Pholetesor variabilis, Whitfield, 2006

Whitfield, James B., 2006, Revision of the Nearctic species of the genus Pholetesor Mason (Hymenoptera: Braconidae), Zootaxa 1144 (1), pp. 1-94 : 51-55

Pholetesor variabilis , new species

( figs. 25 , 52 , 72 , 82 )

Holotype female. Body length 1.9 mm, forewing length 2.2 mm.

Head. Frons 1.3–1.5x broader at midheight than medially long, weakly punctate, with only faint suggestions of metallic luster; inner margins of eyes weakly converging towards clypeus. Postgenae, vertex and occiput weakly, shallowly punctate, with faint, dull metallic sheen. Antennae very dark brown throughout, somewhat stout, about as long as forewing, with all but distal 4–5 flagellomeres with 2 ranks of placodes; flagellomere 2 3.1x longer than wide; flagellomere 14 1.3x longer than wide. Palpi pale yellow­brown, proximally darker. Head in dorsal view about 1.9x broader than medially long.

Mesosoma . Mesoscutum shallowly and closely but distinctly punctate anteriorly, becoming more weakly so posteriorly near scutellum; surface otherwise slightly dull with little sign of metallic sheen; width just anterior to tegulae just slightly less than that of head. Pronotal furrow deep, indistinctly crenulate. Scutoscutellar scrobe nearly straight medially, composed of about a dozen sharp, fine crenulations. Scutellar disc with shallow punctation, more widely spaced than on most of mesoscutum, somewhat shinier between punctures than mesoscutum, slightly longer than posteriorly broad. Metanotum weakly excavated anteriorly mesad sublateral setiferous projections, sometimes with shallow anterior indentations giving impression of stronger anterior retraction from scutellum, with transverse carinae on either side at about 1/3 of length and parallel to anterior edge, setting off transverse depressions that are crossed by 3 short carinulae. Propodeum finely, irregularly rugulose with superimposed small ridges radiating from nucha; width approximately 2x maximum length.

Legs. Front coxae, trochanters and proximal 0.3 (dorsally 0.7) of femora dark brown to black; remainder of legs fulvous with slightly infuscate tarsi. Middle legs of similar coloration except apical 0.3–0.4 of tibiae infuscate, tarsi more strongly darkened. Hind coxae, proximal trochanters dark brown to black; distal trochanters and femora infuscate yellow­brown; tibiae light yellow­brown over proximal 0.7, distal portions and tarsi dark brown. Spines on outer faces of hind tibiae about 25 in number, some difficult to distinguish from normal hairs. Inner hind tibial spurs slightly longer than outer, pale yellowish, about 1/3 as long as hind basitarsi.

Wings. Tegulae dark brown. Forewing venation pigmented dark brownish except paler proximal regions; stigma, C+Sc+R, R1, 2r and 1Rs most strongly pigmented. R1 slightly longer than stigma, about 3x as long as distance from its tip to end of 3Rs fold along wing edge; 2r slightly arched, subequal in length with 1Rs and meeting it at a distinct, approximately 125­degree angle. Stigma about 2.6x longer than broad, posterior edges nearly straight. Hindwing with vannal lobe nearly evenly convex, with even fringe of short hairs over distal 0.6 (proximally and at extreme distal end with longer fringe); Cu+cu­a of hindwing strongly reclivous, weakly arched.

Metasoma. Tergite I broadening posteriorly to a strongly rounded apex, slightly broader at widest point than long, broadly excavated anteromedially to about 0.3 of length; surface mostly strongly rugose. Tergite II subquadrate, 2.5x broader than long, slightly broader posteriorly; anterolateral corners somewhat irregularly sculptured and poorly defined; coarsely rugose throughout with weak medial longitudinal ridge. Tergum III subequal in length withII, anteriorly and medially finely sculptured. Laterotergites deep brown, nearly hidden in dorsal view. Hypopygium subequal in length with hind basitarsus, with weak submedial crease on either side; medial section hairless, more translucent and flexible but not multiply creased; tip of hypopygium bluntly acuminate. Ovipositor sheaths shorter than hind basitarsi, straight and with fusiform, expanded hairy distal 0.75 (very similar to those of P. bedelliae ). Ovipositor moderately decurved.

