Pholetesor ornigis (Weed)

Whitfield, James B., 2006, Revision of the Nearctic species of the genus Pholetesor Mason (Hymenoptera: Braconidae), Zootaxa 1144 (1), pp. 1-94 : 63-68

Pholetesor ornigis (Weed)

( figs. 14 , 28 , 55 , 75 , 84 )

Microgaster robiniae Fitch, 1859 (1858) . Trans. N.Y. State Agric. Soc. 18: 836. Holotype female, USNM no. 1814 (examined). Application to International Commission of Zoological Nomenclature ( Whitfield, 1986, Bull. Zool. Nomencl. 43: 96–98) resulted in conservation of ornigis (Weed) as the valid name (Bull. Zool. Nomencl. 44).

Apanteles ornigis Weed, 1887 . Bull. Ill. State Lab. Nat. Hist. 3: 6. Lectotype in Illinois Natural History Survey, designated by Frison (1927, Ill. State Nat. Hist. Surv. Bull. 16: 137–309) (examined). Designated type species of Pholetesor Mason by Mason, 1981, Mem. Entomol. Soc. Can. 115.

Protapanteles tortricis Ashmead, 1898 (1897) . Proc. Entomol. Soc. Wash. 4: 163. Holotype female, USNM no. 12798 (examined). Synonymized by Muesebeck, 1920, Proc. U.S. Nat. Mus. 58: 483–576.

Apanteles (Apanteles) braunae Viereck, 1912 . Proc. U.S. Nat. Mus. 42: 614. Holotype male, USNM no. 14701 (examined). Synonymized by Muesebeck, 1920, Proc. U.S. Nat. Mus. 58: 483–576.

Apanteles (Apanteles) lithocolletidis Viereck, 1912 , Proc. U.S. Nat. Mus. 42: 615. Holotype male, USNM no. 14704 (examined). Synonymized by Muesebeck, 1920, Proc. U.S. Nat. Mus. 58: 483–576.

Females. Body length 1.5–2.4 mm, forewing length 1.8–2.4 mm.

Head. Frons. 1.3–1.4x broader at midheight than medially long, distinctly but not deeply punctate; inner margins of eyes weakly converging towards clypeus. Antennae dark brown, slightly longer than body in dried specimens; junction between pedicel and flagellum lighter in color; all but distal 4–6 flagellomeres with 2 ranks of placodes; flagellomere 2 3.7–3.8x as long as broad; flagellomere 14 1.6–1.8x as long as broad. Palpi light yellow­brown throughout. Head in dorsal view approximately 2.0x as broad as medially long.

Mesosoma . Mesoscutum in dorsal view slightly broader than head, shallowly punctate anteriorly to virtually impunctate posteriorly; microsculpture producing dull, satinymetallic sheen between punctures. Pronotal furrow weakly crenulate. Scutoscutellar scrobe fine, narrow, arched slightly medially, not set in depression. Scutellar disc sculptured as posterior region of mesoscutum, slightly longer than anteriorly broad. Metanotum strongly retracted from scutellum, exposing mesothoracic postphragma, broadly excavated mesad sublateral setiferous projections; transverse carinae at about midlength usually weakly developed but distinct. Propodeum 1.7–1.8x broader than long at longest point, generally weakly rugulose with strong, irregular ridging radiating from nucha; sometimes with hints of weak costulae and/or transverse sculpturing anteromedially; posterolateral corners weakly to strongly sunken.

Legs. Prothoracic legs light yellow­brown except darker brown coxae and distal tarsomeres. Mesothoracic legs similarly colored except entire tarsi usually darker brown. Metathoracic coxae usually dark brown (sometimes lighter at distal end); trochanters and femora light yellow­brown except infuscate spot dorsally near distal ends of femora; tibiae and tarsi mostly infuscate yellow­brown except proximal portions of tibiae. Spines on outer faces of hind tibiae about 30 in number, irregularly scattered, whitish, all of one kind. Inner apical spurs of hind tibiae 1.2–1.4x as long as outer, nearly half as long as hind basitarsi.

