spongy oak apple gall wasp

(Amphibolips confluenta)

Conservation Status
spongy oak apple gall wasp
  IUCN Red List

not listed

     
  NatureServe

not listed

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Spongy oak apple gall wasp is usually identified by the galls it produces. The galls appear on growing leaves in the spring or early summer. When they first appear the galls are green, round, and small. As the larva grows the gall grows to 1¼ to 2 in diameter and may take over most or all of the leaf. Late in the season it turns light brown and feels spongy when lightly squeezed.

 
     
 

Size

 
 

Gall: 1¼ to 2 in diameter

 
     
 

Similar Species

 
 

Acorn plum gall wasp (Amphibolips quercusjuglans) produces galls on the side of acorns.

Gouty oak gall wasp (Callirhytis quercus punctata) produces galls on twigs, not leaves.

Larger empty oak apple wasp (Amphibolips quercusinanis) galls are spotted. When the gall is dry the spots become slightly protruding bumps.

Oak gall wasp (Amphibolips cookii) galls are much smaller, no more than 1 in diameter, and are spotted. They protrude from a leaf bud, not a developing leaf.

Translucent oak gall wasp (Amphibolips nubilipennis) produces a soft, ½ to ¾, almost translucent gall that resembles a white grape.

 
     
 
Habitat
 
 

 

 
     
 
Biology
 
 

Season

 
 

Winged adults: Fall

 
     
 

Behavior

 
 

 

 
     
 

Life Cycle

 
 

The life cycle of this wasp involves alternation of generations, one generation with only asexual females and one generation with both sexual males and sexual females.

After mating in the fall the sexual female wasp drops to the ground. She burrows into the soil at the base of a host tree and injects her eggs into the tree’s roots. These eggs, the first generation embryo stage, overwinter. When they hatch in the early spring, the larvae begin feeding on the roots. Soon they enter the pupal stage, a period of inactivity and metamorphosis. Later, still in the spring, the wingless, asexual female adult hatches and emerges from the soil. She crawls up the tree trunk, finds a leaf, and injects a single egg into the midrib. She then finds another leaf and repeats the process with her remaining eggs. These eggs are the second generation embryo stage. The egg hatches and the larva begins feeding on the leaf. This causes a chemical reaction in the leaf that results in the formation of a ball-like gall. The galls appear in the late spring or early summer. As the season progresses the larva gets larger and so does the gall. Second-generation, winged, male and female sexual adults emerge in the fall and immediately search out a mate. The cycle continues.

 
     
 

Larva Hosts

 
 

Some of the red oaks (Quercus section Lobatae), including northern red oak (Quercus rubra), northern pin oak (Quercus ellipsoidalis), and black oak (Quercus velutina).

 
     
 

Adult Food

 
 

Adult wasps do not feed.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

7, 24, 30.

 
  1/16/2020      
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
 

Order

Hymenoptera (ants, bees, wasps, and sawflies)  
 

Suborder

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

Superfamily

Cynipoidea (gall wasps)  
 

Family

Cynipidae (gall wasps)  
 

Subfamily

Cynipinae  
  Tribe Cynipini (oak gall wasps)  
 

Genus

Amphibolips  
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

large oak apple gall wasp

oak apple gall wasp

oak-apple gall

spongy oak apple 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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Luciearl

 
    spongy oak apple gall wasp      
           
  Not sure if there is a category for these, but neat to find them still on the tree. I have only found the Acorn Plum Galls on the ground in the past   spongy oak apple gall wasp  
 

Joe Fulton

 
  4 found on Iron wood from last year   spongy oak apple gall wasp  
           
 
MinnesotaSeasons.com Photos
 
    spongy oak apple gall wasp   spongy oak apple gall wasp  
           
    spongy oak apple gall wasp   spongy oak apple gall wasp  
           

 

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Visitor Sightings
 
           
 

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  Luciearl
1/14/2020

Location: Cass County

spongy oak apple gall wasp  
  Luciearl
8/11/2018

Location: Fairview Township

Not sure if there is a category for these, but neat to find them still on the tree. I have only found the Acorn Plum Galls on the ground in the past

spongy oak apple gall wasp  
  Oak Gull
6/16/2017

Location: carver Mn

shit  ton on my backyard oak tree

   
  Joe Fulton
4/14/2016

Location: Pequot Lakes

4 found on Iron wood from last year

spongy oak apple gall wasp  
  Brian Fanger
6/22/2014

Location: Andover Minnesota

20 on 1 branch

   
           
 
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