Isabella tiger moth

(Pyrrharctia isabella)

               
Hodges #

8129

Isabella tiger moth
Conservation Status

IUCN Red List

not yet assessed

NatureServe

N5 - Secure

Minnesota

not listed

Occurrence

Widespread and common

Flight/Season

One brood. Early June to late July.

Habitat

Deciduous woodlands, prairies

Size

Wingspan: 1¾ to 2½

Total Length: 15 16 to 15 16

          Photo by Bill Reynolds

Identification

In its larval (caterpillar) stage, this tiger moth may be the most widely recognized moth in North America. The adult is less conspicuous but equally distinctive.

The caterpillar is up to 2 long and is densely covered with stiff bristles (setae) from front to back. There are also a few longer, softer hairs extending from the front and back of the body. The setae are in clusters of several and are mostly uniform in length. On most caterpillars the setae are black on the head, thorax, and first few and last few abdominal segments; and orange on the middle abdominal segments. As the caterpillar ages and grows, it sheds its skin and setae (molts) several times. At each successive stage between molts (instar) it becomes more orange. On some individuals all of the setae are blond, brown, rust, or tan. There is a small breathing hole (spiracle) on both sides of each thoracic segment and all but the last abdominal segment. On pale individuals the spiracles are tan or white.

The adult moth has a wingspan of 1¼ to 2 and a total length of 15 16 to 15 16. The thorax is densely covered with long brown or yellowish-brown hairs. The abdomen is orange with an upper (dorsal) row of black spots.

The forewings are pointed and are uniformly light to medium orangish-brown. On some individuals there is a fringe of reddish-orange hairs on the outer margin. The veins are marked with faint brown spots. There is a series of black spots on the subterminal line and often one or more spots on the antemedial, median, and postmedial lines. The discal spot has a group of 3 to 5 black spots. The hindwing of males are pale orange with a black discal spot and black spots near the margin. The hindwing of females is pale rose but otherwise similar.

 
Similar
Species

 


Larval Food

Deciduous trees and a wide range of low growing herbaceous and woody plants.

 
Adult Food

Adults do not feed.

 
Life Cycle

Eggs hatch after about two weeks. Caterpillars overwinter under leaf litter or other debris, where they freeze solid. In the spring they become active and resume feeding. After a few days then spin a cocoon to pupate. Adults emerge in about a month.

 
Behavior

Caterpillars are especially mobile in the fall. When disturbed, they curl up into a ball.

Adults are nocturnal. They are attracted to lights.


Distribution Distribution Map  

Sources: 7, 21, 24, 29, 71, 75.


Comments

Winter Forecast
Folklore says that the size of the orange band predicts the severity of the coming winter, with wider bands forecasting a milder winter. This means of forecasting is probably as accurate as the Farmer’s Almanac, though perhaps not as accurate as the National Weather Service.


Taxonomy

Order:

Lepidoptera (butterflies and moths)

 

Suborder:

Glossata

 

Infraorder:

Neolepidoptera

 

Parvorder:

Heteroneura

 

No Rank:

Ditrysia

 

No Rank:

Obtectomera

 

Superfamily:

Noctuoidea (noctuid moths)

 

Family:

Arctiidae (tiger moths and lichen moths)

 

Subfamily:

Arctiinae (tiger moths)

 

Tribe:

Arctiini

 

Subtribe:

Spilosomina

 
Synonyms

Isia isabella

 
Common
Names

banded woollybear

black-ended bear

Isabella tiger moth

woolly bear


 

 

 

 

 

 

 

Glossary

instar

The developmental stage of arthropods between each molt; in insects, the developmental stage of the larvae or nymph.

 

seta

A usually rigid bristle- or hair-like structure on butterflies and moths used to sense touch. Plural: setae.

 

spiracle

A small opening on the surface of an insect through which the insect breathes.

 

 

 

 

 

       

Visitor Photos

   
Share your photo of this insect.

Bill Reynolds


  Isabella tiger moth   Isabella tiger moth
       
  Isabella tiger moth    

       
       
       

MinnesotaSeasons.com Photos

   
       
       

 

Camera

     

Slideshows

   
  Isabella Tiger Moth
DianesDigitals
 
  Isabella Tiger Moth  
 
About

Copyright DianesDigitals

 
     
  Woolly Bear Caterpillar
Andree Reno Sanborn
 
  Woolly Bear Caterpillar  
 
About

Pyrrharctia isabella (larval form)
bugguide.net/node/view/493/bgimage

larva:

adult is the Giant Leopard Moth:
bugguide.net/node/view/493/bgimage

 
     
  Isabella Tiger Moth (Pyrrharctia isabella)
Bill Keim
 
  Isabella Tiger Moth (Pyrrharctia isabella)  
     
  Pyrrharctia isabella (Isabella Tiger Moth)
Allen Chartier
 
  Pyrrharctia isabella (Isabella Tiger Moth)  

 

slideshow

     

Visitor Videos

   
Share your video of this insect.

     
     

Other Videos

 
  Isabella Tiger Moth (Erebidae: Pyrrharctia isabella) Caterpillar
Carl Barrentine
 
   
 
About

Uploaded on Oct 6, 2010

Photographed on a blustery afternoon near Fisher, Minnesota (04 October 2010).

 
     
  Run, Woolly, Run!
SquirrelOnRoad
 
   
 
About

Uploaded on Oct 14, 2008

A Woolly Bear (the caterpillar stage of the Isabella tiger moth, Pyrrharctia isabella) showed up in the yard, so I recorded it running away. Maybe it thought I was a predator. Boy, I've never seen one move so fast!

 
     
  Banded Woolly Bear Caterpillar (Pyrrharctia Isabella)
juniortore1
 
   
 
About

Uploaded on Jan 23, 2012

Just some quick footage of a banded woolly bear caterpillar I rescued from the pool. They turn into a isabella tiger moth.

 
     
  Pyrrharctia isabella (Isabella Tiger Moth)
Barbarossa1863
 
   
 
About

Published on Oct 7, 2012

The adult is the Isabella Tiger Moth and the larva is called the Banded Woolly Bear. The larvae of many species of Arctiid moths are called "woolly bears" because of their long, thick, furlike setae.

------------

Folklore:
Folklore of the eastern United States and Canada holds that the relative amounts of brown and black on the skin of a Woolly Bear caterpillar (commonly abundant in the fall) are an indication of the severity of the coming winter. It is believed that if a Woolly Bear caterpillar's brown stripe is thick, the winter weather will be mild and if the brown stripes are narrow, the winter will be severe. In reality, hatchlings from the same clutch of eggs can display considerable variation in their color distribution, and the brown band tends to grow with age; if there is any truth to the tale, it is highly speculative

 
     
  Wooly bear caterpillar (Pyrrharctia isabella)
erminehustler
 
   
 
About

Published on Oct 4, 2012

Larval form of Isabella's tiger moth. Amherst, VA. Slow speed.

 
     

 

Camcorder

         

Visitor Sightings

   
Share your sighting of this insect.

Bill Reynolds
12/17/2015

Location: Pennington Co. MN

… this fall we had tons of Woolly Bear caterpillars crawling about the yard.

Isabella tiger moth


Bill Reynolds
9/22/2014

Location: Pennington Co. MN

Woolly Worm, the caterpillar stage of the Isabelle Tiger moth.

Isabella tiger moth


     
     
 

MinnesotaSeasons.com Sightings

   


 

 

Binoculars

Last Updated:

About Us | Privacy Policy | Contact Us | © 2017 MinnesotaSeasons.com. All rights reserved.