Diplolepis radicum

Family: Cynipidae | Genus: Diplolepis
Detachable: integral
Color: red
Texture: bumpy
Abundance:
Shape:
Season: Spring, Summer
Related:
Alignment:
Walls:
Location: underground (roots+), stem
Form:
Cells: polythalamous
Possible Range:i
Common Name(s): Rose Root Gall Wasp
Synonymy:
Pending...
Slide 1 of 2
image of Diplolepis radicum
image of Diplolepis radicum
image of Diplolepis radicum
image of Diplolepis radicum
image of Diplolepis radicum
image of Diplolepis radicum

Galls induced by cynipid wasps of the genus Diplolepis (Hymenoptera: Cynipidae) on the roses of Canada's grasslands

Diplolepis radicum (Osten Sacken)

Diplolepis radicum was described from galls in the central United States (Osten Sacken 1863). Adult females are among the largest of the genus, averaging 3.0–4.0 mm in length. Kinsey (1922) and Shorthouse (1988) provided additional information on the adults.

Galls of D. radicum are by far the largest of all Diplolepis galls, ranging in size from 2.5 to 6.0 cm, with some 10 cm in diameter. They are found throughout the grasslands of the prairies and in southern British Columbia. However, they are difficult to locate, especially when partially buried in the ground or hidden by vegetation. They are formed at the tips of adventitious shoots (Fig. 1) just below the surface of the ground. Although galls of this species are commonly referred to as root galls because of their location, they are stem galls (Fig. 42).

Females crawl down cracks in the ground at the base of roses in early spring to locate adventitious shoots before they protrude above the surface. Large numbers of eggs, sometimes numbering 200–350, are laid within the shoot tips and the resulting larvae produce irregularly rounded, tomato-shaped, multi-chambered galls (Fig. 43) of variable size. Galls are soft and succulent when growing, with the larval chambers packed throughout the mass of the gall (Fig. 43). They always have a smooth surface and are reddish-brown throughout all stages of development.

Diplolepis radicum appears to be as widely distributed as D. spinosa. Diplolepis radicum has been recorded from Ontario to North Carolina on R. carolina and west to Colorado and north to Oregon and Washington State on R. nutkana and R. woodsii (Beutenmüller 1907, 1914; Weld 1926). Galls are found on R. woodsii across the prairies and appear to be most abundant where the soils are sandy. Galls are found on R. woodsii in southern British Columbia.

Less is known about the community of inhabitants associated with this gall than about those of other species. For inhabitants of 40 galls collected in the fall from the Great Sand Hills of Saskatchewan, 27.2% were inducers, 2.9% were Periclistus sp., and the rest were parasitoids. Eurytoma sp. and Pteromalus sp. were the most abundant parasitoids.

- Joseph Shorthouse, KD Floate: (2010) Galls induced by cynipid wasps of the genus Diplolepis (Hymenoptera: Cynipidae) on the roses of Canada's grasslands©


Further Information:
Pending...

See Also:
iNaturalist logo
BugGuide logo
Google Scholar logo
Biodiversity Heritage Library logo