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76
Journal of the Lepidopterists' Society
GENERAL NOTES
OCCURRENCE OF SPEYERIA ID ALIA (NYMPHALIDAE) ON REMNANT PRAIRIE IN NORTHWEST WISCONSIN
Although intensely local and restricted to areas of virgin prairie, Speyeria idalia (Drury) is widely distributed over the north central United States. Surprisingly, there have been no records for northwest Wisconsin (Ebner 1970, Milwaukee Public Mus. Popular Sci. Hbk. 12; Masters 1973, J. Res. Lep. 11: 175-182) although the original vegetation of Wisconsin included prairie areas extending as far northwest as St. Croix, Polk and southern Burnett counties. During the summer of 1972, I located small remnant stands of virgin prairie in St. Croix, Polk, Eau Claire, Chippewa and Dunn counties and discovered that small populations of S. idalia occurred on many of them. Prairie areas were located by carefully searching railway right of ways (many railways were built in this area before it was heavily settled), cemeteries, and in areas of shallow, rocky soil where agriculture has never been attempted. The localities surveyed are:
Polk County. Very nice stands of dry (xeric) prairie are found on exposed hilltops in the Interstate State Park. These prairie areas are relatively inaccessible and are virtually undisturbed. They are excellent areas to study xeric prairie flowers. Although I spent quite a bit of time here, S. idalia was not observed. It is quite possible that the area is too dry and it never occurred here. I was unable to locate any additional prairie stands in Polk County through searching railway right of ways and cemeteries.
St. Croix County. Several small stands of virgin prairie were located along railway right of ways in St. Croix County. Although they were all of small size and somewhat disturbed, a small population of S. idalia, often just one example, was found on each of them. Specific localities as follows:
Hudson Twp. (T 29 N—R 19 W): SESE sec. 17, a very small population on about xk acre of prairie along railway right of way; SESE sec. 13, one specimen taken along traces of remnant prairie along railway. Warren Twp. (T 29 N—R 18 W): SENW sec. 19, a small population of 15 acres of land belonging to the C. St. P. M. & O. Railroad. Richmond Twp. (T 30 N—R 18 W): NWNE sec. 10, one specimen taken on prairie bordering railway; NESW sec. 16, a sight record along railway.
Remnant Oak Openings, which are closely related to prairies with many flowers in common, were found in the Willow River State Park, however, S. idalia was not observed here.
Dunn County. The tracks of the C. & N. W. Railroad run parallel to highway 12 across Dunn County. I carefully traced this entire route and, although I did find a few very small patches of prairie, I did not observe Speyeria idalia.
Eau Claire County. Quite a bit of collecting was done in Pine Barren areas of Seymour Twp. (T 27 N—R 8 W). The Pine Barrens have many plant species in common with the prairies and there is even some degree of intergradation between Pine Barren and Xeric Prairie. In fact, this is the only location in Wisconsin where I have actually found the assumed foodplant for S. idalia, the Birdfoot Violet (Viola pedata). I did not take or observe S. idalia in Eau Claire County, however Fay Karpuleon of Eau Claire, reports having taken one specimen in the Pine Barrens on 15 July 1972.
Chippewa County. There are small patches of virgin prairie in fairly good condition all along the C. & N. W. Railroad tracks between Eau Claire and Chippewa
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Falls. I collected one male of S. idalia on a 10 acre patch in Hallie Twp. (T 28 N— R 9 W): SWSE sec. 13. No further attempts were made to locate the species in Chippewa County.
Conclusions
Speyeria idalia is established and apparently able to maintain itself in very small populations on small (in some cases as little as % acre) remnant prairie in northwest Wisconsin. All of the ascertained localities were along railroad right of ways, which casts some doubt upon their future. In recent years the railroads have shown an increasing tendency to sell off excess land and to use herbicides for weed control along right of ways instead of burning as they have done in the past. These practices may very well result in the final demise of this type of remnant prairie.
John H. Masters, 5211 Southern Avenue, South Gate, California 90280.
THE "GREASY" WING GENE OF UTETHEISA ORNATRIX (ARCTIIDAE)
The genus Utetheisa Hiibner is represented by Utetheisa bella Linne and Utetheisa ornatrix Linne which are normally allopatric in the New World. U. bella is common in the southern U.S.A., migrating northward each season to feed on Crotalaria. Isolated seasonal populations in the north can produce huge multi-brooded local populations, demonstrating the genetic diversity of the genome of the original migrants. Remington (1956, Proc. 10th Internat. Cong. Ent. 2: 797-803) and Pease (1968, Evolution 22: 719-736) determined the genetic background of the principal morphological characters of the genus, noting the character differences and their frequencies within the five subspecies of the Utetheisa ornatrix group.
The author's collection contains 837 specimens of U. bella taken at an isolated locality five miles north of Liverpool, Pennsylvania, over a period of five weeks in 1969. This sample contains all of the subspecies phenotypes described by Pease. A similar sample of 60 specimens was taken at the same location during a three-week period in 1973 with the same phenotypic frequencies observed in 1969. These samples show no character that would indicate the intrusion of U, ornatrix genome in these migrants. The white ground color of the forewing for example, is uniform throughout.
U. ornatrix is rare in the United States but is common throughout Mexico and Central America wherever its food plant, Crotalaria, is growing. Unlike U. bella, which is highly variable, U. ornatrix is constant in its pattern. The forewings are white, except for a red costal line broken by black dots; three marginal rows of black-red-black dots extend from the costal markings in varying degrees of intensity. The hindwings are white with wide black margins. Thus mass samples appear to be quite uniform, except for an occasional red blotching or streaking on the forewing.
Areas of sympatry of U. bella and U. ornatrix provide an interesting array of patterns on the interspecific hybrids. Such a hybrid population exists in southern Florida.
The analysis of a large sample composed of 81 males and 31 females of U. ornatrix taken 10 August 1972 at Oxchuc, Chiapas, Mexico revealed the presence of a new character designated as "greasy" which gives the usually immaculate white forewing so common in this species a dull vitreous grey color. Other characters were those usually associated with U. ornatrix; all had white hindwings, all had pale forewing dorsal discs (two males with red blotching), and all but one male and one female had unspotted forewing dorsal discs. In addition, all had wide hind wing black margins.