Tytthus pygmaeus (Zetterstedt)

Henry, Thomas J., 2012, Revision of the Plant Bug Genus Tytthus (Hemiptera, Heteroptera, Miridae, Phylinae), ZooKeys 220, pp. 1-114 : 65-67

Tytthus pygmaeus (Zetterstedt) Figs 41-44, 175-178

Capsus pygmaeus Zetterstedt 1838: 279 (orig. descrip.). Lectotype designated by Carvalho and Southwood 1955: 24.

Capsus pellucens Boheman 1852: 75 (orig. descrip.). Synonymized by Sahlberg 1868: 176.

Tytthus insignis Douglas and Scott 1866: 247 (orig. descrip.). Synonymized by Saunders 1876: 113.

Capsus (Cyrtorhinus) pygmaeus Thomson 1871: 437 (key).

Leptomerocoris insignis : Walker 1873: 131 (list).

Tytthus pygmaeus : Fieber 1864: 83 (descrip.); Carvalho and Southwood 1955: 23 (descrip., key); Carvalho 1958: 158 (cat.); Kerzhner 1964: 754 (key); Kelton 1980: 289 (distr., host); Kerzhner 1988: 840 (key); Henry and Wheeler 1988: 458 (cat.); Wheeler and Henry 1992: 141 (distr., host); Schuh 1995: 250 (cat.); Scudder 1997: 271 (distr., hosts); Kerzhner and Josifov 1999: 442 (cat.); Wachmann et al. 2004: 271 (note, biol., host, photo); Wheeler 2011: 210 (distr., hosts).

Chlamydatus pygmaeus Reuter 1875a: 31 (key); 1875b: 282 (descrip.).

Cyrtorhinus pygmaeus : Reuter 1883: 554 (descrip., key); Saunders 1892: 283 (descrip., hosts); Van Duzee 1917: 824 (cat.); Butler 1923: 480 (biol.); Kiritshenko 1951: 175 (key); Wagner 1952: 128 (descrip., key).

Tytthus pygmaeus form flavomarginata Stichel 1956: 272 (orig. descrip.). Synonymized by Schuh 1995: 249

Tytthus pygmaeus form flavescens Stichel 1956: 272 (orig. descrip.). Synonymized by Schuh 1995: 249.

Tytthus vagus : Polhemus 1994: 133 (list). See discussion under Tytthus vagus .

Diagnosis.

This highly variable species is distinguished by the black head, with relatively vague interocular spots; entirely pale (European material) to entirely fuscous to black (all North American material) pronotum, with intermediate color forms; very clear or translucent white hemelytra; the fuscous to black antennal segment I, with the apical one fourth pale yellow; antennal segments II–IV uniformly fuscous to black; and the uniformly pale yellow legs. All males and most females of this species are fully macropterous; only a few weakly brachypterous females, with the membrane extending to the apex of the abdomen, have been examined.

Tytthus pygmaeus is superfically similar to the Holarctic Tytthus pubescens in overall size, coloration, and distribution. It can be distinguished from Tytthus pubescens by the fuscous antennal segment I having only the apex pale, the short, recumbent setae on antennal segments I and II, and the variably fuscous to pale pronotum (but never fuscous with pale humeral angles as in Tytthus pubescens ).

Description.

Male (n = 10) (Figs 41, 43): Length to apex of hemelytron 2.50-2.94 mm, length to base of cuneus 1.98-2.14 mm, width across hemelytra 0.94-0.98 mm. Head: Length 0.29-0.32 mm, width across eyes 0.69-0.75 mm, interocular width 0.30-0.32 mm. Labium: Length 1.07-1.12 mm. Antenna: Segment I length 0.30-0.32 mm, II 0.98-1.04 mm, III 0.61-0.62 mm, IV 0.54-0.58 mm. Pronotum: Length 0.35-0.40 mm, basal width 0.77-0.82 mm.

Coloration: Head: Shiny fuscous to black, with a relatively small, yellow, interocular spot near inner margin of each eye; eyes fuscous to dark reddish brown. Labium: Uniformly pale yellow, with apex of segment IV usually brown. Antenna: Segment I, fuscous to black, with only apical one fourth to one third pale yellow; segment II–IV black. Pronotum: Highly variable, ranging from uniformly pale yellow to entirely fuscous to black, with many intermediate forms, including all of disc dark and anterior half yellow and almost entirely dark with yellow across anterior margin and through middle of calli; some yellow specimens with only fuscous posterior angles. Mesoscutum and Scutellum: Uniformly fuscous to black. Hemelytron: Uniformly clear to very pale translucent white. Ostiolar evaporative area: Fuscous to black, even on palest specimens. Ventral surface: Thorax uniformly fuscous; abdomen fuscous along lateral margins and genital capsule, ventral area and sides pale yellow to whitish. Legs: Uniformly pale yellow.

