shamrock orbweaver

(Araneus trifolium)

               
Conservation Status

IUCN Red List

not listed

shamrock orbweaver

 

NatureServe

NNR - Unranked

Minnesota

not listed

Occurrence

Common and widespread

Season

Mature spiders from August to October

Habitat/Host

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

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)

          Photo by Alfredo Colon

Identification

There are about 650 species in the genus Araneus. Shamrock orbweaver is the largest 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 and light brown and medium to long. They have many conspicuous, highly contrasting, dark bands.

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

 
Similar
Species

 


Food

Large and small flying insects

 
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.

 
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.


Distribution Distribution Map   Sources: 24, 29, 30.

Comments

 


Taxonomy

Order:

Araneae (spiders)

 

Suborder:

Araneomorphae

 

No Rank:

Entelegynae (eight-eyed spiders)

 

No Rank:

Orbicularia

 

Superfamily:

Araneoidea

 

Family:

Araneidae (orb weavers)

 
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.

 

 

       

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Alfredo Colon


  shamrock orbweaver   shamrock orbweaver

       
       

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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!

 
     

 

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Alfredo Colon
8/12/2018

Location: Woodbury, Minnesota

shamrock orbweaver


     
     
 

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