Males. Leg coloration darker, with more extensive darkened portions of femora and tibiae; tergite I of metasoma narrower than in females, sometimes longer than broad; tergite III less extensively sculptured than in females. Antennae clearly longer than forewings, with more slender apical flagellomeres (flagellomere 14 2.0–2.3x longer than broad); all but distal 3 flagellomeres with 2 ranks of placodes. Inner margins of eyes more strongly convergent than in females. Sometimes with nearly colorless M+Cu, 1M, 1Rs+M of forewing (when from Salix leafminers). Size not tending to be strongly different from females. Genitalia shown in figure 82 .

Variation. Body length 1.6–2.2 mm, forewing length 1.9–2.3 mm. Variation exists in the breadth of the first metasomal tergite; some of the male specimens with narrower tergites can possibly be confused with males of P. bedelliae , although females of the two species tend to be more easily distinguished. A narrow, weak posteromedial depression is present on the first tergite in some individuals. The third tergum ranges from almost completely sculptured (at least medially) to virtually sculptureless except along the extreme anterior edge. A few specimens have the ovipositor sheaths as long as the hind basitarsus and/or a longer metacarp than does the type.

The specimens from leafminers on Salix and Populus are extremely similar to those from Bucculatrix spp. on various plants, despite the seeming contrast in host biologies. I have been unable to find consistent differences between the individuals from these hosts, so I have considered them conspecific until conflicting evidence arises.

Final instar larva. Labium with 1 pair of setae on short tubercles; maxillae each with 1 seta; mandibles set with 9–11 long teeth (not counting bifid tip).

Cocoons. On Bucculatrix spp. , a delicate cocoon is spun as a liner within that of the host, so that its external appearance is not readily observed. I have not seen cocoons from the specimens attacking eastern gracillariids on Salix , but suspect the cocoon is similar to that of P. bedelliae . On a few occasions, I have found bedelliae ­group type cocoons in Phyllonorycter mines on Salix , but have only reared (in the western U.S.) specimens I would assign to P. bedelliae from them.

Material examined. Holotype female: CALIFORNIA. Contra Costa Co., Tilden Regional Park, 20­VI­1981 (J.B. Whitfield). Paratypes: CALIFORNIA Alameda Co., Berkeley, 4 females, 7 males, 3/ 5­III­1983, ex Bucculatrix on Baccharis pilularis, JBW no. 83C2 (J.B. Whitfield, D.L. Wagner), 2 males, 10­IV­1983, ex Bucculatrix on Baccharis, JBW no. 83D19 (JBW), 1 female, 25­V­1983, ex Bucculatrix on Baccharis (JBW) . Contra Costa Co., Tilden Reg. Pk, 2 males, 13­VI­1983, ex Bucculatrix on Baccharis, JBW no. 83F30 (JBW), 13 females, 1 male, 15­VIII­1983 (JBW), 14 females, 11 males, 25­VI­1983 (JBW).

Holotype, from JBW collection, deposited in USNM, paratypes in USNM, CNC, CAS, University of California, Berkeley , collections.

