Disholcaspis globosa (agamic)

D globosa is typically mistaken for its far more apparent cousin D q globulus, also found on Quercus alba. The most reliable way to distinguish them is by location. Weld lists D globosa as a "root" gall, and it is typically found in clusters where young trees meet the surface of soil, often concealed by leaf litter. However, D globosa is apparently found on nodes or along the stems of young sprouts and occasionally at the base of lateral branches of mature trees as well, where it might be confused with D q globulus. Aside from its location, it can be distinguished by its deep red color (though both species are yellow/pink when immature) and more haphazard distribution around stem nodes in larger numbers than is typical for D q globulus. D globosa also seems to be more velvety in texture and lack the raised points/splits of D q globulus. Some galls may not be definitively identifiable as one or the other without rearing adult wasps.

Disholcaspis globosa, new species

Hosts: Quercus alba

Similar to those of Disholcaspis globulus (Fitch) in appearance, but less regular in shape and dark red or sometimes yellowish. They occur in clusters at base of 2-3 year old sprouts from stumps and are almost always hidden by debris. Scattering small ones are sometimes seen exposed a few inches above the surface. They are closely crowded together about the base of sprouts and there may be from two or three to as many as forty in the cluster. Each is 8-12 mm in diameter, the interior spongy, with a distinct thin inner shell.

Type locality. — Fort Sheridan, Illinois. The writer has also collected these galls at Highland Park, Ravinia, Evanston, Glen Ellyn, and New Lenox, Illinois; at Ithaca, New York; and at Tuskahoma, Oklahoma. About Chicago the galls have been found containing pupae on September 12, and with adults October 3. Adults emerge in the late October and early November. At Ithaca pupae were found as early as September 1. The American Museum of Natural History has galls from Bartow, New York, collected by E. B. Southwick.

Note. — Similar galls were collected on Quercus prinus Linnaeus at East Falls Church, Virginia, August 31, 1919, and contained pupae September 13.

Disholcaspis globosa (agamic)

Image Details

Further Information (4)

Disholcaspis globosa (agamic) agamic: The agamic (AKA unisexual) generation of an oak gall wasp (cynipini) species consists of only female wasps, which do not mate before laying the eggs which become the male and females of the sexual generation (sexgen). View in glossary →

Further Information (4)

Disholcaspis globosa (agamic)