oak rough bulletgall wasp

(Disholcaspis quercusmamma)

               
Conservation Status

IUCN Red List

not listed oak rough bulletgall wasp

NatureServe

not listed
Occurrence

Common

Flight/Season

One generation per year, late October to early November

Habitat

Anywhere host species are found

Size

Galls: 5 16 to in diameter


Identification

This cynipid gall wasp is usually identified by the gall it produces. In Minnesota, galls are found in clusters on the twigs and branches of bur oak and swamp white oak. They first appear as green bumps on the twig. The bumps later turn bright red. As they grow into round galls, they turn light brown and are soft. Eventually, they turn dark brown and harden. Mature galls are 5 16 to in diameter, woody, and spherical, with a nipple-like, obscure point at the top. They produce honeydew that attracts bees, and wasps, and ants, which protect the gall wasp from other parasitic wasps. Each gall contains only a single wasp, though they may be shared by other species (inquilines). A small, circular hole in the side of a gall indicates where the wasp has emerged.

The galls remain on the tree up to five years after the wasp has left the gall. They do not kill the host stem but will reduce the growth of the infested tree.

 
Similar
Species

 


Larval Hosts

bur oak (Quercus macrocarpa), swamp white oak (Quercus bicolor)

 
Adult Food

Adult wasps do not feed

 
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. Information is only available for the asexual generation. The sexual generation has not been described in entomological literature.

The female lays eggs in a dormant, terminal bud at the tip of a twig. In the late spring of the following year, the larva stimulates the growing stem to produce a gall in which the wasp develops. The larva pupates within a small cell in the center of the gall. In Minnesota, adults emerge in September. In the asexual generation, both winged and wingless females are produced. Males are unknown.

 
Behavior

 


Distribution Distribution Map  

Sources: 7, 30.


Comments

 


Taxonomy

Order:

Hymenoptera (ants, bees, wasps, and sawflies)

 

Suborder:

Apocrita (ants, bees, true wasps)

 

Infraorder:

Terebrantes

 

Superfamily:

Cynipoidea (gall wasps)

 

Family:

Cynipidae (gall wasps)

 

Subfamily:

Cynipinae

 

Tribe:

Cynipini

 
Synonyms

Disholcaspis mamma

 
Common
Names

oak rough bulletgall wasp


 

 

 

 

 

 

 

Glossary

inquiline

An animal that lives in the nest of an animal of another species.

       

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