Structure, texture, and vestiture: Head: Shiny, impunctate, much broader than long; set with numerous, long, erect and semierect setae on vertex and frons. Labium: Extending to apices of meso- or bases of metacoxae; segment I extending just beyond head to anterior margin of xyphus just before procoxae. Antenna: Segment I sparsely set with recumbent setae and two, long, erect, subapical, bristlelike setae; segment II, thickly set with short, recumbent and semierect setae. Pronotum: Trapeziform, anterior angles nearly weakly rounded; lateral margins straight, gradually widening to posterior angles; posterior margin nearly straight or only weakly sintuate. Mesoscutum: Broadly exposed. Scutellum: Equilateral; sparsely set with scattered relatively short, semierect setae. Hemelytra: Macropterous, cuneus and membrane fully developed, extending well beyond apex of abdomen; evenly set with recumbent setae.

Male genitalia: Left paramere (Fig. 175): Right arm long, broad, apically blunt; left arm short, apically pointed. Right paramere (Fig. 176): Elongate oval. Endosoma (Fig. 177): Strongly C-shaped, apically blunt. Phallotheca (Fig. 178): Slender, apically acute.

Female (n = 10) (Figs 42, 44): Length to apex of hemelytron 2.92-3.17 mm, length to base of cuneus 2.21-2.34 mm, width across hemelytra 1.20-1.31 mm. Head: Length 0.34-0.35 mm, width across eyes 0.74-0.75 mm, interocular width 0.34-0.35 mm. Labium: Length 1.12-1.20 mm. Antenna: Segment I length 0.27-0.29 mm, II 0.86-0.88 mm, III 0.61-0.62 mm, IV 0.54-0.58 mm. Pronotum: Length 0.40-0.42 mm, basal width 0.91-0.96 mm.

Hosts.

In North America, this species has been recorded from sedges, Carex spp. ( Kelton 1980) and Carex urtriculata [ Cyperaceae ] (Wheeler 2011). In the Old World, it has been taken on European beachgrass, Ammophila arenaria (L.) Link [ Poaceae ], and on rushes, Juncus spp., where it feeds on the delphacid Conomelus anceps (Germar) ( Scudder 1957, Wheeler and Henry 1982). Rothschild (1963) studied the biology and illustrated the fifth instar. Ehanno (1987) studied the life history in France and reported Juncus effusus L. (as conglomeratus L.) [ Juncaceae ] and Typha sp. [ Typhaceae ] as hosts.

Distribution.

This Holarctic species is known in Canada from Alberta, British Columbia, Labrador, Newfoundland, Ontario, Saskatchewan, and Yukon Territory and in the United States from New Mexico and Wyoming ( Kelton 1980, Henry and Wheeler 1988, Wheeler and Henry 1992, Maw et al. 2000, Wheeler 2011). Colorado is a new state record.

In the Old World, it is known in Asia from Russia (East Siberia, Far East, and West Siberia) and in Europe from Austria, Byelorussia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Latvia, Luxembourg, Moldavia, The Netherlands, Norway, Poland, Russia (Central European and North European territories), Slovakia, Sweden, and the United Kingdom ( Carvalho and Southwood 1955, Wheeler and Henry 1992, Kerzhner and Josifov 1999).

Specimens examined.