Wings. Tegulae light yellow­brown, translucent. C+Sc+R, stigma, R1, 2r, 1Rs and 2M of forewing brown, strongly pigmented; other venation pale brown to colorless. 2r and 1Rs variable in relative lengths, usually more or less equal to 2r to slightly longer, meeting at distinct to slightly rounded 150­degree angle. R1 longer than stigma, 3–5x longer than distance from distal end of R1 to end of 3Rs fold along wing edge. Hindwings with only vein 1R1 strongly pigmented; all other venation colorless or pale. Cu+cu­a (nervellus) nearly straight, weakly reclivous, vannal lobe weakly flattened subapically, evenly fringed with short hairs.

Metasoma. Tergite I rugose, parallel­sided to weakly broadening or narrowing posteriorly, usually very weakly rounded posterolaterally, 1.5–1.8x longer than posteriorly broad; anteromedial depression broad, smoother with concentric sculpturing. Tergite II sculptured as on I, 1.9–2.1x as broad posteriorly as medially long and 1.3–1.7x as broad as posterior breadth of tergite I; length subequal with that of third tergum; posterior margin marked by straight, irregularly crenulate furrow; anterolateral corners broadly rounded. Tergum III anteromedially roughened over variable area, unmarked by strong sculpturing over remaining surface. Laterotergites usually intermediate in color between that of hind tibiae and hind femora. Succeeding terga unsculptured, unmodified, overlapping. Hypopygium longer than hind basitarsi, evenly pigmented and sclerotized to medial ventral fold; apex in lateral view not strongly acuminate, forming about a 55–60­degree angle. Ovipositor sheaths longer than hind basitarsi (usually subequal with hypopygium), weakly decurved over expanded distal portions (ventral edge nearly straight), evenly and gradually broadening past narrow, decurved petioles to near distal tip; tip appearing asymmetrically beveled/pointed due to apical brush of hairs; expanded distal portions hairy nearly throughout but more densely so apically. Ovipositor evenly decurved, exserted but not usually by distance longer than length of sheaths.

Males. Body length 1.5–2.2 mm, forewing length 1.8–2.4 mm. Antennae longer, darker and more slender than in females, all flagellomeres except distal 3 with 2 ranks of placodes; flagellomere 14 2.1–2.3x as long as broad. Prothoracic legs light as in female; mesothoracic femora (often metathoracic as well) mostly much darker than in female. Tegulae darker than in female, sometimes dark brown. Forewing venation tending to be slightly darker and more grey­brown. First metasomal tergite narrower than in female, usually weakly narrowing posteriorly. Second tergite less transverse, more strongly triangular, than in female. Third tergum with little or no sculpturing. Laterotergites usually moderate brown, occasionally very dark.

Variation. This species and P. bedelliae are the most commonly encountered species of Pholetesor in the eastern U.S. and Canada. As a result, series are available from a large number of hosts and localities. A considerable amount of variability exists among these series; a few especially variable features will be mentioned.

Body size appears to be largely a function of the size of the host larva from which the wasp emerged. P. ornigis attacks a wide range of blotchmining Lepidoptera , from small Phyllonorycter and Tischeria to some larger Cameraria and Caloptilia species. Among the smallest individuals (usually well under 2 mm) are those reared from Cameraria sp. on Carpinus , Phyllonorycter celtisella on Celtis occidentalis , and from Phyllonorycter and Leucanthiza on Amphicarpa bracteata . The largest (often 2.2–2.4 mm) often emerge from Cameraria aceriella on Acer and several Cameraria spp. on various oaks.

A number of other characters seem to covary with size. Larger individuals tend to have proportionately broader anterior metasomal tergites, stronger mesoscutal punctation, brighter legs coloration and longer ovipositor sheaths. These correlations are by no means absolute, and may be also influenced by such factors as seasonality (especially temperature and humidity differences), geography and host physiology.

A few variations are restricted to single, or a few, reared series, and may indicate genetic isolation or differentiation. For example, specimens reared from Cameraria on white oak in eastern Canada have unusually broad first metasomal tergites in both sexes, a short R1, and almost completely infuscate hind femora, even in the females.

As in other ornigis ­group species, males are more variable in coloration and metasomal tergite shape than females, and individual unreared specimens are often extremely difficult to separate from males of P. salalicus and P. salicifoliellae .

