Plagiognathus delicatus (Uhler)

SCHUH, RANDALL T., 2001, Revision Of New World Plagiognathus Fieber, With Comments On The Palearctic Fauna And The Description Of A New Genus (Heteroptera: Miridae: Phylinae), Bulletin of the American Museum of Natural History 2001 (266), pp. 1-267 : 69-70

Plagiognathus delicatus (Uhler) Figures 7 , 16 , 22

Psallus delicatus Uhler, 1887: 34 (n. sp.).

Gerhardiella delicatus: Van Duzee, 1916b: 243 (n. comb.).

Plagiognathus delicatus: Knight, 1923: 433 (n. comb.).

DIAGNOSIS: Recognized by the relatively small size, coloration of dorsum dominated by orange, calli usually darkened (fig. 7), antennal segment 1 black, segment 2 usually pale, sometimes black basally (fig. 16), tibial spines with tiny dark spots at bases, tibiae pale at articulation with femur, and the vesica being relatively short and stout with a relatively broad flange and long apical spines (fig. 22). Distinguished from cornicola by the tibiae being pale at articulation with the femora and the tibial spines with tiny black spots at bases, whereas in cornicola tibiae dark at articulation with femur and black spots at bases of tibial spines larger. Also, vesica in delicatus relatively stout with long apical spines and with base nearly reaching level of gonopore (fig. 22), whereas vesica in cornicola longer and more slender (fig. 22). Coloration almost always heavily orange, whereas cornicola mostly dark brown or castaneous in some populations. Similar in coloration also to viticola (fig. 14), but that species smaller with all antennal segments entirely pale (fig. 19) and tibial spines without dark spots at bases.

REDESCRIPTION: Male: Moderately small, relatively stout­bodied; total length 3.14– 3.40, length apex clypeus–cuneal fracture 2.12–2.24, width across pronotum 1.05–1.14. COLORATION (fig. 7): Coloration of dorsum always somewhat mottled, varying from orange or red­orange to brown; calli usually darker than remainder of pronotum; membrane pale to very weakly fumose, veins pale; antennal segment 1 usually dark except for pale apical annulus, segment 2 variable, either dark at extreme base with remainder pale, or completely pale (fig. 16), segments 3 and 4 pale to infuscate; clypeus castaneous, contrasting with adjacent areas of head; labium varying from mostly pale to weakly infuscate; venter mottled with pale and orange or brown, metathoracic scent­gland evaporatory area pale; legs varying from almost entirely pale, including coxae, to having coxae, trochanters, and femora weakly infuscate or orange; femora with some dark spots; tibiae always with pale background coloration and small, but obvious, dark spots at the bases of the tibial spines; tibiae pale at articulation with femora. SURFACE AND VESTITURE: Dorsum weakly granular, smooth, weakly shining. Vestiture of dorsum composed of recumbent, pale, golden, shining, simple setae. STRUCTURE: Elongate­ovoid, lateral corial margins weakly convex; frons weakly convex, slightly projecting beyond anterior mar­ gin of eyes, clypeus barely visible from above; anteocular distance 1.5 times diameter of antennal segment 1; head projecting below eye by 0.5 times diameter of antennal segment 1; antennal segment 2 short, only slightly longer than width of head; labium relatively short, not quite reaching apex of middle coxae. GENITALIA (fig. 22): Body of vesica relatively stout, very strongly curving, U­shaped, base of vesica reaching level of secondary gonopore; posterior apical spine long, nearly straight and weakly angled relative to body of vesica, anterior spine distinctly longer than posterior, angled near apex, and more strongly angled relative to body of vesica than posterior spine; vesical flange moderately developed, reaching to base of secondary gonopore.

Female: Very similar to male in coloration but body more strongly ovoid in outline. Total length 3.06–3.30, length apex clypeus–cuneal fracture 2.12–2.34, width across pronotum 1.10–1.19.

HOST: Gleditsia triacanthos (Fabaceae) . All other records are nonbreeding.

DISTRIBUTION: Eastern North America, as far west as the foothills of the Rocky Mountains in Colorado.

