Cecidomyiidae

Asteromyia

Baccharis angustifolia

Alabama

Florida

Georgia

Louisiana

Mississippi

North Carolina

South Carolina

Gutierrezia californica

California

Gutierrezia microcephala

Arizona

Colorado

Nevada

New Mexico

Texas

Utah

Gutierrezia sarothrae

Idaho

Kansas

Minnesota

Montana

Nebraska

New York

North Dakota

Oklahoma

Oregon

South Dakota

Washington

Wyoming

Alberta

Manitoba

Saskatchewan

Gymnosperma glutinosum

Medranoa palmeri

Asteromyia gutierreziae

Asteromyia gutierreziae new species

The midges described below were reared by Mr. P. H. Timber- lake in May and June, 1914, from a black, blister-like gall on the slender flower stems of Gutierrezia sarothrae, collected near Salt Lake City, Utah. 
Gall. — Irregular, dull black thickenings of the slender flower stems, ranging in length from 6 to 8 mm. and approximately doubling the thickness of stems, with a diameter of .5 mm. Except for its location the deformation is very similar to that of C. carbonifera.



New Western Gall Midges

Little known midge galls of certain composites

 - [on *Baccharis*]: black, 3-4 mm diam.
 - [on *Gutierrezia*]: on stems, black; cylindrical, continuous around stem; about 2-3 times diameter of stem, 5-9 mm long. One larva/gall.
 - [on *Gymnosperma*]: on stems as for *Gutierrezia*. On leaves, they are elliptical; black; 3-5 mm diam.
 - [on *Isocoma [Medranoa]*]: on stems as for *G. microcephala* but smaller, 5-6 mm long.
...
[He lists the following host records for this species, verified by both host and insect identification: *Gutierrezia microcephala*, *Gutierrezia sarothrae*, *Gymnosperma glutinosum*, *Isocoma palmeri [Medranoa palmeri]*.]
...
[Additionally, he lists the following as possible *Asteromyia* hosts based on observations of galls only (no insect material available):]

Following are species on which I have collected galls, presumably of *Asteromyia*, but from which no larvae, pupae, or adults were available for study....
...
*Baccharis halimifolia* L.—Md., Fla.
*B. bigelovii* Gray—Ariz.
*B. douglasii* DC.—Calif.

A Taxonomic Revision of the Genus Asteromyia (Diptera: Cecidomyiidae)

Asteromyia sp. near gutierreziae Felt

Host: Baccharis angustifolia

Black, circular leaf blister

Galls become hard with age. Only the larva of this species is known. It is probably multivoltine. 

Distr: TX

The plant-feeding gall midges of North America

Gagne (1968) considered a larval specimen from Baccharis in Texas to be Asteromyia gutierreziae because it was similar to larvae of that species. Two other kinds of larvae based on differences in the spatulae (Figs. 14-16) have since been found. With- out pupae and adults, nothing more can be done to identify these. Because the spatulae are so different, the larvae are placed here as Asteromyia sp. 1, sp. 2, and sp. 3.

Asteromyia sp. 1, near gutiereziae Felt

This segregate is known from a single larva with a three toothed spatula (Fig. 14) similar to that found in A. gutierreziae. It was placed under A. gutierreziae in Gagne (1968). The specimen was taken from a blister leaf gall on Baccharis angustifolia (probably =salicina) collected in Kenedy Co., Texas, 20-XII-1940 by R. Runyon and found in the botanical collections of the USNM. 

Asteromyia sp. 2 

The larval spatula (Fig. 15) of this seg- regate has many fine serrations along the anterior edge. It is known from two speci- mens from Texas, each from a different spe- cies of Baccharis: B. pteronioides, Frijole Ranch, Guadalupe Mountains National Park, Culberson Co., Texas, X- 16- 1990, P. E. Boldt; and B. higelovii. Point of Rocks, 12 mi. W Ft. Davis, Jeff Davis Co., Texas, VI- 12- 1990, P E. Boldt. 

Asteromyia sp. 3

The larval spatula of this segregate has a smooth anterior edge (Fig. 16). The single known larva was taken from a blister gall of B. salicina, Greenbelt Reservoir, 4 mi. N Clarendon, Donley Co., Texas, X-5-1988, P E. Boldt and T O. Robbins.

The Gall Midges (Diptera: Cecidomyiidae) of Baccharis spp. (Asteraceae) in the United States

Asteromyia gutierreziae
Black-Stem-Gall Midge
[Page 248]

This midge initiates monothalamous, slightly swollen stem galls on desert broom [Baccharis sarothroides], match-weed [Gutierrezia microcephala], and broom snakeweed [Gutierrezia sarothrae].

[Range: Mojave Desert, CA; Escalante Desert, UT; NM]

Plant Galls of the Western United States

Gagné (1968) noted that the *Baccharis*-reared record, which included only one larva, could be distinguished morphologically from typical *A. gutierreziae* larvae in one detail: larger, toothed verrucae, but concluded that one difference was not enough to establish it as a distinct species. 

However, *Baccharis* is now thought to be rather distantly-related to the other *A. gutierreziae* hosts. According to Guy Nesom's latest taxonomic summary (2020), *Baccharis* is in the subtribe Baccharidinae, while the rest of the hosts are in Gutierreziinae. A clade containing both subtribes would also have to include most of the rest of the North American Astereae genera (e.g. *Solidago*, *Symphyotrichum*, *Pentachaeta*, *Doellingeria*, *Erigeron*, etc.). Gall-formers' host ranges do not have to perfectly recapitulate host phylogenies, of course, but this does suggest that the *Baccharis* record may be truly distinct.

For now, we've tentatively included all *Baccharis* records for *Asteromyia* galls under *A. gutierreziae*, but with the understanding that they may actually represent an undescribed species.

Gallformers ID Notes