Other material: ALBERTA. Paddle Prairie, 2 females, 22­VII­1964, ex Lyonetia (Forest Insect Survey) . BRITISH COLUMBIA. Penticton, 2 females, 6/ 8­VIII­1967 (J. R. Vockeroth). CALIFORNIA. Alameda Co., Berkeley Hills, 4 females, 1 male, 11­IV­1981, ex Bucculatrix albertiella, JBW no. 81D8 ( JBW), 1 male, 7­VIII­1982 ( JBW), 1 female, 13­VIII­1983 ( JBW). Patternson Reserve , Del Valle Lake , 1 female, 2 males, 9­III­1974, ex Bucculatrix variabilis, JAP no. 74C2 (J.A. Powell). Strawberry Canyon, 2 females, 11­ IV­1968, ex Bucculatrix albertiella, JAP no. 68D117/8 (P.Opler). Alpine Co. , nr. jct. 4 & 89, 2 females, 9­VII­1983 ( JBW, DLW). Contra Costa Co. , 2 mi. E. Antoich, 1 male, ex Bucculatrix albertiella on Quercus agrifolia, JAP no. 68D55 (P.Opler). Lafayette, 1 female, 6­VII­1956 ( R. A. Stirton), 1 female, 20­V­1983 ( JBW). Moraga, 1 female, 2 males, 21­VII­1977 (D.G. Denning). E. Mt. Diablo , nr. Clayton, 8 females, 20 males, 27­ II­1982, ex Bucculatrix on Baccharis pilularis (DLW, JBW) . Redwood Regional Park, 1 male, 28­VIII­1968, ex upperside blotches on Dirca occidentalis (P.Opler) . Tilden Regional Park, 3 males, 29­IV­1981 ( JBW), 1 female, 22­VII­1982 ( JBW), 1 male, 29­ VIII­1982 ( JBW), 7 females, 10 males, 18­III­1984, ex Bucculatrix on Baccharis pilularis, JBW no. 84C34 ( JBW). El Dorado Co. , Fallen Leaf Lake , 3 females, 3/ 4­VII­1983, ex Bucculatrix on Artemisia tridentata (DLW) . Kern Co. , Belridge, 1 female, 20­VI­1979 (D.B. Wahl). Los Angeles Co. , Santa Catalina Id., Middle Canyon, 250' el., 1 male, 2­V­ 1978, ex Aristotelia on Salix lasiolepis, JAP no. 78E11 (J.A. Powell). Marin Co. , Lily Lake / Alpine Lake , 1 male, 14­IV­1979, ex Bucculatrix sp. , JAP no. 79D4 (J.A. Powell). Mendocino Co. , Hopland, U.C. Field Sta., 1 male, 4­IX­1976, ex Quercus lobata leafminers (D.S. Green). Riverside Co. , Riverside, 1 male, IV­1948, ex Bucculatrix coccon on Artemisia californica (P.H. Timberlake) . San Benito Co. , Rock Gulch, 1 male, 10­V­ 1977, ex B. albertiella on Q. agrifolia, JAP no. 77E79 (D.S. Green). San Diego Co. , La Jolla, 1 female, 18­II­1984, ex Bucculatrix on Malacothamnus, JAP no. 84B60 (D.L Wagner). San Diego, 1 male, 27­I­1975 (L. Hawkins). San Lius Obispo Co. , 5 mi. SE Cambria, 1 male, 28­III­1984, ex Bucculatrix on Q. agrifolia, JAP no. 84C47 ( DLW). San Mateo Co. , Woodside, 1 female, 10­V­1977, ex B. albertiella on Q. agrifolia, JAP No. 77E102 (D.S. Green). Santa Clara Co. , Stanford Univ., 1 female, 9­V­1952 (P. Arnaud). Santa Cruz Co. , Santa Cruz, 2 females, 10­V­1977, ex leafminers (probably Bucculatrix ) on Q. agrifolia (D.S. Green) . Nr. Felton, 1 male, 31­VII­1982, ex Bucculatrix (from live oak?) ( JBW). Siskiyou Co. , 1 mi. S. Castella, 2 females, 1 male, 17­IX­1982, ex Bucculatrix on Quercus garryana, JAP no. 82J122/3 (D.L. Wagner). Tulelake, 1 female, 12­VIII­1977, black light trap ( T. R. Haig). Solano Co. , Cold Creek , nr. Monticello Dam, 1 male, 18­V­1975 ( R. W. Brooks). Fairfield, 1 male, 20­IX­1955 ( R. M. Bohart). Sonoma Co. , Sebastopol, 1 female, 1­II­1933, ex Bucculatrix variabilis (Keifer) . Sutter Co. , Feather River nr. Nicolaus, 1 male, 4­X­1982, ex Bucculatrix on Artemisia douglasiana (JBW, DLW) , 1 male, 1­IX­1981, ex Paraleucoptera on Populus fremontii, JAP no., 81J2 ( DLW). Live Oak Park, 1 female, 1 male, 24­V­1944 (no collector given). Yolo Co. , Davis, 1 female, 6­X­1961 (M.E. Irwin), 1 female, 27­IV­1959 (F.E. Strong), 1 female, 15­X­ 1952 (J.C. Hall). Putah Creek , 9 mi. W. Winters, 3 females, 2 males, 19­V­1968, ex Cameraria (?) on Salix, JAP no. 68E28 (P. Opler). 4 mi. NE Rumsey, 1 female, 3­VI­1960 ( R. O. Schuster). COLORADO. Doolittle Ranch, Mt Evans , 9800' el., 1 male, 9­VII­1961 (S.M. Clark), 1 female, 4­VIII­1961 (S.M. Clark). IDAHO. Ada Co. , 10 mi. NE Kuna, 1 female, 11­VII­1952, on Phacelia (W.F Barr) . Boise, 1 male, 22­V­1961, on Purshia tridentata (M.M. Furniss) . Craters of the Moon Nat. Mon., Little Cottonwood Creek , 1 female, 23­VI­1965 (D.S. Horning). Lewiston Hill, 1 male, 3­V­1925 (A.L. Melander). Nez Perce Co. , 4 mi. S. Lewiston, 1 female, 5­X­1978 (B. Sullivan). MICHIGAN. Mackinac Co. , 1 male, 4­VI­1959 ( R. & K. Dreisbach). Osceola Co. , 1 female, 14­VI­ 1952 ( R. R. Dreisbach). NEVADA. Elko Co. , 10 mi. W. Carlin, 1 female, 6­VII­1956 ( T. R. Haig). ONTARIO. Barrow Bay , 2 females, 4 males, 17­VII­1952, ex Lithocolletis tremuloidella (Forest Insect Survey) . Christian Island , 1 female, 3 males, 16­VII­1952, ex L. tremuloidella (FIS) . Clear Lake , 1 female, 2 males, 24­VII­1952, ex L. tremuloidella (FIS) . Fort Frances , 1 female, 26­VII­1947, ex L. tremuloidella (FIS) . Fort Hope , 1 female, 21­VIII­1950, ex " Gracillariidae " ( FIS). Franz, 1 female, 1 male, 28­VII­1962, ex Lithocolletis salicifoliella (FIS) . Hearst, 3 females, 3 males, 3­9­VIII­1971, ex Micrurapteryx on Salix (FIS) , 3 females, 3 males, 3­VIII­1972, ex Micrurapteryx on Salix (FIS) . Hornepayne, 2 females, 1 male, 2­VIII­1979, ex Micrurapteryx on Salix (FIS) . Longlac, 3 females, 2 males, 28­VII­1975, ex Micrurapteryx on Salix (FIS) . Ralphton, 2 females, 11­VIII­1952, ex Lithocolletis tremuloidella (FIS) . Redvers Twp., 2 femels, 3 males, 24­VII­6­VIII­1946, ex L. tremuloidella (FIS) . Southworth Twp., 1 female, 1 male, 29­VII­7­VIII­1946, ex L. tremuloidella (FIS) . Wabanash L., 1 female, 2 males, 27­VII­ 1944, ex Lithocolletis sp. ( FIS). Zealand, 1 female, (?)­1946, ex L. tremuloidella (FIS) . Locality uncertain, 5 females, 2 males, no dates, ex L. tremuloidella (FIS) . OREGON. Lake Co. , 24 mi. SE La Pine, 1 male, 12­VII­1957 (G.F. Kraft). SASKATCHEWAN. Ceylon, 1 male, 4­VIII­1977, swept ex Artemisia biennis (G. Kelley) . Elfros, 1 female, 27­ VII­1977, swept ex Artemisia biennis (M.G. Maw) . La Ronge, 1 female, VII­1977 (N.L.H. Krauss). UTAH. Provo, 1 female, 20­VIII­1962 (N.M. Jorgensen) .

