Pholetesor masoni, Whitfield, 2006

Whitfield, James B., 2006, Revision of the Nearctic species of the genus Pholetesor Mason (Hymenoptera: Braconidae), Zootaxa 1144 (1), pp. 1-94 : 27-30

Pholetesor masoni , new species

( figs. 19 , 36 , 42 , 62 , 80 )

Holotype female. Body length 1.9 mm, forewing length 2.0.

Head. Frons 1.3x broader at midheight than long down midline, weakly punctate; inner margins of eyes weakly converging. Antennae very dark brown throughout, approximately same length as forewing; all but distal 5 flagellomeres with 2 ranks of placodes; flagellomere 2 3.5x as long as broad; flagellomere 14 1.5x as long as broad. Palpi light yellow­brown, basal segments slightly darker. Head in dorsal view twice broader than long.

Mesosoma . Mesoscutum shallowly but distinctly punctate except smoother near scutoscutellar scrobe, just narrower anterior to tegulae than head, surface between punctures with dull metallic sheen. Scutoscutellar scrobe moderately broad, composed of 10–12 sharp punctures. Scutellar disc distinctly punctate, hairy, shinier between punctures than mesoscutum, about 1.2x as long as maximum breadth. Metanotum weakly retracted from scutellum anteriorly, shallowly excavated mesad to sublateral setiferous projections; well­defined transverse carinae at about 0.3–0.4 of length on either side, setting off transverse, more posterior depressions which are crossed by several short carinulae. Propodeum 1.8x as broad as long at longest point, coarsely rugose, with weakly superimposed, more or less pentagonal areola and transverse carinae (areola approximately 0.3 or less as broad as entire propodeum).

Legs. All coxae dark brown to black. Trochanters and bases of femora deep brown to black; meso­and meta­thoracic femora distally darker brown than prothoracic. Tibiae and tarsi of all legs lighter yellow­brown. Spines on outer faces of hind tibiae approximately 20 in number, somewhat thinner and more difficult to distinguish from normal hairs than in most species. Apical spurs of hind tibiae subequal in length (inner very slightly longer), less than 0.4 as long as hind basitarsus.

Wings. Tegulae dark brown, translucent. Forewing venation strongly pigmented, darker brown, except virtually colorless M­Cu and 1A–2A. R1 longer than stigma, approximately 4x as long as distance from its tip to end of 3Rs fold along wing edge. 2r, 1Rs subequal in length, meeting at distinct but obtuse angle. Vannal lobe of hindwing weakly flattened subapically, with even fringe of long hairs.

Metasoma. Tergite I strongly rugose, 1.4x as long as broad at midlength; lateral margins diverging slightly posteriorly, strongly rounding at apex; medioapically with suggestion of small, longitudinal depression. Tergite II subquadrate, 2.0x broader than long down midline, with weakly rounded anterolateral corners; surface strongly rugose (but more finely than in tergite I); hind margin marked by crenulate, nearly straight furrow. Tergum III approximately same length as II, roughened anteromedially, becoming smooth and similar to following terga posteriorly. Succeeding terga unsculptured, unmodified, overlapping. Laterotergites medium brown, concolorous with hind tibiae. Hypopygium long, 1.2–1.3x length of hind basitarsus, evenly sclerotized to medial fold, with 60­degree angled tip in profile. Ovipositor sheaths fusiform, hardly decurved (even basally), sparsely hairy, with hairs mostly on apical half of broadened portions; entire length of sheaths subequal with that of hind basitarsi. Ovipositor very weakly decurved.

Males. Body length 1.8–2.1 mm, forewing length 1.9–2.1 mm. Antennae clearly longer than forewing, with all but distal 3 flagellomeres with 2 ranks of placodes; apical flagellomeres more slender than in females (flagellomere 14 2.0–2.2x as long as broad). Propodeal and metasomal sculpturing very similar to females except porpodeal areola tends to be slightly narrower and less distinctly pentagonal. Some dark males have smoother and shinier sculpturing over the metasomal tergites, with a stronger longitudinal trend. Occasionally the second tergite is more trapezoidal (broader apically) than in associated females.

