Pholetesor salicifoliellae (Mason)

Whitfield, James B., 2006, Revision of the Nearctic species of the genus Pholetesor Mason (Hymenoptera: Braconidae), Zootaxa 1144 (1), pp. 1-94 : 72-75

Pholetesor salicifoliellae (Mason)

( figs. 16 , 30 , 57 , 77 , 86 )

Apanteles salicifoliellae Mason. 1959 . Canad. Ent. 91: 43. Holotype female, CNC no. 669 &, examined.

Females. Body length 1.5–2.1 mm; forewing length 1.7–2.4 mm.

Head. Frons 1.3–1.4x as broad at midheight as medially long, distinctly but not deeply punctate, with faint metallic sheen. Antennae deep brown, barely longer than body; junction between pedicel and flagellum lighter in color; flagellomeres darker between placode bands; all but distal 5–6 flagellomeres with 2 ranks of placodes; flagellomere 2 3.2–3.6x as long as broad; flagellomere 14 1.5–1.9x as long as broad. Palpi light yellowbrown throughout. Lateral ocelli separated from anterior by just less than one ocellar diameter, from each other by about 2 ocellar diameters. Head in dorsal view about 2.0x broader than medially long.

Mesosoma . Mesoscutum.95 as broad as head, shallowly punctate anteriorly, becoming almost impunctate posteriorly near scrobe; microsculpture producing satiny/ metallic sheen. Pronotal furrow weakly crenulate. Propleuron distinctly punctate, hairy except anteriorly near head. Scutoscutellar scrobe sharp, fine, slightly arched medially. Scutellar disc faintly punctate (as posterior portion of mesoscutum), 1.21.3x as long as anteriorly broad. Scutellar lunules moderately broad, semicircular; axillary troughs distinctly crenulate. Mesopleural furrow shallow, broad, smooth, met at midlength by distinct but weak impressed line running dorsally. Metanotum strongly retracted from scutellum, broadly exposing mesothoracic postphragma; anterior margin broadly excavated mesad sublateral setiferous projections; transverse carinae at midlength on either side weakly to moderately developed. Metapleuron smooth, hairless anteriorly to just beyond spiracle, then somewhat raised, punctate, hairy, becoming less strongly so posteriorly. Propodeum 1.8–1.9x broader than long at longest point, often with weak transverse ridging posterolaterally; anterolaterally weakly rugulose; nucha giving rise to anteriorly diverging ridges which break down into more or less transverse sculpturing anteromedially.

Legs. Prothoracic legs light yellow­brown except darkened coxae and apical tarsomeres. Mesothoracic legs similar except darkened femoral bases and tibial apices. Metathoracic coxae dark brown except lighter ventrally at distal end (rarely mostly light yellow­brown); trochanters and femora light yellow­brown with some infuscation dorsally, especially near femoral apices; tibiae and tarsi darker brown except tibial bases. Spines on outer faces of hind tibiae about 30 in number, irregularly scattered, all of one kind. Inner apical spur of hind tibia 1.2–1.4x as long as outer, about half as long as hind basitarsi or shorter.

Wings. Tegulae pale yellowish to medium brown, translucent. C+Sc+R, stigma, R1, 2r, lRs, 2M pigmented moderate grey­brown; other venation faintly pigmented to colorless. 2r and lRs subequal in length or 2r shorter, meeting at weak curved angle. R1 longer than stigma, 2–3x as long as distance from its distal end to end of 3Rs fold along wing edge. Vannal lobe of hindwing weakly flattened subapically, fringed evenly with moderatelength hairs. Cu+cu­a weakly arched, reclivous.

Metasoma. Tergite I mostly rugose, weakly to strongly narrowing posteriorly, 1.7– 2.0x as long as posteriorly broad; lateral margins arched, especially posteriorly; smoother in anteromedial excavation. Tergite II sculptured as in I to strongly longitudinally aciculate, 2.4–2.7x as broad posteriorly as medially long; posterior crenulate margin weakly concave; lateral margins slightly curved, meeting posterior furrow at about 50­ degree angle. Tergum III sometimes weakly roughened anteromedially, otherwise resembling more posterior terga in surface texture. Laterotergites medium brown, occasionally lighter—usually somewhat darker than hind femora. Hypopygium longer than hind basitarsi, evenly pigmented and sclerotized to medial ventral fold; extreme apex weakly acuminate and forming about a 60­degree angle in lateral view. Ovipositor sheaths in entirety slightly longer than hind basitarsi, evenly tapering broader (after narrow petiole) to a beveled/ pointed tip; expanded distal portions hairy virtually throughout. Ovipositor evenly and strongly decurved.