Final instar larva. Labium with 6–7 pairs of setae; maxillae each with 2 long setae; mandibles set with 16–17 long teeth (not counting bifid tip).

Cocoons. White, smooth, elongate­oval, capsule­like, almost always with a more translucent band centrally, suspended hammock­like within the host mine or shelter.

Material examined. Reared from Acrocercops onosmodiella (Busck) : 12 males, ONTARIO, June. Reared from Cameraria aceriella (Clemens) : 32 females, 28 males, PENNSYLVANIA, ONTARIO, May, September (also Feb.–March from overwintering cocoons). Reared from C. corylisella (Chambers) : 7 females, 1 male, ONTARIO, March (from held overwintering cocoons). Reared from C. guttifinitella (Clemens) on Rhus toxicodendron : 16 females, 19 males, ONTARIO, QUEBEC, May, July, August. Reared from C. hamadryadella (Clemens) on Quercus alba , Q. macrocarpa : 22 females, 13 males, ONTARIO, July, August. Reared from C. ostryarella (Chambers) on Ostrya : 11 females, 8 males, ONTARIO, QUEBEC, August, January–March (from held overwintering coccons). Reared from Leucanthiza amphicarpaefoliella Clemens : 5 females, QUEBEC, July. Reared from " Lithocolletis " sp. on Amphicarpa : 2 males, QUEBEC, July, August. Reared from " Lithocolletis " sp. on Carpinus : 2 females, 1 male, ONTARIO, May. Reared from " Lithocolletis " sp. on sweet fern ( Comptonia peregrina ): 2 females, ONTARIO, adults January from held overwintering cocoons. Reared from " Lithocolletis " sp. on Hamamelis: 3 females, ONTARIO, May. Reared from " Lithocolletis " sp. on Ostrya : 1 female, 5 males, ONTARIO, QUEBEC, July, August. Reared from " Lithocolletis " spp. on Quercus spp. (mostly white oak group): 31 females, 15 males, MANITOBA, NOVA SCOTIA, ONTARIO, QUEBEC, July, August, March (from held overwintering cocoons). Reared from " Lithocolletis " sp. on Ulmus americana : 5 females, 1 male, NOVA SCOTIA, August–September. Reared from Paraclemensia acerifoliella (Fitch) : 5 females, 5 males, ONTARIO, June, July. Reared from Parornix conspicuella (Dietz) on Betula populifolia : 1 female, 1 male, CONNECTICUT, September. Reared from Parornix geminatella (Packard) on Malus : 36 females, 12 males, ARKANSAS, PENNSYLVANIA, WISCONSIN, July–October. Reared from Parornix sp. on Prunus virginiana : 3 females, 3 males, NEW YORK, August. Reared from Phyllonorcyter blancardella (Fabricius) on Malus : 4 females, 8 males, MASSACHUSETTS, ONTARIO, July–November. Reared from P. celtisella (Chambers) on Celtis occidentalis : 27 females, 35 males, ONTARIO, July, August. Reared from P. clemensella (Chambers) : 2 males, ONTARIO, October–November. Reared from P. crataegella (Clemens) : 1 female, 4 males, ONTARIO, QUEBEC, May, June. Reared from P. diversella (Braun) : 1 male, NOVA SCOTIA, May. Reared from P. emberizaepenella (Bouche) on Lonicera bella : 3 females, 3 males, ONTARIO, October, November. Reared from P. lucetiella (Clemens) : 1 female, VIRGINIA, July. Reared from P. lucidicostella (Clemens) : 7 females, 5 males, ONTARIO, adults February, March from held overwintering cocoons. Reared from P. malimalifoliella (Braun) on Malu s: 46 females, 26 males, NOVA SCOTIA, ONTARIO, QUEBEC, WISCONSIN, July–October. Reared from P. ostryafoliella (Clemens) on Ostrya : 3 females, QUEBEC, September. Reared from P. propinqinella (Braun) : 11 females, 14 males, DISTRICT of COLUMBIA, NOVA SCOTIA, ONTARIO, VIRGINIA, May–June, August, October–November (overwintering generation). Reared from P. robiniella (Clemens) : 11 females, 4 males, NEW HAMPSHIRE, NEW YORK, ONTARIO, WEST VIRGINIA, July, September, February (from overwintering cocoons). Reared from Phyllonorycter sp. on Acer rubrum : 2 females, NEW YORK, NORTH CAROLINA, July, August. Reared from Phyllonorycter sp. on Lonicera : 10 females, 4 males, NEW YORK, ONTARIO, May, July, August. Reared from Phyllonorycter sp. on Malus : 75 females, 88 males, NOVA SCOTIA, ONTARIO, QUEBEC, VERMONT, May–September. Reared from Phyllonorcyter spp. on Prunus spp. : 6 females, 8 males, NOVA SCOTIA, ONTARIO, July–September. Reared from Phyllonorycter sp. on Tilia americana : 14 females, 3 males, ONTARIO, QUEBEC, May, July, August. Reared from Tischeria sp. on Quercus falcata : 1 female, 2 males, TEXAS, November (emerged February indoors). Reared from "gracillariid" on Vaccinium : 1 male, NOVA SCOTIA, August. Reared from "tentiform leafminers" (probably Parornix or Phyllonorycter ) on Malus : 18 females, 10 males, NEW YORK, NOVA SCOTIA, ONTARIO, QUEBEC, May–August. Reared from undetermined leafminers on Aesculus : 2 females, 1 male, KENTUCKY, August. Reared from undetermined leafminers on Quercus spp. : 21 females, 20 males, MINNESOTA, VIRGINIA, May, July, August .