Variation. Female body length 1.9–2.1mm, forewing length 2.0– 2.2mm. In all available series, there is some variation in the strength and distinctness of the propodeal areola and transverse carinae, as well as the rugose background sculpturing. Eastern specimens seem to generally have lighter leg coloration and coarser metasomal and propodeal sculpturing. I have seen a few specimens from the southwestern U.S. which have unusually strong transverse carinae; their assignment to this species is tentative.

Final instar larva. Labium with one pair of large setae on short tubercles. Maxillae each with one seta. Mandibles set with approximately 14 long teeth (not counting bifid tip).

Cocoons. All reared individuals emerged from cocoons of Bucculatrix spp. A thin cocoon is spun within that of the host after emergence from the host larva/prepupa.

Material examined. Holotype female: CALIFORNIA. San Mateo Co., San Bruno Mts., 31­III­1983 (J.B. Whitfield). Paratypes: CALIFORNIA: San Mateo Co., San Bruno Mts., 1 female, 4 males, 31­III­1983; 3 males, 3­IV­1982, 3 males, 14­IV­1983; 1 female, 11 males, 16­IV­1982; 1 female, 2 males, 21­IV­1982; 1 female, 1 male, 21­IV­1981, 1 female, 17­V­1981, 2 females, 1 male, 15­IV­1982, ex Bucculatrix on Baccharis (D.L. Wagner) , 1 male, 28­V­1982, ex Bucculatrix on Baccharis (D.L. Wagner) . All collected by J.B. Whitfield except where noted. Holoype deposited in USNM, paratypes in USNM, CNC, U. C. Berkeley collections.

Other material: ALBERTA. Lake Louise, 1 female, 29­VII­1935 (Melander). ARIZONA: Tucson, 1 male, 9­IV­1906 (collector not given). BRITISH COLUMBIA: East Kootenays, top of Moyle Mt. 6868', 1 female, 16­VII­1959 (H.B. Leech). CALIFORNIA: Alameda Co., Berkeley Hills, 1 female, 6­VIII­1982 (J.B. Whitfield), 1 female, 13­VI­1983 (JBW), 1 male, 20­IV­1982 (JBW), 1 male, 3/ 5­III­1983, ex Bucculatrix on Baccharis pilularis (J.B. Whitfield & D.L. Wagner) , 1 male, 17­V­1962 (no collector given). Chabot Regional Park, 1 female, 12­VII­1980 (JBW). Contra Costa Co., 2 mi. SE Lafayette, 1 male, 18­IV­1968 (W.J. Turner). Moraga, 1 female, 24­VI­1971 (D.G. Denning), 2 mi. W. Pittsburg, 1 female, 19­IX­1957 (J.A. Powell). Redwood Regional Park, 1 male, 2­IX­1980 (JBW). Tilden Regional Park, 2 males, 30­VII–28­X­ 1980 (J. Fraser), 1 male, 11­VIII­1982, ex Bucculatrix on Baccharis pilularis (JBW) , 1 male, 25­V­1983 (JBW). Inyo Co., Owens Lake Dunes, 2 females, 17­V­1978, at blacklight (D. Giuliani). Surprise Canyon, 1 female, 5­V­1961 (F.D. Parker). Kern Co., Sand Canyon, 3 mi. W Brown, 2 females, 7­IV­1966 (R.O. Schuster). Los Angeles Co., Frank Bonelli Park, 1 female, 20­II­1984, ex Bucculatrix on Baccharis (D.L. Wagner) . Marin Co., nr. Alpine Lake, 1 female, 26­VI–2­VII­1970, malaise (D. Munroe). Inverness, 1 female, 25­II­1962 (C.A. Toschi). Riverside Co., Forest Home, 1 female, 25­V­1935 (Melander). Riverside, 1 female, 3 males, 15–23­IV­1948, on Artemisia (has Bucculatrix cocoon attached) (P.H. Timberlake), 1 female, V­1935 (Melander). San Diego Co., Borrego Springs, 1 male, 30­III­1960 (M. Wasbauer). Escondido, 1 female, 15­VII­1941 (R.H. Beamer). San Francisco Co., San Francisco, 3 females, 25­III­1933, reared from Baccharis (H.H. Keifer) . San Luis Obispo Co., Oso Flaco Lake, 1 female, 13­VIII­1959 (P.M. Marsh). San Mateo Co., San Bruno Mts., 1 male, 18­IV­1976, on flowers Heracleum lanatum (P.H. Arnaud) , 1 female, 10­V­1981 (JBW), 1 female, 1 male, 25­II­1984 (JBW). Santa Barbara Co., Santa Cruz Isl., Cascada, 1 female, 8­V­1968 (R.O. Schuster), Christi Beach, 1 female, 20­IV­1966 (J.A. Powell). Sonoma Co., Bodega Bay, 1 female, 21­III­ 1983, ex Bucculatrix on Baccharis (D.L. Wagner) , 1 female, 21­III­1983 (JBW), 1 mi. SE, 1 female, 27­IV­1983, ex Bucculatrix on Baccharis pilularis (D.L. Wagner) . Sutter Co., Live Oak Park, 1 female, 2 males, 24­V­1944 (no collector given).

