Fossil records show the existence of extinct trapdoor spider species
• Miocene Era spider fossils have been studied extensively
• Specific discoveries include Megamonodontium mccluskyi and goethite-preserved specimens

By exploring the historical and archaeological significance of trapdoor spiders, researchers can better understand these creatures and their contribution to Earth’s biodiversity through time.

Reader Emails

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

Letter 1 – Trapdoor Spider

Spider?
Hi Bugman
I discovered this spider on the steps at work in Kill Devil Hills N.C. two days before Christmas at around midnight. I thought she was absolutely gorgeous so I took a couple pictures and returned her to the wild. I believe from your site that it is a female Trapdoor spider. I just love the blue abdomen. Can you confirm my supposition and any further information would be appreciated!

We agree that this is a Trapdoor Spider. It is in the genus Ummidia. We are not convinced it is a female. Females rarely leave their burrow and it is the males that wander in search of a mate. The legs on your specimen seem short (could be camera angle) like those of a female, but the pedipalps are rather large, indicating a male spider. Perhaps someone with more knowlege will write in to clarify.

Letter 2 – Trap Door Spider

HUGE Red Creepy Sow Bug Killer(?) in Oklahoma
April 20, 2010
Hi,
I found this nasty looking spider about a week ago in central Oklahoma. I think it’s a sow bug killer, but the coloring looks more red than the other pictures I’ve seen. He was about an inch and a half long. His eyes were grouped tightly together and his legs and abdomen were covered in black bristles. His pedipalps were really long, almost as long as his front legs, and I think he had “claws” on the ends (I couldn’t really tell because he kept them tucked up by his fangs). When I found him, he was hiding in a burrow under a log. This guy was really calm and cooperative as I took his picture. Thanks any help with the I.D.
Josh Kouri

Hi Josh,
This is definitely not a Sow Bug Killer, Dysdera crocata, which you can compare to this nice photograph of a similar angle on BugGuide.  Your spider looks to us like a Folding Door Spider in the genus Antrodiaetus which is also pictured on BugGuide.  Folding Door Spiders are a group of Trapdoor Spiders that live in tubes which they close by drawing in the rim according to BugGuide.

Thanks for the I.D. I never would have guessed he was a trap door spider. I didn’t even know we had them in Oklahoma!
Josh

Correction thanks to Eric Eaton
May 7, 2010
Daniel:
I agree the spider posted on April 21 is a type of trapdoor spider, just not in the family Antrodiaetidae.  More likely in the family Cyrtaucheniidae.  Positive, in fact.
Eric

Letter 3 – Newly Hatched Trapdoor Spiderlings

trapdoor spiderlings
i thought you might like to see the image of what i believe are trapdoor spiderlings recently emerged. found at skidaway island state park, ga
anthony

Hi Anthony,
Thanks so much for sending us your photo of alleged Trapdoor Spiderlings. We will agree with your identification until an expert writes in to correct us.

Letter 4 – Possibly Southwestern Trapdoor Spider

Subject:  Mygalomorphae
Geographic location of the bug:  South Texas
Date: 07/08/2021
Time: 02:05 PM EDT
Your letter to the bugman:  I found these two in a cup on my porch after returning from out of town after a few days. Someone told me they are mygalomorphae. My question is are they venomous/dangerous to man.
How you want your letter signed:  Dan

Dear Dan,
We suspect this might be a male Southwestern Trapdoor Spider, Eucteniza relata, which is pictured on BugGuide, or a closely related species and then again, we may be wrong.  Perhaps one of our readers more skilled in arachnology will be able to identify the species.  According to BugGuide:  “Eutecniza males can be recognized by the presence of 1-2 mid-ventral megaspines on the tibia of both legs I and II” but we do not have the necessary skills to make that definitive identification.  Your amusing collection of Trapdoor Spiders, Longhorned Borer Beetles and Cockroaches is quite the still life.  Trapdoor Spiders may bite humans but they are not considered dangerous.

Letter 5 – Rains bring out California Trapdoor Spiders in Northeast Los Angeles

Ed. Note:  These two submissions came to our personal email accounts from friends.  Of  California Trapdoor Spiders, Charles Hogue wrote in his landmark book Insects of the Los Angeles Basin in 1974:  “”Their rarity now is another example of human expansion destroying the habitat of a local animal.”  Luckily in Glassell Park and Mount Washington, we have a specific plan to help preserve open space and to limit development scale in the hillsides.  We are also blessed with many open space parks that serve as habitat preservation.

Trapdoor Spiders
Location:  Glassell Park, Los Angeles, California
November 1, 2014
Hi Daniel,
My tenant just found this beauty wondering around in the studio.  He looks enormous!  I’m guessing a good 2” long.
Any ideas of what he might be?
Helene

Hi Helene,
Tell your tenant that this is a male California Trapdoor Spider, and the first rains of the season generally trigger mating activity in the males which leave their burrows in search of a mate.  Clare send us an image of a male California Trapdoor Spider that she found on her front stoop yesterday.

Trapdoor Spider
November 1, 2013
Location:  Mount Washington, Los Angeles, California
he was huddled on the doorstep this morning.
so, i brought him in.
he’s cold. perhaps washed out of his burrow?
i think i should keep him for a few days until it dries up?
the, he could make a burrow more successfully.
would he eat small crickets?
he was frightened and on a slippery surface.
i moved him into an aerated jam jar which has soil in it.
so he’s happier.
i’ll let him go in a few days.
c.

