spiny rose gall wasp

(Diplolepis bicolor)

Conservation Status
spiny rose gall wasp
Photo by Twogalls
  IUCN Red List

not listed

 
  NatureServe

not listed

 
  Minnesota

not listed

 
           
           
           
           
           
           
           
 
Description
 
 

Spiny rose gall wasp is a relatively tiny cypnid wasp that creates a relatively large gall. It occurs in only North America: in the east from Ontario to North Carolina west to Minnesota and Missouri; and in the west from British Columbia and Alberta south to California. It is also found in Nova Scotia but not in Newfoundland.

The adult is very small and inconspicuous. The body is short, to ¼ (3 to 6 mm) long, and somewhat globe-shaped. It is difficult to see and virtually impossible to identify in the field. However, it is easily identified by the abnormal plant growth (gall) it produces.

In the spring a gall appears on a leaflet of a prairie rose or Wood’s rose. It is fully formed and succulent by the end of June and turns brown in July. It has a single chamber with one larva. It has thick walls and is covered with spines. The spines are long, up to as long as the gall is wide. Mature galls are ¼ to 716 (7 to 11 mm) in diameter. A large gall will completely obliterate the leaflet.

 
     
 

Size

 
 

Total length: to ¼ (3 to 6 mm)

 
     
 

Similar Species

 
 

Spiny rose stem gall wasp (Diplolepis spinosa) galls are produced on host plant stems, not leaves. The galls are much larger and the spines are much shorter.

 
     
 
Habitat
 
 

 

 
     
 
Biology
 
 

Season

 
 

Late May

 
     
 

Behavior

 
 

 

 
     
 

Life Cycle

 
 

The larva spends the summer, pupates, and overwinters inside the gall. In late May the following year the adult chews a hold in the gall and emerges. The adult stage lasts only 5 to 12 days.

 
     
 

Larva Hosts

 
 

Prairie rose and Wood’s rose

 
     
 

Adult Food

 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 27, 29, 30, 82, 83.

 
  6/29/2023      
         
 

Occurrence

 
 

Widely scattered

 
         
 
Taxonomy
 
 

Order

Hymenoptera (ants, bees, wasps, and sawflies)  
 

Suborder

Apocrita (narrow-waisted wasps, ants, and bees)  
  Infraorder Proctotrupomorpha  
 

Superfamily

Cynipoidea (gall wasps and allies)  
 

Family

Cynipidae (gall wasps)  
 

Subfamily

Cynipinae  
  Tribe Diplolepidini (rose gall wasps)  
 

Genus

Diplolepis  
       
 

Synonyms

 
 

Cynips bicolor

 
       
 

Common Names

 
 

spiny rose gall wasp

 

 

 

 

 

 

 

 

 

Glossary

Gall

An abnormal growth on a plant produced in response to an insect larva, mite, bacteria, or fungus.

 

 

 

 

 

 
 
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Twogalls

 
  Found these 2 galls on a John Cabot climbing rose we planted 3 years ago. We've never seen them before.   spiny rose gall wasp  
           
 
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  Loretta Fogg
6/28/2023

Location: Fairbanks, Alaska

Little hanging spiky orbs (galls?) which look totally out of place.  I'm seeing them all over our wild roses. 

 
  Jan Bielat
7/2/2020

Location: Sartell in Stearns County, MN

Found these 2 galls on a John Cabot climbing rose we planted 3 years ago. We've never seen them before.

spiny rose gall wasp  
           
 
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Created: 7/18/2020

Last Updated:

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