unequal tortoise beetle

(Sumitrosis inaequalis)

Conservation Status
unequal tortoise beetle (Sumitrosis inaequalis)
Photo by Babette Kis
  IUCN Red List

not listed

 
  NatureServe

NNR - Unranked

 
  Minnesota

not listed

 
           
           
           
           
           
           
           
 
Description
 
 

Unequal tortoise beetle is a small leaf-mining beetle. It is common in the United States east of the Great Plains. It is uncommon in the West, on the Great Plains, and in Minnesota.

Adults are very small, to 3 16 (3.5 to 4.4 mm) long. The body is elongated and nearly parallel-sided, only slightly widened toward the rear. The coloration is variable.

The hardened plate on the upper side of the thorax (pronotum) is wider than long but narrower than the base of the hardened forewings (elytra), brownish-yellow, and dotted with deep pits (punctate).

The elytra have are brownish-yellow with several black spots and rows of punctures bordered by distinct ridges. The margins of the elytra are toothed (serrated). The pattern of spots distinguishes this beetle from other species in the same genus.

The head is brownish yellow. The eyes are large and black and are not notched. The mouth parts are small. The antennae are black, have eight segments, and are short, less than half as long as the body.

The legs are light brownish-black. The last part of each leg (tarsus), corresponding to the foot, is black and has five segments. The fourth segment is very short and is concealed within the broadened tip of the third segment, making the tarsus appear to have only four segments.

The coloration of the head, pronotum, and elytra is variable. The black spots may be small and sharply defined, or large, fuzzy, and merging with adjacent spots. A dark form of this beetle has the colors reversed, with light spots on a dark background.

 
     
 

Size

 
 

Total length: to 3 16

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

 

 
     
 
Biology
 
 

Season

 
 

 

 
     
 

Behavior

 
 

The larvae are leaf miners. They feed between the upper and lower leaf surfaces.

 
     
 

Life Cycle

 
 

 

 
     
 

Larva Food

 
 

Leaves of various plants in the aster (Asteraceae) family, including:

aster (Symphyotrichum)
boneset (Eupatorium)
coneflower (Rudbeckia)
goldenrod (Solidago)
ironweed (Vernonia)
ragweed (Ambrosia)
sunflower (Helianthus)

Possibly also plants in the Pea (Fabaceae) family.

 
     
 

Adult Food

 
 

Leaves of various woody and herbaceous plants, including:

black locust (Robinia)
elm (Ulmus)
fir (Abies)
leatherleaf (Chamaedaphne)
milkweed (Asclepias)
nightshade (Solanum)
oak (Quercus)
partridge pea (Chamaecrista)
pine (Pinus)
spruce (Picea)
sumac (Rhus)
willow herb (Epilobium)

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 27, 29, 30, 82.

 
  10/4/2022      
         
 

Occurrence

 
 

 

 
         
 
Taxonomy
 
 

Order

Coleoptera (beetles)  
 

Suborder

Polyphaga (water, rove, scarab, long-horned, leaf, and snout beetles)  
 

Infraorder

Cucujiformia  
 

Superfamily

Chrysomeloidea (leaf beetles and allies)  
 

Family

Chrysomelidae (leaf beetles)  
 

Subfamily

Cassidinae (tortoise and hispine beetles)  
 

Tribe

Chalepini  
 

Genus

Sumitrosis  
       
 

Synonyms

 
 

Anoplitis inaequalis

Sumitrosis arnetti

 
       
 

Common Names

 
 

unequal tortoise beetle

 

 

 

 

 

 

 

 

 

Glossary

Elytra

The hardened or leathery forewings of beetles used to protect the fragile hindwings, which are used for flying. Singular: elytron.

 

Frons

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

 

Pronotum

The exoskeletal plate on the upper side of the first segment of the thorax of an insect.

 

Punctate

Dotted with pits (punctures), translucent sunken glands, or colored spots of pigment.

 

Tarsus

On insects, the last two to five subdivisions of the leg, attached to the tibia; the foot. On spiders, the last segment of the leg. Plural: tarsi.

 

 

 

 

 

 
 
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Babette Kis

 
 

Sumitrosis inaequalis

 
    unequal tortoise beetle (Sumitrosis inaequalis)      
           
 

Sumitrosis inaequalis, on aster sp,. Barnes Prairie, Racine Co., WI June 9, 2021.

 
    unequal tortoise beetle (Sumitrosis inaequalis)   unequal tortoise beetle (Sumitrosis inaequalis)  
 

Alfredo Colon

 
    unequal tortoise beetle (Sumitrosis inaequalis)      
           
 
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  Babette Kis
6/9/2021

Location: Barnes Prairie, Racine Co., WI

Sumitrosis inaequalis, on aster sp,. Barnes Prairie, Racine Co., WI June 9, 2021.

unequal tortoise beetle (Sumitrosis inaequalis)  
  Babette Kis
6/7/2021

Location: Barnes Prairie, Racine Co., WI

unequal tortoise beetle (Sumitrosis inaequalis)  
  Alfredo Colon
6/8/2018

Location: Woodbury, MN

unequal tortoise beetle (Sumitrosis inaequalis)  
           
 
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Created 11/1/2018

Last Updated:

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