spiny rose stem gall wasp

(Diplolepis spinosa)

               
Conservation Status

IUCN Red List

not listed spiny rose stem gall wasp

NatureServe

not listed
Occurrence

Common

Flight/Season

One generation per year

Habitat

Prairies on Wood’s rose and woodlands on smooth rose

Size

Gall: about in diameter

Adult: to ¼ long


Identification

This cynipid gall wasp is usually identified by the gall it produces. The gall is spherical or irregularly spherical and about in diameter, about the size of a golf ball. When found in prairies on Wood’s rose, they are weakly spined or have no spines at all. When found in woodlands on smooth rose they are densely covered with spines. When young they are green and the spines are soft. When mature they are reddish-brown or purple, hard, and woody. The gall is firmly attached to the plant and cannot be removed without snips.

Adults are to ¼ long. The males are black, the females are reddish-brown. The front segment (mesosoma) is short and strongly arched, giving a hunchback appearance.

 
Similar
Species

 


Larval Hosts

Smooth rose (Rosa blanda var. blanda), Wood’s rose (Rosa woodsii var. woodsii), and rugose rose (Rosa rugosa) cultivars.

 
Adult Food

Adults do not feed.

 
Life Cycle

In the spring the female deposits up to 16 or more eggs in a leaf bud at the base of the apical meristem. The eggs hatch after 10 to 15 days and the larvae begin feeding on stem tissue. The plant responds by producing a thick layer of stem cells around the larvae. The gall is first noticeable when it is about twice as wide as the shoot. At this phase each larva is small and eats little.

In mid-June the larva enters the maturation phase and grows rapidly, consuming all of the nutritive cells in its chamber. The gall reaches its maximum size in late June.

In mid-August the larva stops eating and enters a pre-pupa stage. It overwinters in this stage. The gall is often above the level of the snow and the insect inside is subjected to extremes of temperature. It avoids freezing by producing and accumulating glycerol.

In early spring the insect enters the white pupa stage. When the temperature reaches 54° the pupa darkens. In the spring or summer, when the buds of the host plant are growing, the adult chews an exit tunnel from its chamber and flies off in search of a mate.

The adult lives just 5 to 12 days.

 
Behavior

 


Distribution Distribution Map  

Sources: 7.


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:

Diplolepidini

 
Synonyms

Diplolepis multispinosus

Rhodites multispinosus

 
Common
Names

spiny rose stem gall wasp


 

 

 

 

 

 

 

Glossary

apical meristem

Embryonic tissue at the tip of a root or the bud of a stem where cell division occurs causing growth in length.

 

mesosoma

In Hymenoptera: the front part of the body, consisting of all three segments of the thorax and the first segment of the abdomen, to which the wings are attached.

       

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Raevensong
8/15/2017

Location: Pennington County, MN


     
     
 

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