CANADA:Alberta: 25 mi N of Nordegg, 52.73804°N, 116.2332°W, 1298 m, 20 Jul 1987, S. A. Marshall, Carex sp. ( Cyperaceae ), 1 ♂ (00382161) (DEBU). Coal Valley, 53.08°N, 116.8°W, 31 Aug 1970, L. A. Kelton, 1 ♀ (00167065) (CNC). Newfoundland and Labrador: Hebron, 58.2°N, 62.63333°W, 19 Jul 1954, J. F. McAlpine, 2;m (00167056, 00167057), 6 ♀♀ (00167058 - 00167063) (CNC). Ontario: Elmira, 13 Jun 1958 - 19 Jun 1958, J. Juillet, 1 ♂ (00167067) (CNC). Elora, 43.68242°N, 80.43364°W, 384 m, 27 Jun 1977, K. Barber, 1 ♂ (00382166) (DEBU). Guelph, 43.55°N, 80.25°W, 323 m, 24 Jun 1977, P. R. Heels, 3 ♂♂ (00382162 - 00382164), 1 ♀ (00382165) (DEBU). Iroquois Falls, 48.77177°N, 80.66576°W, 238 m, 30 Jun 1987, J. R. Vockeroth, 2 ♂♂ (00166943, 00166992) (CNC). Marmora, 44.48333°N, 77.68333°W, 25 Jun 1952, J. R. Vockeroth, 1 ♂ (00166945) (CNC). Ottawa, 45.39079°N, 75.70324°W, 71 m, 15 Jul 1964, J. R. Vockeroth, 1 ♀ (00167066) (CNC). Saskatchewan: Christopher Lake, 53.56666°N, 105.83333°W, 11 Jun 1959, A. and J. Brooks, 2 ♀♀ (00166939, 00166940) (CNC); 13 Jul 1959, A. and J. Brooks, 3 ♀♀ (00166934 - 00166936) (CNC); 15 Jul 1959, A. and J. Brooks, 1 ♂ (00166929), 2 ♀♀ (00166937, 00166938), 1 nymph (00166928) (CNC). Yukon Territory: 14 mi E of Dawson, 64.01938°N, 139.10712°W, 396 m, 29 Jul 1962, R. E. Leech, 1 ♂ (00166944) (CNC). 58 mi E of Dawson, Gravel Lake, 64.06666°N, 137.49935°W, 625 m, 10 Aug 1962, R. E. Leech, 1 ♂ (00166941) (CNC); 12 Aug 1962, R. E. Leech, 1 ♀ (00166942) (CNC). Takhini Hot Springs, 60.85°N, 135.51666°W, 732 m, 19 Aug 1962, R. E. Leech, Betula sp. ( Betulaceae ), 1 ♀ (00166999) (CNC); 19 Aug 1962, P. J. Skitsko, 1 ♂ (00166989) (CNC). FINLAND:Lansi-Suomen: Raisio, 60.4833°N, 22.1833°E, 28 m, R. Linnavuori, 2 ♂♂ (00138748, 00138748) (AMNH). Locality unknown, Reuter, 1 ♀ (00235138) (ZISP). Southern Finland: Tvarminne, 12 Aug 1960, G.G.E. Scudder, 1 ♀ (00167068) (CNC). Ob Rovaniemi Posa, 29 Jul. 1950, H. Lindberg, 1 ♀ (NMW). KYRGYZSTAN: Upper course of Gava-Say [Gava] River, 41.16666°N, 72.86666°E, 10 Aug 1937, A. N. Kiritshenko, 1 ♂ (00235045) (ZISP). RUSSIAN FEDERATION:Amur Prov.: Klimoutsy, 40 km W of Svobodnyi, 51.4667°N, 127.5833°E, 242 m, 30 Jun 1959, I. M. Kerzhner, 1 ♂ (00235048) (ZISP). Simonovo, 75 km W Svobodnyi, 51.45°N, 126.96666°E, 19 Jul 1959, I. M. Kerzhner, 1 ♀ (00235144) (ZISP). Chita Prov.: Kharanor, 50.0833°N, 116.6667°E, 12 Jul 1963, I. M. Kerzhner, 10 ♂♂ (00235035 - 00235044), 6 ♀♀ (00235146 - 00235151) (ZISP). Irkutsk Prov.: Khargino [Kharga], SW Baikal, 52.31666°N, 105.76666°E, 19 Jul 1950, A. N. Kiritshenko, 3 ♀♀ (00235141 - 00235143) (ZISP). Kamchatka Prov.: Uzon volcano, 54.51666°N, 159.8°E, 11 Aug 1985, I. M. Kerzhner, 2 ♂♂ (00235049, 00235050), 3 ♀♀ (00235049, 00235050), 1 nymph (00235049) (ZISP). Komi Rep.: Vodnyy, 63.5°N, 53.4°E, 21 Aug 1964, collector unknown, 1 ♀ (00235165) (ZISP). Kostroma Prov.: Shilovo, ~25 km W of Manturovo, 58.33333°N, 44.33333°E, 12 Jul 1981, Veselova, 2 ♀♀ (00235166) (ZISP). Leningrad Prov.: Berezhok 20 km W Sosnovo, 60.55°N, 29.91666°E, 01 Aug 1961 - 15 Aug 1961, I. M. Kerzhner, 1 ♂ (00235034) (ZISP). Lebyazhye, 59.93333°N, 29.41666°E, 30 Jun 1898, Bianchi, 1 ♀ (00235139) (ZISP). Serezhino, 59.43°N, 28.32°E, 24 Aug 1895, Bianchi, 1 ♀ (00235140) (ZISP). Sakhalin Prov.: Novoaleksandrovsk, South Sakhalin, 47°N, 142.7°E, 07 Sep 1973, I. M. Kerzhner, 1 ♀ (00235164) (ZISP). Yakutia Rep.: Amga [Amginskaya Sloboda], 60.9°N, 132.01666°E, 12 Aug 1925, Bianchi, 1 ♀ (00235145) (ZISP). Balagannakh, 30 km ESE of Ust’ -Nera, 64.498°N, 143.857°E, 04 Jul 1974, N.N. Vinokurov, 3 ♂♂ (00235046), 2 nymphs (00235131) (ZISP); 06 Jul 1974, Narchuk, 1 ♂ (00235047) (ZISP); 08 Jul 1974, Narchuk, 1 ♀ (00235160) (ZISP). Batagay on Yana river, NE Yakutia (80 km E Verkhoyansk), 67.65°N, 134.63333°E, 25 Jul 1974, N.N. Vinokurov, 4 ♀♀ (00235157, 00235158) (ZISP). Icing Bulus on Lena River 100 km upstream Yakutsk, Central Yakutia, 62.83333°N, 129.73333°E, 05 Jul 1996 - 07 Jul 1996, Watabe, 1 ♂ (00235051) (ZISP). Kolyma, Zyryanka, 65.73333°N, 150.91666°E, 05 Jul 1973, N.N. Vinokurov, 4 ♀♀ (00235152 - 00235155) (ZISP); 07 Jul 1973, N.N. Vinokurov, 1 ♀ (00235156) (ZISP). Mouth of Kharayuryakh River, NNW Artyk, 64.33333°N, 145.01666°E, 14 Jul 1974, Narchuk, 1 ♀ (00235159) (ZISP). Nr Olekminsk, 60.38333°N, 120.18333°E, 01 Aug 1974, N.N. Vinokurov, 9 ♀♀ (00235161 - 00235163) (ZISP). UNITED KINGDOM:England:Berkshire Co.: Burnham Beeches, 51.54932°N, 0.63311°W, 57 m, 17 Jul 1960, G. G. E. Scudder, 2 ♂♂ (00166990, 00166993), 1 ♀ (00166997) (CNC). East Sussex Co.: Camber, 05 Sep 1964, G.G.E. Scudder, 1 ♀ (00167064) (CNC). Oxfordshire Co.: Cothill, 51.69446°N, 1.33529°W, 82 m, 14 Jul 1960, G. G. E. Scudder, 1 ♀ (00166998) (CNC). Kennington, Berks., 51.71877°N, 1.24105°W, 58 m, 15 Jul 1960, G. G. E. Scudder, 7 ♂♂ (00166984, 00166986 - 00166988, 00166994 - 00166996), 1 nymph (00166985) (CNC). Wolvercote, 51.7854°N, 1.2902°W, 60 m, 14 Jul 1960, G. G. E. Scudder, 1 ♂ (00166930), 2 ♀♀ (00166926, 00166927) (CNC). Somerset Co.: Porlock, 51.2°N, 3.6667°W, 399 m, 11 Jul 1960, G. G. E. Scudder, 21 ♂♂ (00166947 - 00166953, 00166961 - 00166971, 00166981 - 00166983), 16 ♀♀ (00166954 - 00166960, 00166972 - 00166980) (CNC). Locality unknown: unknown, V. Jakovlev coll., 1 ♂ (00235032), 1 ♀ (00235137) (ZISP). UNITED STATES:Colorado:Garfield Co.: Grizzly Creek, 24 Jul 1896, C. F. Baker, 1 nymph (00161848) (USNM). New Mexico:Sandoval Co.: Valles Caldera National Preserve, East Fork Jemez River, 35.8483°N, 106.49048°W, 01 Aug 2008, A. G. Wheeler, Jr., Carex utriculata ( Cyperaceae ), 1 ♀ (00162160) (USNM). Wyoming:Laramie Co.: Laramie, 41.31°N, 105.59°W, 08 Jul 1947 - 09 Jul 1947, D. G. Denning, 1 ♂ (00166946) (CNC).