Input from Julian Donahue
‘d release him (most likely male) now. Yes, rain probably brought him out, although this is the time of year males wander about looking for receptive females. That way you don’t have to worry about feeding him either–I suspect they don’t eat much, if at all, this time of year.
jpd

i transferred him to a pot with soil and lid.
will let hm go tomorrow.
i wonder if evening or daylight best?
the termites are swarming over here…
c.

I’d release him tonight–they seem to be primarily nocturnal, since that’s when they usually end up in the pool.
jpd

Letter 6 – Southern Coastal Dune Trapdoor Spider

Subject: brown spider!
Location: malibu, california
February 6, 2016 12:30 am
hi! we found this cool spider on the street between dunes/beach in malibu, california. tried googling and couldn’t figure out what it was
Signature: Thanks so much! Erica

Dear Erica,
We immediately recognized your spider as a Trapdoor Spider, but we are very excited as we believe we have correctly identified it as a Southern Coastal Dune Trapdoor Spider, Aptostichus simus, based on this BugGuide image.  All indications are that this species is endemic to coastal dunes in Southern California.  According to an online article we located:  “The tradpoor spider Aptostichus simus inhabits coastal dunes of southern California and the California Channel Islands (Ramirez 1995).  It lives in burrows concentrated in and about stands of native dune vegetation and extending into the dunes amid litter and the root systems of the plants.”

Thanks so much for the reply! So interesting to learn! 🙂 I just moved out here from NJ and can’t wait to discover more things I didn’t find there!

Letter 7 – Technical Difficulties Solved: Trapdoor Spider Dug Up in Arizona

Ed. Note:  March 22, 2017
We are currently experiencing technical difficulties and we cannot upload any new images.  Please be patient while we research this problem.

Subject: Trapdoor Spider?
Location: North of Tucson, Arizona, USA
March 19, 2017 6:58 pm
She wasn’t too happy to be shoveled out of my garden while I was pulling up weeds and turning soil.
She was clinging to a strip of silk “fabric”, so I’m guessing she’s a trapdoor spider? I’ve never seen one outside one of their holes before.
Signature: Ema

Dear Ema,
We love digging up critters in the garden.  Earlier this year, we were pulling out weeds and we discovered a California Slender Salamander.  We agree this is a female Trapdoor Spider.  We will attempt to identify the species.  Though the face is not showing on your individual, it resembles this Red Moustached Trapdoor Spider on Arachnoboards.  This might be a member of the genus Ummidia as pictured on BugGuide.

Letter 8 – Piotr Naskrecki encounters World’s Largest Spider in Guyana

October 18, 2018
Aloha Daniel –
Thought you’d enjoy this story, if you’ve not seen it before.
http://news.yahoo.com/goliath-encounter-puppy-sized-spider-surprises-scientist-rainforest-125720953.html

Ed. Note:  Piotr Naskrecki frequently helps us identify exotic Katydids.

Letter 9 – Possibly Pale Wishbone Spider from Australia

Subject:  Rare pale wishbone spider
Geographic location of the bug:  Adelaide hills
Date: 05/04/2019
Time: 03:10 AM EDT
Your letter to the bugman:  Hi daniel, i think this
Is a pale wishbone spider can you confirm? Also i didnt kill this arafhnid because i love animals and bugs way too much lol also what insect/arachnid is its fav food And it looks like a mouse spider so how bad is the venom?
How you want your letter signed:  Cael Gallery

Dear Cael,
We cannot say for certain that this is a Pale Wishbone Spider, but it surely resembles the individual pictured on the Arachne.org.au where it states:  “Wishbone spiders are mostly medium-sized mygalomorphs, similar to funnelwebs, but with a golden or silvery look due to fine hairs on the head. They cannot climb smooth vertical surfaces. They have two small spinnerets seen at the rear end of the body, usually pointing up. Their name is derived from their Y shaped shallow burrows, to about 40cm deep, with one arm slightly concealed below the surface of the soil. The Main entrance is lightly covered with silk but has no door.”  Elsewhere on Arachne.org.au, Pale Wishbone Spiders in the genus Aname are described as:  “A medium to large mygalomorph spider with an open burrow, in drier parts of Australia. The burrow is sometimes raised at the surface and shallow, Y shaped, lined with silk, and inclined perhaps to a depth of 40cm at most. This spider has a pale carapace, unusual for Aname, which usually are black spiders. Males have a long spine at the middle of the tibia, the shin section on the first leg, and are quick to rise to the defensive pose. The spinnerets project some distance beyond the rear, usually straight out.”

Ok Thank you, I am only 11 so not the best at identifying but I’m gonna pat myself on the back for getting that far lol

Reader Emails

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

Letter 1 – Trapdoor Spider

Subject:  California trapdoor spider.
Location:  Hoodsport Washington State
Date: 09/19/2017
Time: 04:46 PM EDT
I found this very large fellow above my bed during the night. Caught him in my hat box and put him out in my woodsey rain forest today. So silly question, will there be more? And is he a agrressive bitter?
Signature:  dena williams

Dear dena,
We do not believe you encountered a California Trapdoor Spider as BugGuide data only indicates a range within California.  We suspect you might have encountered Antrodiaetus another member of the same family that we found pictured on BugGuide, and that is reported from Washington by a BugGuide contributor.  Trapdoor Spiders are not aggressive, though we suspect the female may attack to protect her brood.