orbed narrow-wing

(Magusa divaricata)

orbed narrow-wing
Photo by Babette Kis
  Hodges #

9637.1

 
 
Conservation Status
  IUCN Red List

not listed

 
  NatureServe

NNR - Unranked

SNR - Unranked

 
  Minnesota

not listed

 
           
           
           
 
Description
 
 

Orbed narrow-wing, also called variable narrow-wing, is an uncommon, migratory, medium-sized moth. It occurs from southern Canada to central South America.

Orbed narrow-wing adults fly year-round as far north as Texas. They migrate northward every year, bypassing the middle latitudes of the United States. They arrive in Minnesota usually in August or September. They do not migrate south again in the fall, and they do not survive northern winters. Their long-distance migration results in two distinct, widely separated ranges in the U.S. In the northeast they occur from Maine to New Jersey, west to Minnesota and northern Illinois. In the southwest they occur from Texas to eastern Arizona. Between these ranges there is a sprinkling of widely scattered records. Their northern range appears to be expanding, possibly due to the expanding range of their preferred northern host, glossy buckthorn.

Orbed narrow-wing larvae feed on Carolina buckthorn, glossy buckthorn, and possibly other plants in the Rhamnaceae (buckthorn) family. In Minnesota, adults are active from August to October in shrubby areas that contain buckthorn.

Adults are 1116to (18 to 22 mm) in length and have a 1516 to 1¾ (33 to 45 mm) wingspan. Moth size is sometimes given in terms of forewing length, which in this case is to ¾ (15 to 22 mm). The body is long and slender.

The head is prominent. The sensory mouthparts (labial palps) are turned upward and are short, reaching to the middle of the head.

The forewing is long and narrow, three times longer than wide. The outer margin is rounded and is strongly angled toward the inner margin. The coloration is highly variable. The background color is chocolate brown, brownish gray, or blackish brown. The inner half is often a contrasting pale gray or brown. On some individuals, there is a thin, white, longitudinal line in the basal area. The circular spot (orbicular spot) in the upper median area is large, and it is placed lower than usual. The kidney-shaped spot (reniform spot) in the lower median area is large. Both spots are usually conspicuous, usually hollow or pale inside, and always bordered with a narrow black line. The reniform spot is usually also surrounded with an outer, narrow, whitish line. The antemedial (AM) line is scalloped and almost touches the orbicular spot. The postmedial (PM) line is strongly bent upward toward the leading edge (costal margin). Both lines are inconspicuous. There is usually a large, pale, more or less round patch on the costal margin near the wingtip.

The hindwings are a medium to dark shade of the forewing base color. They are somewhat translucent between the veins.

 
     
 

Size

 
 

Total length: 1116to (18 to 22 mm)

Wingspan: 1516 to 1¾ (33 to 45 mm)

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

shrubby areas that contain buckthorn

 
     
 
Biology
 
 

Season

 
 

August to October

 
     
 

Behavior

 
 

Adults are active at night and will come to lights.

 
     
 

Life Cycle

 
 

 

 
     
 

Larva Food

 
 

Carolina buckthorn, glossy buckthorn, and possibly other plants in the Rhamnaceae (buckthorn) family

 
     
 

Adult Food

 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

21, 29, 30, 71, 75, 82, 83.

Records of Magusa orbifera in the United States north of southern Florida prior to 2009 should be considered as to referring to Magusa divaricata.

 
  12/12/2023      
         
 

Occurrence

 
 

Uncommon

 
         
 
Taxonomy
 
 

Order

Lepidoptera (butterflies and moths)  
 

Superfamily

Noctuoidea (owlet moths and allies)  
 

Family

Noctuidae (cutworm moths and allies)  
 

Subfamily

Noctuinae (cutworms and dart moths)  
 

Tribe

Dypterygiini  
 

Genus

Magusa  
       
 

Magusa divaricata was formerly treated as a synonym of Magusa orbifera. It was raised to full species status in 2009. The two species can be reliably differentiated only by microscopic examination of the male genitalia and by location. Magusa orbifera occurs only as far north as southern Florida.

 
       
 

Synonyms

 
 

Magusa dissidens

Magusa sarpida

Stictoptera divaricata

 
       
 

Common Names

 
 

orb narrow-wing moth

orbed narrow-wing

orbed narrow-wing moth

variable narrow-wing

 

 

 

 

 

 

 

 

 

Glossary

Antemedial (AM) line

A thin line separating the basal area and the median area of the forewing of Lepidoptera.

 

Costal margin

The leading edge of the forewing of insects.

 

Orbicular spot

A circular spot or outline in the upper median area near the antemedial line on the forewing of many moths.

 

Palp

Short for pedipalp. A segmented, finger-like process of an arthropod; one is attached to each maxilla and two are attached to the labium. They function as sense organs in spiders and insects, and as weapons in scorpions. Plural: palpi or palps.

 

Postmedial (PM) line

A thin line separating the median area and the postmedial area of the forewing of Lepidoptera.

 

Reniform spot

A kidney-shaped spot or outline in the lower median area near the PM line on the forewing of many moths.

 

 

 

 

 

 
 
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Babette Kis

 
 

Magusa divaricata orbed narrow-wing moth

Magusa divaricata, orbed narrow-wing moth, Milwaukee, WI. The caterpillars eat buckthorn. Photo was taken on Sept. 17, 2021.

  orbed narrow-wing  
           
 
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  Babette Kis
9/17/2021

Location: Milwaukee, WI

Magusa divaricata, orbed narrow-wing moth, Milwaukee, WI. The caterpillars eat buckthorn. Photo was taken on Sept. 17, 2021.

orbed narrow-wing  
           
 
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Created: 12/13/2023

Last Updated:

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