INDIANA. Lafayette, 1 female, V­1918 (J.M. Aldrich). MARYLAND. North River, 1 female, 3 males, 25­VII­1941, ex Bucculatrix sp. (J.F.G. Clarke) . MASSACHUSETTS. Forest Hills, 1 female, 17­V­1913 (no collector given). Franklin, 1 male, 16­V­1916 (no collector given). Greenfield, 1 female, 1­IV­1914 (Melander). MEXICO. Chiapas, San Cristobal Las Casa, 1 male, 1/ 2­I­1975 (D. Green, P. Craig). D.F., Desiertos de los Leones, 1 female, 27­III­1946 (J. & D. Pallister). MICHIGAN. Allegan Co., 1 female, 18­V­1959 ( R. & K. Dreisbach). Berrien Co. , Galien , 1 female, 28­V­1974 (D.J. Miller), 1 male, 2­ VIII­1974 (D.J. Miller). Delta Co. , 1 female, 8­VIII­1953 ( R. R. Dreisbach ). East Lansing , 1 male, 24­V­1957 (no collector given). Tuscola Co. , 1 male, 30­V­1952 ( R. R. Dreisbach) .

MINNESOTA. St. Paul, Battle Creek , 1 female, 20­V­1922 (W.E. Hoffman). NEW

YORK. Chatham, 1 female, 1 male, 30­VII­1904 (A.O. Morse). Ithaca, 1 female, 1 male, 9­VII­1904 (no collector given), 1 male, 13­VI­1947 (no collector given). Lancaster, 1 female, 25­VII­1946 ( R. H. Beamer). The Hook, McLean Res., 1 male, 31­VIII­1925 (no collector given). NORTH CAROLINA. Avery Co., Linville , 1 male, 12­VIII­1977 ( NCDA). Swain Co. , Smokemont , 1 female, 15­VI­1977 ( NCDA). NOVA SCOTIA. Halifax , 3 males, 23­VI­1952, ex Bucculatrix on Aster (J. McDunnough) , 1 female, 30­IX­ 1951, ex Bucculatrix on Aster (J. McDunnough) . OHIO. Barberton , 1 female, 8­VII­1936 (L.J. Lipovsky), 1 male, 30­VI­1936 (L.J. Lipovsky). Summit Co. , 1 male, 24­VI­1937 (L.J. Lipovsky), 1 female, 9­VI­1937 (L.J. Lipovsky). ONTARIO. Aylmer West , 11 females, 4 males, 30­V­1972, malaise trap (no collector given). Crow Lake , Marmara Area , 1 female, 10­VIII­1959 (L.K. Smith). Maynooth , 1 female, 5­IX­1953 (J.F. McAlpine). McDonald Id., 2 females, IX­X­1976 (Reid). Ottawa , 1 male, 25­V­1944, ex leafminer on Aster (J. McDunnough) , 1 male, 25­VII­1957 (J.E.H. Martin). Simcoe , 1 male, 11­IX­1957, ex Bucculatrix sp. (Freeman & Lewis). St. Lawrence Id. Nat. Pk. , Thwartway Id., 2 females, VII­VIII­1976 (Reid). Toronto , 1 female, 31­V­1909 (M.C. VanDuzee). QUEBEC. Fairy Lake, 1 female, 1 male, 20­II­1957, ex Bucculatrix sp. (Freeman & Lewis). WYOMING. Teton Pass, E. side, 74­8400', 1 male, 17­VIII­1961 (B.H. Poole) .