DISCUSSION: This species was originally placed by Uhler in Psallus , but it has subsequently been placed in Plagiognathus by most authors, and the form of the male genitalia confirms that placement. Concerning the origins of this taxon, as he knew it, Uhler said only that ‘‘A dark variety of this species has been captured in the highlands of Georgia’’. The type locality has therefore been treated as Georgia. Knight (1923, 1941) recorded delicatus as occurring on Gleditsia triacanthos from Illinois east to Virginia and north to New York. Wheeler and Henry (1976) discussed the occurrence of delicatus on Gleditsia . I have not seen material of delicatus from as far south as Georgia. Nonetheless, I am using the name delicatus in the sense of Knight (1923, 1941) and Wheeler and Henry (1976), because clearly the taxon feeding on Gleditsia is distinct from the one commonly found on Cornus . The distribution is now known to extend as far west as the area around Denver, Colorado.

No material exists in the USNM collections that can be documented as having been examined by Uhler in the preparation of his description of delicatus . I am therefore designating a neotype (male) to promote stability of concept for this taxon. It bears the following label data and is deposited in the United States National Museum of Natural History:

USA: VA: Montgomery Co., Blacksburg, Va. Polytech. Inst., 3 Je 1989, A. G. Wheeler, Jr.; Gleditsia triacanthos ; Neotype Psallus delicatus Uhler , det R. T. Schuh

Populations from the Northeast are heavily weighted towards female specimens, whereas those from farther west, including Kansas and Colorado, show an almost equal distribution of males and females.

