shamrock orbweaver

(Araneus trifolium)

Conservation Status
shamrock orbweaver
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

     
  Minnesota

not listed

     
           
           
           
           
           
           
           
 
Description
 
 

There are about 650 species in the genus Araneus. Shamrock orbweaver is the largest of these in Minnesota. It occurs across the United States and Canada. It is common in Minnesota. Its large, vertical, circular web is found between between plants, often goldenrods, between 20 to 80 off the ground.

The female is ¼ to ¾ (6 to 20 mm) in length. The male is much smaller, ¾ to 19 16 (20 to 40 mm) long.

The front part of the body (cephalothorax) of the female is medium length to long. The hardened plate (carapace) covering the cephalothorax is light brown with a black stripe in the center and another on each side.

The back part of the body (abdomen) is oval to spherical. It has no humps and no angles toward the front. The upper side of the abdomen highly variable in color and may be light, medium, or dark. It is often reddish but may be purplish, greenish, brownish, or off-white. There are numerous angular white spots and four small, round, black spots. The black spots are always paired with white spots. On medium and dark specimens, the white spots are bordered with a contrasting dark color. On light specimens they are not visibly bordered.

The legs are light brown and medium length to long. They have many conspicuous, highly contrasting, dark bands.

The male has a smaller and has a narrower abdomen and longer legs.

 
     
 

Size

 
 

Female Body Length: ¼ to ¾ (6 to 20 mm)

Male Body Length: 3 16 to ½ (5 to 13 mm)

Legspan: ¾ to 19 16 (20 to 40 mm)

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Tall grasses, shrubs, and trees in meadows and woodland edges; gardens, eaves of buildings, and fences

 
     
 
Biology
 
 

Season

 
 

Mature spiders from August to October

 
     
 

Behavior

 
 

The female spins a large circular web that hangs vertically. This web is called an “orb”, which gives this family of spiders its common name. The orb is typically a closed hub, 20 to 30 in diameter, with 15 to 35 spokes (radii) that are not sticky. The radii extend to the center of the hub. They are connected to each other by sticky threads that spiral outward from the center. The spider also makes a retreat out of silk near one edge of the orb. The retreat is connected by a signal thread to the center of the web, allowing the spider to feel vibrations of prey. The spider spends much of its time in the retreat, especially in the hot midday hours. The web is usually consumed and a new web constructed each evening.

Females catch medium-sized and large insects, even insects larger than themselves. They ignore smaller insects. Males are not able to catch prey larger than themselves.

 
     
 

Life Cycle

 
 

Several hundred orange eggs are deposited in a mass and then wrapped in silk producing a flattened spherical egg sac about 1 in diameter. The egg sac is then attached to nearby vegetation or to the spider’s retreat. Some eggs hatch in the fall, others overwinter in egg sacs. Spiderlings disperse by “ballooning”. They climb a branch, blade of grass, or fencepost, and release a long thread of silk. The silk thread catches the wind or even a light breeze and the spiderling floats to a new site.

 
     
 

Food

 
 

Large and small flying insects

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 29, 30, 82.
 
  10/5/2021      
         
 

Occurrence

 
 

Common and widespread

 
         
 
Taxonomy
 
  Class Arachnida (arachnids)  
 

Order

Araneae (spiders)  
 

Suborder

Araneomorphae (typical spiders)  
  Infraorder Entelegynae (eight-eyed spiders)  
  Superfamily Araneoidea (araneoid spiders)  
 

Family

Araneidae (orb weavers)  
 

Subfamily

Araneinae (typical orbweavers)  
 

Genus

Araneus (angulate and roundshouldered orbweavers)  
       
 

Synonyms

 
 

Aranae trifolium

 
       
 

Common Names

 
 

pumpkin spider

shamrock orbweaver

shamrock spider

 

 

 

 

 

 

 

 

Glossary

Carapace

The hard, upper (dorsal), shell-like covering (exoskeleton) of the body or at least the thorax of many arthropods and of turtles and tortoises.