Hosts. Bucculatrix albertiella Busck on Quercus agrifolia Nee , B. variabilis Braun and B. separabilis Braun on Baccharis pilularis DC , various undetermined Bucculatrix spp. on Artemisia californica Bess. , A. douglasiana Bess. , A. tridentata Nutt. and Quercus garryana Douglas ; Paraleucoptera albella on Populus fremontii Wats. , Phyllonorycter spp. on Populus and Salix spp. , and Micrurapteryx salicifoliella (Chambers) on Salix sp.

Comments. In virtually all features except width of the first metasomal tergite, length of the second tergite and (in part) choice of hosts, P. variabilis is extremely similar to P. bedelliae . I am not at all certain that all of the individuals I have placed under this name are conspecific, as the host range is fairly broad both ecologically and taxonomically. However, the same situation appears to be true for P. bedelliae (in fact, involving some of the same host and plant genera). Despite the parallels in the two species, the constancy of the morphological differences between the two species across a wide range of hosts impels me to regard the two as separate taxa. In addition, these differences hold up even when, in rare cases, the two attack the same host at the same locality.

This species is referred to as Pholetesor species 4 in Whitfield & Wagner (1988).

Figures

FIGURES 22–26. Forewings of: 22, Pholetesor rhygoplitoides Whitfield; 23, P. bedelliae (Viereck); 24, P. powelli Whitfield; 25, P. variabilis Whitfield; 26, P.viminetorum(Wesmael).

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 72–78. Ovipositor apparati, lateral view, of: 72, Pholetesor variabilis Whitfield; 73, P. viminetorum (Wesmael); 74, P. caloptiliae Whitfield; 75, P. ornigis (Weed); 76, P. salalicus (Mason); 77, Pholetesor salicifoliellae (Mason); 78, P. pedias (Nixon).

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).