Robin’s carpenterworm

(Prionoxystus robiniae)

Robin's carpenterworm
Photo by Bill Reynolds
  Hodges #

2693

 
 
Conservation Status
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

     
  Minnesota

not listed

     
           
 
Description
 
 

Robin’s carpenterworm is a medium-sized moth but a very large micromoth. It is similar in size and appearance to a sphinx moth and is often misidentified as one. Adults are 11 16 to 1¾ long with a wingspan of 17 16 to 3. The female is much larger than the male.

The body is heavy. The abdomen extends well beyond the hindwings.

The forewings on the female are more or less triangular and rounded at the tip. They are pale gray and semi-translucent with a dense, net-like overlay of thin, dark lines and, in the basal and median areas, wider lines that fill in the blank areas creating dark blotches. They have an accessory cell and 2 anal veins that are complete, extending from the base to the margin. Some of the veins branching off of the “R” vein are stalked. The forewings of the male are similar but narrower and more pointed at the tip. The hindwings of the female are as wide as the forewings but much shorter. They are similar in color to the forewings but with a less distinct overlay of thin lines and no wider lines. They have 3 anal veins. The hindwings of the male are similar in shape, black from the base to the median area, bright yellowish-orange from the median area to the submarginal area, and bordered with a thin black marginal line. The hindwings and forewings are held in contact by bristles (a frenulum) and scales (a retinaculum).

The head is gray. There are no mouth parts and no hearing organs. The antennae on the male are feathery, with extensions along both sides of the central axis (bipectinate). On the female the antennae are thread-like.

The legs are black with white bands. There is a large spine (spur) at the tip of the fourth leg segment (tibia).

The caterpillar is 2 to 2¾ long. It may be greenish-white with a dark brown head and thoracic shield, or pinkish with scattered dark spots and a reddish-brown head and thoracic shield.

 
     
 

Size

 
 

Wingspan: 17 16 to 3

Total Length: 11 16 to 1¾

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Deciduous and mixed forests, hardwood shelterbelts.

 
     
 
Biology
 
 

Season

 
 

May through July

 
     
 

Behavior

 
 

Adults are attracted to light.

 
     
 

Life Cycle

 
 

The female lays eggs singly or in groups in the crevices of the bark of a host tree. After hatching, the caterpillars feed by boring into the cambium layer of the tree. This creates galleries and tunnels under the outer bark that decrease the value of the wood and can sometimes kill the tree. Wood has little nutritional value. As a result, the caterpillar takes 3 or 4 years to complete its life cycle. It pupates in the spring of its final year and emerges as an adult between May and July.

 
     
 

Larva Hosts

 
 

Ash, black locust, oak, poplar, and willow

 
     
 

Adult Food

 
 

Adults do not feed

 
     
 
Distribution
 
 

Distribution Map

 

Sources

21, 24, 29, 75.

 
  12/18/2015      
         
 

Occurrence

 
 

Widespread but uncommon

 
         
 
Taxonomy
 
 

Order

Lepidoptera (butterflies and moths)  
 

Suborder

Glossata  
 

Infraorder

Neolepidoptera  
  Parvorder Heteroneura  
  No Rank Ditrysia  
  No Rank Apoditrysia  
 

Superfamily

Cossoidea  
 

Family

Cossidae  
 

Subfamily

Cossinae  
 

Genus

Prionoxystus  
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

carpenterworm

carpenterworm moth

locust borer

Robin’s carpenterworm

 
       

 

 

 

 

 

 

 

Glossary

frenulum

A spine (male) or multiple spines (female) at the base of the costal edge of the hindwing of many moths that couples with the retinaculum on the forewing to keep the wings in contact which each other.

 

Tibia

The fourth segment of an insect leg, after the femur and before the tarsus (foot).

 

 

 

 

 

       
Visitor Photos
   

Share your photo of this moth.

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

       
Bill Reynolds
       
  Robin’s carpenterworm   Robin’s carpenterworm
       
MinnesotaSeasons.com Photos
   
       
       
       

 

Camera

     
Slideshows
   
  Prionoxystus robiniae (Robin's Carpenterworm)
Allen Chartier
 
  Prionoxystus robiniae (Robin's Carpenterworm)  

 

slideshow

       
Visitor Videos
   

Share your video of this moth.

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

       
Bill Reynolds
       
  Robin's carpenterworm (Prionoxystus robiniae)
Published on Dec 18, 2015
 
   
 
About

The first two images, if you notice, the wings are blurred and the back end. It is vibrating it's muscle and getting ready for take off. The video is the … moth revving up.

Location: Pennington Co., MN

Video by Bill Reynolds

http://minnesotaseasons.com/Insects/Robins_carpenterworm.html

   
       
       
Other Videos
 
  Carpenterworm Moth (Cossidae: Prionoxystus robiniae) on Wall
Carl Barrentine
 
   
 
About

Uploaded on Jun 21, 2011

Photographed at Fisher, Minnesota (21 June 2011). Thank you to Maury Heiman (@Bugguide.net) for confirming the identity of this specimen!

   
       
  You're Just Too Good To Be True...Can't Take My Eyes Off You...
Carl Barrentine
 
   
 
About

Uploaded on Jun 24, 2011

A Crab Spider (Xysticus) sizes up a Carpenterworm Moth (Prionoxystus). ;-) Photographed at Grand Forks, North Dakota (24 June 2011).

   
       
  Robin's Carpenterworm Moth (Cossidae: Perionoxystus robiniae) Lateral View
Carl Barrentine
 
   
 
About

Published on Jun 2, 2012

Photographed at Grand Forks, North Dakota (02 June 2012).

   
       
  Carpenter Moth (Cossidae: Prionoxstus)
Carl Barrentine
 
   
 
About

Uploaded on Jun 7, 2010

Photographed at Grand Forks, North Dakota (06 June 2010).

   
       

 

Camcorder

         
Visitor Sightings
   

Report a sighting of this moth.

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

Bill Reynolds
6/22/2015

Location: Pennington Co

… the wings are blurred [on] the back end. It is vibrating it's muscle and getting ready for take off.

Robin’s carpenterworm


     
     
 
MinnesotaSeasons.com Sightings
         

 

 

 

Binoculars


Last Updated:

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