midwestern salmonfly

(Pteronarcys pictetii)

Conservation Status
midwestern salmonfly
  IUCN Red List

not listed

     
  NatureServe

N5 - Secure

SNR - Unranked

     
  Minnesota

not listed

     
           
           
           
           
           
           
 
Description
 
 

Midwestern salmonfly is a large, dark brown, giant stonefly. It is common in the Midwest from Minnesota and Wisconsin south to Kansas and Indiana.

Adults are 1½ to 2½ long. The body is soft, elongated, and flattened.

The head is rounded in front, narrows slightly in the rear, and has a thin, bright orange, rear margin. There are two large compound eyes at the side of the head and three simple eyes (ocelli) in a triangle on top of the head in the middle. The antennae are long and thread-like, and have many segments. The mouthparts are vestigial.

The exoskeletal plate covering the thorax (pronotum) is highly sculptured. It is dark brown with a thin, bright orange, longitudinal stripe in the middle. There are also three bright orange spots at the base.

There is a pair of sensory appendages (cerci) at the end of the abdomen.

There are two pairs of membranous wings. The hindwings fold flat over the body fan-like and cover most of the abdomen. It has many prominent veins and a large anal lobe. The forewings are narrower and longer than the hindwings. It also has many prominent veins, including a series of cross veins between the media vein (M) and the cubitus vein (Cu) and between the first cubitus vein first branch (Cu1) and second branch (Cu2). The are also two rows of two rows of cross veins in the anal area and a row of cross veins between the costa (C), the vein at the leading edge of the wing, and the subcosta (Sc).

The third segment (femur) and fourth segment (tibia) of each leg is robust. There is a pair of claws at the end of each leg.

 
     
 

Size

 
 

Total Length: 1½ to 2½

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Cool, small to medium-sized streams

 
     
 
Biology
 
 

Season

 
 

April to June

 
     
 

Behavior

 
 

Naiads move very slowly. When disturbed they will pretend to be dead. Adults are poor fliers and when disturbed they will run rather than fly away. They are sometimes found far from water. They are active at night (nocturnal) and are attracted to lights.

 
     
 

Life Cycle

 
 

Naiads live in well aerated water and take 2 to 3 years to develop. Adults emerge from April to June and live for only 2 to 3 weeks.

 
     
 

Larva Food

 
 

Particulate plant matter

 
     
 

Adult Food

 
 

Adults do not feed

 
     
 
Distribution
 
 

Distribution Map

 

Sources

7, 27, 29, 30.

Stoneflies of the United States; U.S. Geological Survey

 
  6/8/2019      
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
 

Order

Plecoptera (stoneflies)  
 

Suborder

Systellognatha  
 

Superfamily

Pteronarcyoidea  
 

Family

Pteronarcyidae (giant stoneflies)  
 

Subfamily

Perlodinae  
 

Tribe

Perlodini  
 

Genus

Pteronarcys  
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

midwestern salmonfly

 
       

 

 

 

 

 

 

 

Glossary

Cercus

One of a pair of small sensory appendages at the end of the abdomen of many insects and other arthropods. In Odonata, one of the upper pair of claspers. Plural: cerci.

 

Femur

On insects and arachnids, the third, largest, most robust segment of the leg, coming immediately before the tibia. On humans, the thigh bone.

 

Ocellus

Simple eye; an eye with a single lens. Plural: ocelli.

 

Pronotum

The saddle-shaped, exoskeletal plate on the upper side of the first segment of the thorax of an insect.

 

Tibia

The fourth segment of an insect leg, after the femur and before the tarsus (foot). The fifth segment of a spider leg or palp.

 

 

 

 

 

 
 
Visitor Photos
 
           
 

Share your photo of this insect.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach one or more photos and, if you like, a caption.
 
           
 
MinnesotaSeasons.com Photos
 
    midwestern salmonfly   midwestern salmonfly  
           

 

Camera

     
 
Slideshows
 
 
     
     
     

 

slideshow

       
 
Visitor Videos
 
       
 

Share your video of this insect.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Attach a video, a YouTube link, or a cloud storage link.
 
 

 

 
     
     
       
       
       
 
Other Videos
 
     
     
     
       

 

Camcorder

 
 
Visitor Sightings
 
           
 

Report a sighting of this insect.

 
  This button not working for you?
Simply email us at info@MinnesotaSeasons.com.
Be sure to include a location.
 
   

 

   
           
 
MinnesotaSeasons.com Sightings
 
   

 

 

Binoculars


Last Updated:

About Us | Privacy Policy | Contact Us | © 2021 MinnesotaSeasons.com. All rights reserved.