Barn Spider Male vs Female: Uncovering Their Differences

Barn spiders are fascinating creatures that vary in size and appearance based on their gender.

While both male and female barn spiders share some similarities, there are some distinct differences that researchers and arachnid enthusiasts find intriguing.

Female barn funnel weavers range from 7.5 to 11.5 millimeters, while males are typically smaller, measuring between 6 and 9 millimeters in length.

Females exhibit a red-brown cephalothorax adorned with pale-yellow hairs, while males appear less vibrant, often displaying more subdued colors.

Barn Spider Male vs Female
Possibly Barn Spider

The abdomen of a female barn spider can range from pinkish to pale flesh in color, whereas males may have more of a khaki to amber tone.

With unique patterns and variations in size, understanding the differences between male and female barn spiders is essential for those interested in their biology and behavior.

As we delve deeper into the world of barn spiders, we can continue to marvel at the range of attributes that make these arachnids such a captivating subject.

Barn Spider Male vs Female: Sexual Dimorphism

Male vs Female Appearance

In barn spiders, sexual dimorphism is evident in their appearance. Males and females differ in size, color, and body proportions.

  • Males: Generally smaller than females, slender abdomen
  • Females: Larger than males, bigger and rounder abdomen

These differences contribute to their respective roles in reproduction and survival.

Palps

The most noticeable difference between male and female barn spiders is their palps, which are the sensory and reproductive organs.

  • Male palps: Elaborate, enlarged, and often equipped with specialized structures for sperm transfer
  • Female palps: Smaller and simpler, primarily used for sensory purposes

Barn Spider

Size and Color Differences

Barn spiders exhibit significant size and color differences between the sexes.

Size

 MaleFemale
SizeSmallerLarger

Males are typically smaller (around 5.6 mm) while females are somewhat bigger (averaging 6.9 mm) according to a study.

Color

 MaleFemale
ColorDullerBrighter

In general, males exhibit duller colors, while females display brighter and more vibrant coloration, which could be attributed to sexual selection.

Comparison of Male and Female Barn Spiders:

FeatureMaleFemale
Body length6-9 mm7.5-11.5 mm
Body colorRed-brownRed-brown
Web buildingYesYes

Reproduction

Mating Season

Barn spiders (Araneus cavaticus), part of the Araneidae family, typically have a mating season during late summer and early fall.

During this time, male barn spiders search for receptive females to mate with.

Egg Sacs and Spiderlings

After mating, female barn spiders create egg sacs to protect their eggs. They can produce multiple egg sacs, each containing up to several hundred eggs.

Once the eggs hatch, the young spiders, called spiderlings, emerge from the sac. Some interesting features of egg sacs include:

Possibly Barn Spider

  • Made of silk
  • Protective outer layer
  • Can contain hundreds of eggs

Life Cycle

The life cycle of barn spiders is relatively short. Here is a brief overview of their life cycle.

  • Egg: Inside the egg sac, protected until hatching
  • Spiderling: Newly hatched spiders that will eventually leave the sac
  • Juvenile: Growing spiders that undergo several molts until reaching adulthood
  • Adult: Mature spiders capable of reproduction
Life StageDuration
Egg2-3 weeks
Spiderling2-3 weeks
Juvenile5-6 months
Adult3-4 months

Compared to other arachnid species such as scorpions and orb weavers, barn spiders have a shorter life cycle and lifespan.

For example, some orb weavers can live up to a year, while scorpions can live for several years. This is a key difference between barn spiders and other species within the Araneidae family.

Barn spider male vs female role in reproduction

  • Male barn spiders have longer legs but smaller bodies than females
  • Females typically have larger abdomens to carry eggs
  • Coloration and markings can vary, but both genders have similar patterns

Comparison table:

FeatureMale Barn SpiderFemale Barn Spider
Leg lengthLongerShorter
Body sizeSmallerLarger
Abdomen sizeSmallerLarger (egg-carrying)

Conclusion

Barn spiders, scientifically known as Araneus cavaticus, exhibit distinct differences between males and females.

While both genders share some similarities, their size, coloration, and body markings set them apart. Females, larger in size, range from 7.5 to 11.5 millimeters, while males measure between 6 and 9 millimeters.

The coloration of females is often brighter, with males displaying more subdued hues. A significant distinction lies in their palps, with males having elaborate structures for sperm transfer.

These spiders play a pivotal role in the ecosystem, controlling insect populations and serving as natural pest control.

Their presence in popular culture, notably in E.B. White’s Charlotte’s Web, underscores their significance and the need for conservation.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about barn spiders.

Scroll down to have a look at some of them.

Letter 1 – Barn Spider

Huge Scary Spider, I’m shaking as I type this!
Hello,
I am from Austin, Texas and we have a very scary spider we’ve been keeping alive (sometimes even feeding it!) on our wooden porch Might I add that this area is wooded with no water close by.

His/Her web is a typical spider’s web you see in movies, not a funnel web or an orb web. It usually only comes out at night, burrowing between the metal and the glass during the day. It also usually sits with its legs drawn in.

Today I got a special treat, because it had just finished with its molting phase and its web was disturbed so its legs were extended and it out during the day to pose for my camera.

The pictures lighten its abdomen markings as they are more of a dark brown with visible hairs, and there are dark brown and white stripes on his legs. In addition his butt is kind of raised up, in the shape of a tear drop.

Might I add that I just went outside to check on it, and it jumped from the wall, falling to the ground. I’ve never noted aggressive behaviour before like this, nor have I seen it jump before. I’m so scared now because its very fast, and when its legs are extended, its larger than a half dollar.
Please help!
Rissa
PS, I took a picture of the molted shell, and feel free to edit any of this!

Hi Rissa,
You have a Barn Spider, Araneus cavaticus. The spider builds a large orb web at night and stands in it, but generally seeks shelter above the web during the day. It is usually found in shady locations.

Letter 2 – Barn Spider

Subject: Spider help!
Location: Northeast, USA
September 7, 2014 8:32 pm
Hi there,
Hoping you can help me identify this big guy. We just moved from Brooklyn to upstate NY (Gansevoort just north of Saratoga Springs to be exact), and we have found 3 of these large spiders hanging around the house/porch.

They are about the size of my palm with legs outstretched– big and scary! My main concern is our 2 yr old daughter– are these guys poisonous?
Many thanks in advance for your help,
Sue
(today’s date is Sept. 7th)
Signature: Sue

Barn Spider
Barn Spider

Dear Sue,
This is an Orbweaver in the family Araneidae, and we are nearly certain it is a Barn Spider,
Araneus cavaticus, a conclusion we reached upon comparing your image to this image on BugGuide. 

The information page on BugGuide notes:  “This is the spider in the book Charlotte’s Web by E.B. White. The spider’s full name is Charlotte A. Cavatica.”  Of the entire family, BugGuide notes:  “Orb weavers are very docile, non-aggressive spiders that will flee at the first sign of a threat (typically they will run or drop off the web).

They are not dangerous to people & pets, and are actually quite beneficial because they will catch and eat a lot of pest-type insects. ” 

Like most spiders, Orbweavers have venom, but it is not considered highly toxic to humans, and in the unlikely event that a bite does occur, the symptoms are usually not much more than local swelling, redness and tenderness that quickly pass with no lasting effects.

Hi Daniel,
Thank you so much for taking the time to write me back.  Such a relief to know all of this info!  From the image / link you sent, I agree, it does look like a barn spider. 

So glad to know they’re basically harmless– the ones we saw were pretty big and intimidating, but sounds like they’re the gentle giant types.
Many thanks again,
Sue

Authors

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  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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