Milbert’s tortoiseshell

(Aglais milberti)

               
Conservation Status

IUCN Red List

not yet assessed

Milbert’s tortoiseshell

NatureServe

N5 - Secure

S5 - Secure

Minnesota

not listed

Occurrence

Fairly common

Flight/Season

Two broods: Mid-June to mid-August; and early September to late October and April to early May (hibernating)

Habitat

Woodland openings; moist fields, meadows, and pastures near woodlands; streamsides; trails; and roadside ditches.

Size

Wingspan: 1 to 2½

Photo by Nicole Vasquez

Identification

This is a medium-sized brushfooted butterfly. It has a wingspan of 1 to 2½. Males and females look alike.

The upperside of both wings is dark brown from the base to the postmedian band; has a broad, bright orange submarginal band that grades to yellow toward the inner edge; and a narrow black marginal band. The tip of the forewing is squared off. The forewing has two orange patches on the leading edge of the basal area, and a dark brown patch and white spot on the leading edge of the subapical band. The marginal band of the forewing has row of pale crescent-shaped to irregular spots. Some of the marginal spots on the hind wing may be light blue. Overwintering individuals emerging from hibernation are paler and appear tattered.

The underside of both wings is dark brown with a broad, lighter brown submarginal band

The caterpillar is black above, pale below, and up to 1 long. The spiracles are black with a broad white border. There is a row of pale, yellowish crescents below the spiracles that may be joined to form a lateral stripe. The thorax and abdomen are covered with numerous, pale, straight, hair-like structures (seta). The broad base of the seti are pale, making the body look speckled. On the thorax and each abdominal segment there is a long, thick, stiff spine (scolus) in the middorsal, subdorsal, and supraspiracular regions. The scoli are not obviously branched. The head is black and is covered with a mix of both black and white hairs but no scoli. The anterior leg-like structures (prolegs) are pale. The thoracic legs and the anal proleg are black.

Mature caterpillars are found in spring and again in early summer.

 
Similar
Species

No similar species


Larval Food

In Minnesota, only stinging nettle

 
Adult Food

Mostly flower nectar, but also sometimes sap, rotting fruit, and dung.

 
Life Cycle

The female lays bunches of usually 50 to 150 but up to 900 green, cone-shaped eggs on the undersides of stinging nettle leaves. When the eggs hatch the first instar caterpillars form a silky communal web in which they feed. Mature instars are solitary. They create individual silky nests on a folded leaf and feed alone.

There are two broods each year. Adults of the second brood hibernate, sometimes in groups, in bark crevices or on human structures.

 
Behavior

The male will perch to watch for passing females.


Distribution Distribution Map  

Sources: 20, 21, 24, 29, 71.


Comments

 


Taxonomy

Order:

Lepidoptera (butterflies and moths)

 

Suborder:

Glossata

 

Infraorder:

Neolepidoptera

 

Parvorder:

Heteroneura

 

No Rank:

Ditrysia

 

No Rank:

Obtectomera

 

Superfamily:

Papilionoidea (butterflies [excluding skippers])

 

Family:

Nymphalidae (brush-foots)

 

Subfamily:

Nymphalinae (true brushfoots)

 

Tribe:

Nymphalini

 
Subordinate Taxa

Milbert’s tortoiseshell (Aglais milberti milberti)

Milbert’s tortoiseshell (Aglais milberti pullum)

Milbert’s tortoiseshell (Aglais milberti subpallida)

Milbert’s tortoiseshell (Aglais milberti viola)

 
Synonyms

Nymphalis milberti

 
Common
Names

Milbert’s tortoiseshell


 

 

 

 

 

 

Glossary

instar

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

 

proleg

A fleshy structure on the abdomen of some insect larvae that functions as a leg, but lacks the five segments of a true insect leg.

 

scolus

Plural: scoli. A spiny, branched projection from a larval body wall, the branches terminating with a single stiff, hair-like or bristle-like tip.

 

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.

Nicole Vasquez


Mixed in with Painted Ladies on flowering Sedum

  Milbert’s tortoiseshell    

Bill Reynolds


  Milbert’s tortoiseshell    

       
       
       

MinnesotaSeasons.com Photos

   
       
       

 

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Slideshows

   
  Milbert's Tortoiseshell
DianesDigitals
 
  Milbert's Tortoiseshell  
 
About

Copyright DianesDigitals

 
     
  Milbert's Tortoiseshell (Aglais milberti)
Andree Reno Sanborn
 
  Milbert's Tortoiseshell (Aglais milberti)  
     
  Aglais milberti
wetvideocamera
 
   
 
About

Published on Jan 8, 2014

Milbert's Tortoiseshell

 
     

 

slideshow

     

Visitor Videos

   
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Other Videos

 
  Milbert's Tortoiseshell - Cypress Hills, Alberta
wetvideocamera
 
   
 
About

Uploaded on Apr 16, 2011

Milbert's Tortoiseshell Butterfly seen near Elkwater, Alberta in the Cypress Hills.

( Aglais milberti ) May 2004

 
     
  Milbert's Tortoiseshell Caterpillars on Stinging Nettle
Todd Stout
 
   
 
About

Uploaded on Aug 12, 2011

(Please forgive the lousy audio.) Differentiating Milbert's Tortoiseshell larval nests vs. Red Admirals larval nests on stinging nettle is not too difficult because of the incredible levels of feeding damage that Milbert's Tortoiseshell caterpillars cause. This occurs because female Nymphalis milberti lay their eggs in clutches of over 100 eggs. By the time these larvae grow to maturity, their incredible feeding damage is obvious on the host plant.

 
     
  Milbert's Tortoiseshell Butterfly emerges in time lapse
JCMegabyte
 
   
 
About

Uploaded on Jan 30, 2007

This Milbert's Tortoiseshell (Nymphalis milberti) emerges in this time lapse sequence. Actual time is about 2-3 minutes. Much more butterfly/moth video, photography and life cycle studies available free to the public at HTTP://jcmdi.com

 
     
  フルHDでムビる00785 ヤンキーコヒオドシ♂
alwaysartzone
 
   
 
About

Published on Jul 23, 2012

フルHDでムビる00785 ヤンキーコヒオドシ♂

Aglais milberti male

2012-07-12:in Canada (Emerald Lake)

 
     
  Finding satyr comma and milbert's tortoiseshell caterpillars on stinging nettle
indroid2
 
   
 
About

Uploaded on Jul 2, 2009

This video reviews the different nests and larval preferences of the milbert's tortoiseshell (Nymphalis milberti) and the satyr comma (Polygonia satyrus neomarsyas) on stinging nettle (Urtica dioica.) Warning! Handling stinging nettle with your bare hands can be painful. Handle with gloves!

 
     

 

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Visitor Sightings

   
Share your sighting of this insect.

Nicole Vasquez
9/17/2017

Location: Silver Bay, MN Lake Country

Mixed in with Painted Ladies on flowering Sedum

Milbert's tortoiseshell


Bill Reynolds
7/14/2014

Location: Pennington Co MN

 

Milbert's tortoiseshell


     
     
 

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