 

Cephalothorax

The front part of a spider’s body, composed of the head region and the thoracic area fused together. Eyes, legs, and antennae are attached to this part.

 

 

 
 
Visitor Photos
 
           
 

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Samantha Reigel

 
    shamrock orbweaver      
 

Jessica Torres

 
 

on my frontdoor 10/3/2021

 
    shamrock orbweaver   shamrock orbweaver  
           
    shamrock orbweaver   shamrock orbweaver  
 

Alfredo Colon

 
    shamrock orbweaver   shamrock orbweaver  
           
    shamrock orbweaver      
 

Julie Swanson

 
 

Found in the doorway of my husband's hunting shack when my head ran into the web. Ew.

 
    shamrock orbweaver      
 

Katie Schmidt

 
 

I first observed 'Lilith' on July 25th.

She has taken up residence on the door of our back deck. My family and I have been watching her, daily, and she has become like a family member! My 4 year-old, my 13 year-old, and my husband all thought I was crazy for becoming attached to her, but now they are, too!

Attached are some photos we've taken since we realized we were sharing a living space.

  shamrock orbweaver  
           
    shamrock orbweaver   shamrock orbweaver  
           
    shamrock orbweaver      
           
 
MinnesotaSeasons.com Photos
 
 

 

 
           
           

 

Camera

     
 
Slideshows
 
 
     
     
     

 

slideshow

       
 
Visitor Videos
 
       
 

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Other Videos
 
  Fall Hunt For Large Shamrock Spider
Bob TheSpiderHunter
 
   
 
About

Published on Sep 30, 2013

Well, I went out to a new prairie in search of the Shamrock orb-weaver spider (Araneus trifolium) as I have not been able to find a single one in my regular places I visit. But I was successful and had a nice hunt and found my prize spider! Brought a couple home for some more filming and then will be returning them to their webs.

   
  Araneus Trifolium Takes On Large Bumblebee
IloveSPIDERZ
 
   
 
About

Published on Aug 27, 2015

Funny thing... The bumblebee is so large, and the shamrock spider is so (for lack of a better term) fat, she was struggling to wrap up this bee... So instead, she gives up wrapping and gives it a single venomous bite for 20 minutes until the bee is finally dead. I've been bit by these spiders a couple times (Yes, it was entirely my fault... Don't handle them roughly like I did), and it is not pleasant! They have a lot of power in those fangs!

   
       

 

Camcorder

 
 
Visitor Sightings
 
           
 

Report a sighting of this arachnid.

 
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Simply email us at info@MinnesotaSeasons.com.
Be sure to include a location.
 
 

Samantha Reigel
10/5/2021

Location: Deer River, MN

Found in our lilac bush

shamrock orbweaver

 
 

Jessica Torres
10/5/2021

Location: Cloquet MN, Carlton Co., FDL REZ

crazy looking had ex take it

shamrock orbweaver

 
 

Julie Swanson
7/12/2021

Location: St. Louis County, Buick, MN

Found in the doorway of my husband's hunting shack when my head ran into the web. Ew.

shamrock orbweaver

 
  Katie Schmidt
7/25 - 8/15/2020

Location: Nisswa, MN

I first observed 'Lilith' on July 25th. She has taken up residence on the door of our back deck. My family and I have been watching her, daily, and she has become like a family member! My 4 year-old, my 13 year-old, and my husband all thought I was crazy for becoming attached to her, but now they are, too!

Attached are some photos we've taken since we realized we were sharing a living space.

shamrock orbweaver

 
  Alfredo Colon
9-3 to 9-5-2019

Location: Woodbury, Minnesota

shamrock orbweaver

 
  Alfredo Colon
8/12/2018

Location: Woodbury, Minnesota

shamrock orbweaver

 
           
 
MinnesotaSeasons.com Sightings
 
 

 

 

 

 

Binoculars


Created: 4/25/2019

Last Updated:

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