SPECIMENS EXAMINED: CANADA.— Ontario: Fonthill, June 8, 1962, Kelton and Thorpe, ex Fabaceae , 13 (CNC). Niagara Falls, June 8, 1962, Kelton and Thorpe, Gleditsia sp. (Fabaceae) , 63, 9♀ (CNC). Pt. Pelee, June 23, 1931, G. S. Walley, 203, 30♀ (CNC). USA.— Colorado: Arapahoe Co.: Englewood, June 9, 1985, J. T. and D. A. Polhemus, Gleditsia triacanthos (Fabaceae) , 143, 4♀ (JTP). Douglas Co.: Chatfield State Park, June 3, 1992, J. T. Polhemus, 2♀ (JTP). Waterton, June 19, 1984, D. A. Polhemus, 13, 3♀ (JTP). Illinois: Hardin Co.: Elizabethtown, May 27, 1932, H. L. Dozier, 1♀ (AMNH). Jackson Co.: Grand Tower, May 12, 1932, Frison, Ross, and Mohr, 13, 1♀ (AMNH). Iowa: Story Co.: Ames, June 14, 1927, H. H. Knight, 13, 1♀ (TAMU). Ames, June 21, 1964, H. H. Knight, 2♀ (USNM). Ames, June 3, 1955, H. H. Knight, 23, 1♀ (USNM). Ames, June 9, 1927 – July 3, 1931, H. M. Harris, 23, 2♀ (TAMU). Kansas: Douglas Co.: Lawrence vicinity, May 15, 1971, V. P. Gapud, 33, 6♀ (KU). Riley Co.: Manhattan, May 12, 1917, P. L. Nixon, 23 (PDA). Louisiana: Baton Rouge Co.: Baton Rouge, April 26, 1986 – May 8, 1988, D. A. Rider, E. G. Riley, 63, 1♀ (DAR). LSU Campus, April 9, 1986 – May 9, 1986, D. A. Rider, 43 (DAR). East Baton Rouge Co.: 1.2 mi S of Central, E of LA Rt 3035, May 19, 1988, C. B. Barr, 13 (LSU). Baton Rouge, April 21, 1987, E. G. Riley, 13 (LSU). LSU Campus, May 16, 1985, D. A. Rider, 13 (LSU). Natchez Co.: Red Dirt Wildlife Man. Area, April 29, 1985, D. A. Rider, 23 (DAR). St. Landry Co.: 1 mi N of Port Barre on Hwy 103, April 27, 1986, E. G. Riley and D. A. Rider, 3♀ (DAR, LSU). Maryland: Montgomery Co.: Rockville, Rt 28, May 11, 1985, T. J. Henry and A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 43, 3♀ (USNM). Prince Georges Co.: College Park, University of Maryland, June 4, 1988, T. J. Henry, Gleditsia triacanthos (Fabaceae) , 5♀ (USNM). Missouri: Boone Co.: Columbia , May 20, 1981, R. L. Blinn, Gleditsia triacanthos (Fabaceae) , 13, 1♀ (DAR). New York: Genesee Co.: Batavia, July 1, 1915, H. H. Knight, 3♀ (CAS). Nassau Co.: East Meadow near Rt 25 on Bluebird Drive, June 18, 1986, M. D. Schwartz, Gleditsia triacanthos (Fabaceae) , 21♀ (AMNH). Sagamore Hill Natl. Hist. Site, June 24, 1984, M. D. Schwartz, Gleditsia triacanthos (Fabaceae) , 33♀ (AMNH). Queens Co.: Corona Heights, jct Van Doren St. and 108th St., June 3, 1986, M. D. Schwartz, Quercus palustris (Fagaceae) , 1♀ (AMNH). Suffolk Co.: Cold Spring Harbor, Long Island, July 2, 1920, P. Butler, 1♀ (CAS). Pennsylvania: Allegheny Co.: Coraopolis, Morten Nursery, May 26, 1976, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 1♀ (AMNH). Centre Co.: State College, June 10, 1977, Schuh, Henry, Wheeler, Gleditsia triacanthos (Fabaceae) , 62♀ (AMNH). State College, University Drive, June 1, 1977, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 13, 2♀ (PDA). Cumberland Co.: Allen, May 27, 1975, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 33, 3♀ (PDA). Camp Hill, June 7, 1983, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 43, 3♀ (PDA). Dauphin Co.: Harrisburg, East Harrisburg Cemetery, June 19, 1975, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 33, 3♀ (PDA). Harrisburg, East Harrisburg Cemetery, June 9, 1975, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 1♀ (AMNH). Harrisburg, Latsha, June 9, 1978, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 13 (PDA). Hershey, May 25, 1976, T. J. Henry, Gleditsia triacanthos (Fabaceae) , 13, 3♀ (PDA). Hershey, May 28, 1976, T. J. Henry, Gleditsia triacanthos (Fabaceae) , 1♀ (AMNH). Hershey, St. Joan of Arc School, June 1, 1975, T. J. Henry, Gleditsia triacanthos (Fabaceae) , 43, 18♀ (PDA). Erie Co.: Fariview, Fairview Nurseries, June 5, 1974, T. J. Henry and A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 23, 6♀ (PDA). Indiana Co.: Indiana, July 7, 1963, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 1♀ (PDA). Texas: Brazos Co.: Bry­ an, April 27, 1966, J. C. Schaffner, 33 (TAMU). College Station, April 21, 1933, H. J. Reinhard, 13, 1♀ (USNM). College Station, April 25, 1970, R. C. Phelps, 13 (TAMU). College Station, May 1, 1935 – May 18, 1937, H. G. Johnston, 4♀ (TAMU). Collins Co.: 7 mi E of Blue Ridge, May 3, 1998, J. C. Schaffner, 1♀ (TAMU). Hill Co.: 2 mi W of West, April 21, 1972, J. C. Schaffner, Gleditsia triacanthos (Fabaceae) , 1♀ (TAMU). McClennan Co.: 3 mi W of West, May 3, 1971, J. C. Schaffner, 1♀ (TAMU). Virginia: Montgomery Co.: Blacksburg, Virginia Polytechnic Inst., June 3, 1989, A. G. Wheeler, Jr., Gleditsia triacanthos (Fabaceae) , 23, 3♀ (USNM). Washington, D.C.: May 17, 1915, O. Heidemann, 3♀ (PDA).

Figures

Fig. 7. Habitus figures of Nearctic Plagiognathus spp. (see p. 263 for localities).

Fig. 16. Antennal segments 1 and 2 of Nearctic Plagiognathus spp.

Fig. 22. Male genitalia of Nearctic Plagiognathus spp. fl = flange.