Andricus operator

Callirhytis operator

Andricus operatola

Callirhytis operatola

Cynips quercus operatola

Callirhytis quercusoperatola

Cynipidae

Callirhytis

Quercus buckleyi

Kansas

Oklahoma

Texas

Quercus coccinea

Alabama

Arkansas

Connecticut

Delaware

Georgia

Illinois

Indiana

Kentucky

Louisiana

Maine

Maryland

Massachusetts

Michigan

Mississippi

Missouri

New Hampshire

New Jersey

New York

North Carolina

Ohio

Pennsylvania

Rhode Island

South Carolina

Tennessee

Vermont

Virginia

West Virginia

Wisconsin

Quercus falcata

Florida

Quercus ilicifolia

Ontario

Quercus imbricaria

Iowa

Quercus incana

Quercus laurifolia

Quercus marilandica

Nebraska

Quercus myrtifolia

Quercus palustris

Quercus phellos

Quercus rubra

Minnesota

New Brunswick

Nova Scotia

Prince Edward Island

Quebec

Quercus velutina

Cynipid galls of the eastern United States

Life histories of American Cynipidae

The North American acorn galls with descriptions of new species

Callirhytis quercusoperator (agamic)

Andricus operatola

Forms a flattened tooth-like or wedge shaped gall on the outside between the cup and the acorn with the ends more or less protruding. It lies in a depression and is of a light brown color. Often there are as many as eight galls on a single acorn. It occurs on red, scarlet, black and scrub oak. According to H. F. Bassett the galls mature in autumn, and early in the spring following part becomes imagos, another part remaining in the larval state another year, while a few remain in this condition still longer, and, as suggested by C. V. Riley, may develop the third year. 

Habitat: Ottawa, Can., Conn., N. Y., N. J., Penn., and westward. 

Andricus operator form operatola

Cynips quercus operatola
Callirhytis operatola
Andricus operatola
Callirhytis operator
Andricus operator

Gall. — A small, seed-like gall (Figs. 30 and 31) at the base of the nut of the acorn, inside the cup. The gall suggests a development of the aborted ovule of the acorn, but sometimes five or six occur in a single acorn. It is a compressed, inverted cone in shape, about 5 mm. high by 4 mm. in diameter, larger or smaller, and is thin-walled, the larval cell occupying most of the gall. In the acorns of Quercus ilicifolia and of the other red oaks on which the bisexual form occurs. 

Range: Ontario, MA, RI, CT, NY, NJ, PA, DC, IL, New Brunswick

The most remarkable character of the heterogeny of this species really lies in the very great differences of the galls of the two generations, and even this does not appear so remarkable when one considers the totally different natures of the parts of the plant affected. 

The gall of operatola usually escapes detection until the fall, when the growing gall projects beyond the rim of the acorn cup and often splits or otherwise deforms the nut of the acorn. These galls fall to the ground, sometimes fixed in place, more often broken out of the fruit, so that acorns bearing the scars of the galls may be found abundantly under scrub-oaks. The galls are highly parasitized and are often much damaged by wintering on the ground — another instance of the poor quality of the “protection” afforded a gall-wasp. Consequently, it is a difficult matter to rear the adults of this form. Bassett states that the insects may mature the following spring or may remain in the galls until the second or even third spring before they emerge. He found them emerg- ing May 4 and ovipositing in the young buds of the oaks. 

Bassett’s observations of this species finally led to the first absolute proof that heterogeny occurred in the Cynipidae. A detailed account of the discovery has been given on page 324. Adults have been bred from galls of both generations and each of these have been observed to oviposit to produce the galls of the other generation. Bassett’s observations were apparently made in the open, but his definite statements would indicate that the pricked parts were definitely marked for later identification. 

Andricus operator

Hosts: Quercus marilandica, coccinea, ilicifolia, velutina, schneckii [shumardii]

GALL. — An oval larval cell, mostly inseparable from and occupying most of a thin-walled, seed-like capsule. These capsules woolly, clustered in the bisexual generation, naked in the agamic generation, producing the following forms of galls; on eastern American black oaks. 

Agamic Generation : The larval cell occupying most of a triangulate or obconical capsule, somewhat compressed, up to 5. by 4. mm. in dimensions, one to six, usually one, between the nut and the cup of the acorn; on all of the black oaks which bear the bisexual generation. 

RANGE. — Ottawa to Virginia, Texas, and Illinois. Probably thruout more eastern North America wherever black oaks occur. 

[Kinsey goes on to describe several varieties that differ by host, range, and gall morphology; see paper for details]

Studies of some new and described Cynipidae (Hymenoptera)

Callirhytis operator OS
Agamic form, operatola Bass.

Gall, seed-like galls at base of nut, inside cup.

Adults, May.

On Q rubra, coccinea, nigra, and ilicifolia

Plant Galls and Gall Makers

Callirhytis operator agamic

Quercus coccinea, ilicifolia, imbricaria, rubra, texana [buckleyi], velutina
Acorn galls
A pip gall beside mature acorns in the fall, dropping out in Sept.

[Photo caption]
Fig 65 On Q rubra. Also on Q velutina, coccinea, imbricaria, ilicifolia. The original material of this species was collected at Waterbury CT Aug 23, 1871 on Q ilicifolia during Riley's visit to Bassett. Bassett kept his galls a year and rearing nothing threw them away. Riley kept his longer and the second spring appeared the maker "just as the oak buds were bursting." His label bears the date Apr 5 1873. This established an alternation of generations in the cynipidae.

Fig 66 Female of Callirhytis operator sex.gen. ovipositing in the one-year old acorn of Q velutina on June 26 (IL) to produce the pip gall of Fig 65.

"Like Callirhytis operator agamic"

Quercus cinerea [incana], falcata, marilandica, myrtifolia, phellos
Acorn galls
Pip gall like Callirhytis operator agamic. Fig 65 beside mature acorn in the fall. Never reared.

Callirhytis quercusoperator (Osten Sacken 1861)

Hosts: Quercus inopina, myrtifolia

[Asexual generation acorn gall found in Florida in the fall.]

Using gall wasps on oaks to test broad ecological concepts

Galls of this generation are often overlooked because they are minimally visible beneath the acorn cup. Removing the cups of acorns in the fall may reveal a much higher abundance of this gall than otherwise apparent. 

Gallformers ID Notes