Hosts. In California, Bucculatrix spp. on Baccharis pilularis provide most of the rearing records, but I suspect other species of Bucculatrix on shrubby composites may also serve as hosts. There is one record (a series of 4 specimens) from Bucculatrix on Artemisia from southern California; most records from Artemisia are of P. variabilis . In the East, records from Bucculatrix on Aster spp. are widespread enough to suggest common occurrence on those hosts.

Comments. The weak areola superimposed on a rugose propodeum is diagnostic for this species; although P. dixianus is similar in this respect, the two are not easily confused since P.masoni has an evenly sclerotized hypopygium and mostly unsculptured (or weakly sculptured) third metasomal tergite. Some individuals with an indistinct areola may be difficult to separate from P. variabilis (with which it sometimes co­occurs on the same host species), but P. masoni has a much more strongly rugose propodeum, evenly sclerotized hypopygium in the female and a (usually) narrower first metasomal tergite. In addition, sternites 3–6 in the female show no anterior medial notching or splitting, but this is visible only by means of dissection in most cases.

This species is referred to as Pholetesor sp. 2 in Whitfield & Wagner (1988) and Gates et al. (2002).

Figures

FIGURES 17–21. Forewings of: 17, Pholetesor bucculatricis (Muesebeck); 18, P. zelleriae Whitfield; 19, P. masoni Whitfield; 20, P. dixianus Whitfield; 21, P. pinifoliellae Whitfield.

FIGURES 33–38. 33: metanotum of Pholetesor bucculatricis (Muesebeck), showing slight retraction from scutellum; 34: metanotum of P. salalicus (Mason), showing strong retraction from scutellum. Both FIGURES 400x. 35: propodeum and anterior metasomal tergites of P. bucculatricis (Muesebeck), dorsal view, 97.5x. 36: propodeum and anterior metasomal tergites of P. masoni Whitfield, dorsal view. 120x. 37: propodeum and anterior metasomal tergites of P. bedelliae (Viereck), dorsal view, 120x. 38: propodeum and anterior metasomal tergites of P. salalicus (Mason), dorsal view, 120x.

FIGURES 39–59. Anterior metasomal tergites, dorsal view, of: 39, Pholetesor masneri (Mason); 40, P. bucculatricis (Muesebeck); 41, P. zelleriae Whitfield; 42, P. masoni Whitfield; 43, P. dixianus Whitfield; 44, P. pinifoliellae Whitfield; 45, Pholetesor rhygoplitoides Whitfield; 46, P. bedelliae (Viereck); 47, P. chiricahuensis Whitfield; 48, P. longicoxis Whitfield; 49, P. powelli Whitfield; 50, P. thuiellae Whitfield; 51, P. rohweri (Muesebeck); 52, P. variabilis Whitfield; 53, P. viminetorum (Wesmael); 54, P. caloptiliae Whitfield; 55, Pholetesor ornigis (Weed); 56, P. salalicus (Mason); 57, P. salicifoliellae (Mason); 58, Pholetesor circumscriptus (Nees); 59, P. pedias (Nixon).

FIGURES 60–71. 60–62, Ovipositor apparati, lateral view, of: 60, Pholetesor bucculatricis (Muesebeck); 61, P. zelleriae Whitfield; 62, P. masoni Whitfield. 63–65: Apex of female metasoma, lateral view, of: 63, P. dixianus Whitfield; 64, P. pinifoliellae Whitfield; 65, P. rhygoplitoides Whitfield. 66: Ovipositor apparatus, lateral view, of P. bedelliae (Viereck). 67, 68: Apex of female metasoma, lateral view, of: 67, P. chiricahuensis Whitfield; 68, P. longicoxis Whitfield. 69: Ovipositor apparatus, lateral view, of P. powelli Whitfield. 70, 71: Apex of female metasoma, lateral view, of: 70, P. thuiellae Whitfield; 71, P. rohweri (Muesebeck).

FIGURES 79–86. Male genitalia, ventral view, of: 79, Pholetesor zelleriae Whitfield; 80, P. masoni Whitfield; 81, P. bedelliae (Viereck); 82, P. variabilis Whitfield; 83, P. viminetorum (Wesmael); 84, P. ornigis (Weed); 85, Pholetesor salalicus (Mason); 86, P. salicifoliellae (Mason).