246 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY

URBANUS DORANTES DORANTES STOLL (HESPERIIDAE):

ANOTHER EXAMPLE OF FLORIDA'S

POPULATION EXPLOSION

EDWARD C. KNUDSON

Department of Radiology, Baylor College of Medicine, Texas Medical Center, Houston, Texas 77025

One hears so much about the population explosion in Florida, that it seems difficult to imagine at times how even a butterlly could survive it. Indeed, the drainage of the swamps, burning and bulldozing of forest lands, and increasing levels of pollution have gravely endangered many of Florida's unique species of Lepidoptera. In spite of this, certain other species are experiencing a 'population explosion' of their own.

One such species is Urbanus dorantes dorantes Stoll, which, prior to 1969, was not believed to be present in Florida. Kimball (1965) listed an old record from the Cleveland Museum, labeled Tampa, 1908, and Miami, 1916, but this was thought to be fraudulent. However, Clench ( 1970) discovered that the species was common at Chokoloskee (Collier County) on 20 November 1969. During March and April 1970, Miller & Miller (1970) took specimens at Homestead (Dade County), Key Largo, and Tavernier (Monroe County). Pliske (1971) reported that U. dorantes dOl'antes was common in Dade County from November 1969 through January 1970. Also, C. Hallas has reported specimens from Dadc County in April and December 1971, and from Key Largo in January 1972. In addition, Burris (1973) took specimens in Hillsborough County during February and April 1972.

The first specimen of U. dorantes dorantes taken by the author was found in Pahokee (Palm Beach County) on 12 June 1971. Then, on 12 October 1972, dorantes was found to be common near Bartow (Polk County). A more careful search of more northerly areas revealed this hesperiid to be present in Gainesville (Alachua County) as well. Urbanus proteus L. was abundant at the time and it was estimated that U. dorantes dorantes comprised at least five percent of the tailed skippers seen in the Gainesville area. On 16 October 1972 several specimens were taken in Yulee (Nassau County) at blossoms of iron­weed and Trilisa sp. along the roadside.

On 4 November 1972 U. dorantes dorantes was found to be common at Lake Worth (Palm Beach County), Homestead, and Key Largo. In these localities it was clearly the dominant tailed skipper. On Key

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Largo a half acre field, overgrown with Lantana sp. and Bidens pilosa L., was estimated to contain about one hundred specimens of dorantes and only a few of proteus. The flight pattern of the two seemed to be quite similar, although dorantes was somewhat faster and less erratic than proteus. The absence of green iridescence in dorantes was not easily evident while on the wing, and the two species were best distin­guished in the field by the difference in maculation of the underside of the hindwing. On upper Key Largo, U. dorantes dorantes could also be found along the roadside and on shaded trails through the tropical hardwood forest. Along the forest trails it was observed that the flight pattern of dorantes was remarkably similar to that of Polygonus leo ( Gmelin), i.e., dorantes would dart back and forth between the dense vegetation on either side of the trail and finally alight on the under­side of a leaf.

U. dorantes dorantes was again observed in the same localities in southern Florida during late November through December 1972, and on 18 December 1972 it was captured in Largo and Dunedin (Pinellas County). Subsequently the populations declined, although on 6 March 1973 dorantes was still present on Key Largo and was also found at Devils Gardens (Hendry County).

During October, November, and December 1972, a careful search was made for the larvae of U. dorantes dorantes on leguminous plants at various locations. These plants were: at Bartow, Pueraria thun­bergiana (S. & Z.); at Lake Worth, Vigna marina Merrill; at Homestead, Glycine max L. and Phaseolus lathyroides L.; and at Key Largo, Galactia spiciformis Torr & Gray and Desmodium tortuosum DC. The plants were checked by hand and by the use of a D-Vac (back-pack suction machine). However no larvae of dorantes were found.

In summation, it appears that for the past three years U. dorantes dorantes has been common in southern Florida, with a peak abundance during November, December, and January. It also appears that in 1972 dorantes extended its range far northward along the coast and into the interior sections. All specimens taken in Florida belong to the subspecies dorantes (distinguishing characteristics may be found in Clench (1970)). This fact implies that dorantes was not an introduction from Cuba, as a distinct subspecies occurs there. However, U. dorantes dorantes is common in southeastern Texas ranging as far north as the Dallas area, and thus conceivably it could have reached Florida from a northern route, around the Gulf coast. If so, the records from 1908 and 1916 are perhaps valid after all. It seems incomprehensible, how­ever, that dorantes could have been overlooked for fifty years, especially

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in view of the extensive collecting in south Florida. One is also at a loss to explain the absence of dorantes along the northern Gulf coast.

The most logical explanation, Miller & Miller (1970), is that dorantes was introduced artificially into southern Florida, or possibly transported to the area by the winds of Hurricane Camille in August 1969. Because of its range in Texas, dorantes may well prove to be a late summer visitor throughout northern Florida and coastal Georgia.

ACKNOWLEDGMENTS

I wish to thank T. M. Neal for his assistance and many valuable observations. Also, I am grateful to L. D. Miller, H. V. Weems, C. P. Kimball, and C. Hallas for their observations, comments, and suggestions that led to this paper.

LITERATURE CITED

BURRIS, D. L. 1973. Interesting Florida butterfly records. J. Lepid. Soc. 27: 84. CLENCH, H. K. 1970. New or unusual butterfly records from Florida. J. Lepid. Soc.

24: 240-244. KIMBALL, C. P. 1965. Lepidoptera of Florida. Div. Plant Industry, Gainesville. KLOTS, A. B. 1951. A Field Guide to the Butterflies. Houghton Mifflin, Boston. MILLER, L. D. & J. Y. MILLER. 1970. Pieris protodice and Urbanus dorantes in

southern Florida. J. Lepid. Soc. 29: 244-247. PLISKE, T. E. 1971. Notes on unusual species of Lepidoptera from southern Florida.

J. Lepid. Soc. 25: 294.

BUTTERFLIES ATTRACTED TO AMBER GLASS

During the summer of 1973 I came across two instances of Speyeria spp. being attracted to the amber-colored glass used on the signal lights of motor vehicles.

The first instance involved my motorcycle. I had left the machine parked on a disused logging road on Mt. Sicker, Vancouver Island. I returned just in time to see a butterfly alight on one of the amber lights. On approaching I saw that it was quivering its wings rapidly in the manner often seen when a male butterfly has settled near a receptive female. Its attention was completely focused on the colored glass, and I netted it easily. It was a male Speyeria hydaspe Bdv.

In the second case a pickup truck was the attraction. It was parked near the summit of Mt. Prevost, the butterfly circled it several times, on each circuit dipping towards each of the little amber lights. This insect was quite wary, and I failed to collect it. It was a Speyeria, either S. hydaspe or S. zerene, as these are the only two species occurring in the vicinity.

RICHARD Guppy, Thetis Island, British Columbia, Canada.