sigmoid prominent

(Clostera albosigma)

sigmoid prominent
Photo by David Israel
  Hodges #

7895

 
 
Conservation Status
  IUCN Red List

not listed

     
  NatureServe

N5 - Secure

     
  Minnesota

not listed

     
           
           
           
           
 
Description
 
 

Sigmoid prominent is a medium-sized, heavy-bodied, nocturnal moth. It is the most common of the four Clostera species found in Minnesota. The species name albosigma means “white S” and refers to the prominent curved marking on the forewing. Spring individuals are darker with more highly contrasting markings. Summer individuals are paler and less conspicuously marked.

The top of the head, the collar, and the top of the thorax are dark brown. The rest of the body is lighter grayish-brown. The male has a dark brown tuft at the tip of the abdomen.

The forewing is grayish-brown. The forewing is slightly concave on the costal (leading) margin and is rounded at the tip. It is crossed by four pale lines, the basal, antemedial, median, and postmedial lines. The antemedial and median lines are parallel and nearly straight. The median line is broken and does not reach the costal margin. The postmedial line is angled backward, forming a “V” with the median line at the inner margin, and forming a prominent white “S”-shaped bar approaching the costal margin. The white bar sharply delineates a dark reddish-brown or chestnut brown area. The cubitus (Cu) vein appears 3-branched.

The hindwing is nearly evenly grayish-brown without contrasting markings. The subcostal (Sc) vein and the anterior branch of the radius (R1) are fused together. The Sc+R1 and radial sector (Rs) are close together and parallel to at least the basal half of the anterior side of the discal cell then diverge.

The male antennae are comb-like with teeth-like structures on both sides. The female antennae are thread-like.

The caterpillar is stout and up to 13 16 long. It has a dark, proportionally large head, and there is usually a pale brown spot above the face (frons). The thorax and abdomen are yellowish-buff and covered with downy, pale hairs (seta). Between the first thoracic segment (T1) and the second abdominal segment (A2) there are four indistinct orange or yellow lines separated by even more indistinct charcoal lines. There is a black knob on A1 that is nearly twice as large as a similar knob on A8. There is a broad, dark gray subdorsal stripe and a broad orange spiracular stripe. Mature caterpillars are seen from May to November.

 
     
 

Size

 
 

Total Length: to ¾

Wingspan: 1 to 1½

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Deciduous woodlands and forests, and shrubby wetlands and fields

 
     
 
Biology
 
 

Season

 
 

Mid-May to mid-August. Probably two generations per year.

 
     
 

Behavior

 
 

Adults are active at night and will come to light. They rest with the wings folded tightly around the abdomen, which is raised into the air.

The caterpillar is a solitary feeder. During the day it curls up a leaf of a host plant and sticks it together with silk webbing, make a shelter where it can feed in safety. At night, it feeds in the open. Unlike all other prominents (Family Notodontidae), this species does not squirt acid as a defense.

 
     
 

Life Cycle

 
 

Given the long flying time for this species, there are probably two generations per year in Minnesota.

The pupa overwinters.

 
     
 

Larva Hosts

 
 

Mostly quaking aspen, but also poplar and willow, and sometimes alder, birch, maple, and elm.

 
     
 

Adult Food

 
 

Adults do not feed.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

21, 24, 27, 29, 30, 71, 75.

 
  11/30/2020      
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
 

Order

Lepidoptera (butterflies and moths)  
 

Suborder

Glossata  
 

Infraorder

Neolepidoptera  
  Parvorder Heteroneura  
  No Rank Ditrysia  
  No Rank Obtectomera  
 

Superfamily

Noctuoidea (noctuid moths)  
 

Family

Notodontidae (prominents)  
 

Subfamily

Pygaerinae  
 

Genus

Clostera  
       
 

Synonyms

 
 

Ichthyura albosigma

 
       
 

Common Names

 
 

sigmoid prominent

 
       

 

 

 

 

 

 

 

Glossary

Costal margin

The leading edge of the forewing of insects.

 

Frons

The upper part of an insect’s face, roughly corresponding to the forehead.

 

Seta

A usually rigid bristle- or hair-like outgrowth 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.

 

 

 

 

 

 
 
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David Israel

 
 

At bug light at 22:34

 
    sigmoid prominent   sigmoid prominent  
 

Bill Reynolds

 
  This first image it was trying to mimic a leaf and the second after I disturbed the moth from this side of the barn.   sigmoid prominent  
           
        sigmoid prominent  
           
 
MinnesotaSeasons.com Photos
 
 

 

 
           
           

 

Camera

     
 
Slideshows
 
Sigmoid Prominent - Hodges#7895 (Clostera albosigma)
Andree Reno Sanborn
  Sigmoid Prominent - Hodges#7895 (Clostera albosigma)  
     

 

slideshow

       
 
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Other Videos
 
  Sigmoid Prominent Moth (Notodontidae: Clostera albosigma) Dorsal View
Carl Barrentine
 
   
 
About

Uploaded on Aug 6, 2011

Photographed at Red Wing, Minnesota (04 August 2011). Go here to see the lateral profile of this specimen: http://bugguide.net/node/view/558672

 
       

 

Camcorder

 
 
Visitor Sightings
 
           
 

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  David Israel
5/15/2020

Location: Woodside Township, Otter Tail County

At bug light at 22:34

sigmoid prominent  
  Bill Reynolds
5/16/2017

Location: Pennington Co. Minnesota

This first image it was trying to mimic a leaf and the second after I disturbed the moth from this side of the barn.

sigmoid prominent  
           
 
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Created 5/18/2017

Last Updated:

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