Not reared or properly associated: 226 females, 144 males, more or less throughout northeastern North America west to Oregon , south in eastern U.S. to Georgia , in west to Arizona but apparently not into California.

Hosts. The above list under "Material Examined" needs no repeating; in addition, Whitfield and Wagner (1988) provide a detailed account of the host range of this species. Pholetesor ornigis clearly attacks a wide range of blotchminers, especially Gracillariidae , on deciduous trees, shrubs, vines, etc., throughout much of North America. It appears to be displaced from, or to not attack, the common hosts of P. caloptiliae and P. salicifoliellae , i.e., several large species of Caloptilia on Rhus and Cornus and a number of blotchminers on Salix , Populus and Alnus . Pholetesor ornigis and P. salicifoliellae apparently co­occur at some localities on Phyllonorycter spp. on Lonicera .

Comments. Pholetesor ornigis and the other ornigis ­group members form a tight complex of species in North America. When the Palearctic species are included, the group becomes even more difficult taxonomically. Pholetesor nanus (Reinhard) is particularly difficult to separate from ornigis on morphological grounds. The two may be conspecific, but there appear to be differences in the host spectrum. Pholetesor nanus apparently

attacks mostly blotchminers on Salix , Alnus , and Betula —almost exactly matching the hosts ornigis does not attack in North America. Pholetesor nanus is largely, or entirely, thelytokous in England ( Shaw and Askew, 1976), but apparently this is not entirely universal within mainland European populations and I am not inclined to weight this too highly, especially in light of the situation with the importation of P. pedias (see under that species).

Figures

FIGURES 9–16. Cocoons of Pholetesor. 9: P. bedelliae (Viereck), on underside of leaf with Bedellia mine. 10: Cocoon of Bucculatrix albertiella on leaf of Quercus agrifolia; cocoon of P. bucculatricis (Muesebeck) is spun inside this cigar­shaped host cocoon. 11: P. salalicus (Mason) cocoon inside opened mine of Cameraria nemoris on Vaccinium ovatum. 12: P. salalicus cocoon inside opened mine of Cameraria gaultheriella on Gaultheria shallon. 13: Cocoon of P. caloptiliae Whitfield. 14: Cocoon of P. ornigis (Weed). 15: Cocoons of P. salalicus, showing varraiation in banding pattern. 16: Cocoon of P. salicifoliellae (Mason).

FIGURES 27–32. Forewings of: 27, Pholetesor caloptiliae Whitfield; 28, P. ornigis (Weed); 29, P. salalicus (Mason); 30, P. salicifoliellae (Mason); 31, P. circumscriptus (Nees); 32, P. pedias (Nixon).

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).