Click here for the original journal page (in Acrobat pdf format).

The text below is grayed out because it is not intended to be read. It is a necessarily imperfect OCR of the original and is only used by a search engine.

Journal of the Lepidopterists' Society 40(1), 1986, 55-58

PYRGUS COMMUNIS AND P. ALBESCENS (HESPERIIDAE)

IN NEVADA

George T. Austin

Nevada State Museum and Historical Society, 700 Twin Lakes Drive, Las Vegas, Nevada 89107

ABSTRACT. Based on more than 500 male genitalia, the Pyrgus communis phe-notype replaces the P. albescens phenotype latitudinally and elevationally in Nevada. Intermediates are known where their distributions meet and overlap.

The status of Pyrgus communis (Grote) and Pyrgus albescens Plotz (Hesperiidae: Pyrginae) has been in question up to the present. They have been treated as separate species, as subspecies, or neither (Tilden 1965). Even the most recent regional and taxonomic treatments vary. They were considered subspecies of P. communis by Stanford (in Ferris & Brown 1981) but as full species by Miller and Brown (1981). The two taxa are often segregated by ecology and geography but there are areas of sympatry or near sympatry in southwestern United States and adjacent Mexico. In some latter areas, intermediates are known (Tilden 1965). In others, they are said to occur in close proximity, but no mention is made of intermediates (Ferris 1976, Stanford in Ferris & Brown 1981, Holland 1984); some workers have never seen an intermediate (Ferris, H. A. Freeman, pers. comm.). The present paper summarizes their status and distribution in Nevada.

More than 500 male adults from Nevada in the Nevada State Museum and in the author's collection were examined. The left valva of each was classified into one of three configurations, the variations of which are indicated in Fig. 1. These were assigned to P. albescens, P. communis, and intermediate, and their distributions were mapped.

The valvae of individuals assigned to nominate P. communis have a long and recurved dorsal process terminating in two sharply pointed prongs (Fig. 1). The lengths of the dorsal process and the prongs vary. On some individuals, one of the prongs is shorter than the other; on most they are equal. The valvae of individuals assigned to P. albescens have no dorsal process but usually have a single, short prong anterior to the tip (Fig. 1). Intermediates show various degrees of development in the dorsal process and the double prongs (Fig. 1). There was no difference in wing pattern between the genitalic phenotypes; their seasonal variation is likewise identical.

Individuals of the P. communis phenotype occur throughout Nevada (Fig. 2); those of the P. albescens and intermediate phenotypes occur in southern Nevada except for one P. albescens from Carson City (Fig. 2). At most stations where P. albescens were taken, inter-

56

Journal of the Lepidopterists' Society

communis

jr) -9 -rjrjr)

intermediates albescens

Fig. 1. Variation in the left valvae of Pyrgus communis in Nevada.

mediates and P. communis were taken also. Individuals with intermediate valvae occur only within the range of P. albescens. There is no strict ecological or elevational segregation in southern Nevada, but phenotype proportions do vary. The P. albescens phenotype dominates at lower elevations and latitudes. Intermediates and P. communis become more prominent with increase in elevation and latitude (Table 1, Fig. 2). In the Newberry Mountains, Las Vegas Valley, and the lower slopes of the Spring Mountains, P. albescens accounts for more than 60% of the individuals, and P. communis for less than 6%. At moderate elevations of the Spring Mountains, there is an increase in the P. communis phenotype and at the higher elevations and in Moapa Valley, intermediates predominate.

The Nevada distribution is compatible with that previously noted

Table 1. Proportion of P. albescens, P. communis and intermediate phenotypes from different locations in southern Nevada.

Volume 40, Number 1

57

•o

• •

. <l*

• •

▲

• communis

o albescens

m intermediates

A both

A both and intermediates

V  communis and intermediates

V  albescens and intermediates \o

A •            T

Fig. 2. Distribution of Pyrgus communis in Nevada.

(Tilden 1965) for Pyrgus communis; the latter is a more northern and higher elevation phenotype, P. albescens, a. lower-elevation and more southerly phenotype. Intermediacy, at least in southern Nevada, is greater than previously reported. This indicates that the two pheno-types are closely related, and are probably no more than allopatric subspecies of Pyrgus communis.

58

Journal of the Lepidopterists' Society

Acknowledgments

I thank H. A. Freeman and C. D. Ferris for their comments on these taxa. Thanks are also due two anonymous reviewers for their useful comments on the manuscript.

Literature Cited

Ferris, C. D. 1976. A checklist of the butterflies of Grant County, New Mexico and

vicinity. J. Lepid. Soc. 30:38-49. Ferris, C. D. & F. M. Brown. 1981. Butterflies of the Rocky Mountain States. Univ.

Oklahoma Press, Norman. Holland, R. 1984. Butterflies of two northwest New Mexico mountains. J. Lepid. Soc.

38:220-234. Miller, L. D. & F. M. Brown. 1981. A catalogue/checklist of the butterflies of

America north of Mexico. Lepid. Soc. Mem., No. 2. Tilden, J. W. 1965. A note on Pyrgus communis and Pyrgus albescens (Hesperiidae).

J. Lepid. Soc. 19:91-94.

ANNOUNCEMENT

INAUGURATION OF MANUSCRIPT DATING IN THE JOURNAL

Received and accepted dates will appear at the end of all research reports published in the Journal starting with submissions received in 1986. Such dating is practiced by many scholarly journals. It has at least three purposes. First, it encourages editors, reviewers, and authors to speed manuscript processing. Second, it tells prospective contributors how long manuscript processing might take. Third, it enables more accurate dating of ideas should issues of history or priority arise.

To better serve these purposes, new received dates may be assigned to some revised manuscripts. Examples are those received more than two years after the editor requests them, and those with excessively broadened scopes.

Received and accepted dates should make the Journal more useful to readers and authors alike.

William E. Miller, Editor