Males. Antennae longer than in female (clearly longer than body); all flagellomeres except apical 3 with 2 ranks of placodes; flagellomere 14 2.1–2.5x as long as broad. Axillary troughs often less distinctly crenulate than in females. Propodeum somewhat shinier, less strongly sculptured than in females. Prothoracic legs colored as in females; meso­ and metathoracic legs generally with femora darker than in females. Second metasomal tergite proportionately longer (posterior width 1.9–2.3x medial length), less strongly sculptured; third tergum usually sculptureless. Laterotergites usually much darker than in females. Genitalia shown in figure 86 .

Variation. Most of the obvious variation occurs in coloration and sculpturing of the metasomal tergites. Very occasionally in low elevation or southern series, the wing venation, legs and laterotergites become light in color as in salalicus , but even then the stigma is usually more greybrown. High elevation and extreme northern material (Alaska, etc.) tends to be very dark in leg, laterotergite and wing venation coloration and the sculpturing of the metasomal tergites is shinier, finer and much more longitudinal in trend. The Alaskan specimens are particularly extreme; at first glance, they appear to represent a separate species, but intermediates cause me to doubt this.

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

Cocoons. Whitish, elongate­oval, capsule­like, with translucent band medially covering.2–.3 of length; suspended by a thread from each end within the mine or shelter of the host.

Material examined. Reared from Acrocercops sp. on Prunus virginiana : 1 female

CALIFORNIA, July; from Caloptilia diversilobiella Opler on Rhus diversiloba : 7

females, 11 males, CALIFORNIA, May, August; from Caloptilia ferruginella (Braun) on Rhododendron occidentale : 1 female, 1 male, CALIFORNIA, October ;

from Caloptilia sp. on Acer macrophyllum . 2 females. 1 male. CALIFORNIA (Sierra), September; from Caloptilia sp. on Alnus tenuifolia : 1 male, CALIFORNIA,

September; from Caloptilia sp. on Salix : 2 females, CALIFORNIA, May;

from Cameraria sp. on Alnus oregona : 1 female, CALIFORNIA, July; from "elachistid" (no host given): 1 female, OREGON, June; from Parornix sp. on Amelanchier : 7 females, 2 males, CALIFORNIA, OREGON, September; from Perittia sp. on Symphoricarpos albus : 1 female, OREGON, June; from Phyllonorycter antiochella Opler on Quercus agrifolia : 5 females, 1 male, CALIFORNIA, March; from Phyllonorycter crataegella (Clemens) on Crataegus sp. : 3 females, CALIFORNIA, September, December; from Phyllonorycter emberizaepenella (Bouche) on Lonicera bella : 1 male, ONTARIO, October;

from Phyllonorycter salicifoliella (Clemens) on Salix spp. : 26 females, 28 males, ONTARIO, NEW BRUNSWICK, July–October; from Phyllonorycter tremuloidella (Braun) on Populus tremuloides : 29 females, 31 males, ONTARIO, BRITISH COLUMBIA, CALIFORNIA, UTAH, July–September; from Phyllonorycter sp. on Alnus spp. : 2 females, 2 males, CALIFORNIA, NOVA SCOTIA, August, September ;

from Phyllonorycter sp. on Lonicera : 1 female, NEW YORK, (no date); from Phyllonorycter sp. on Quercus lobata : 6 females, 5 males, CALIFORNIA, October;

from Phyllonorycter sp. on Ribes : 2 females, 4 males, CALIFORNIA, September ;

from Phyllonorycter spp. on Salix spp. : 2 females, 1 male, CALIFORNIA, OREGON, June; from Phyllonorycter sp. on Symphoricarpos sp. : 5 females, 1 male, CALIFORNIA, OREGON, June–September; from undetermined leafminers on apple leaves: 4 females, 1 male, OREGON, NOVA SCOTIA, September/October, March .

Not reared: 47 females, 15 males, throughout northern North America (but also Texas (!)), mostly late summer­fall .

Hosts. The above list of hosts under material examined needs no repeating; it may be mentioned that the few individuals on Phyllonorycter spp. on Malus and Lonicera in the eastern U. S. and Quercus in the western states are usually far outnumbered by individuals of P. ornigis and P. salalicus , respectively, on these hosts. In California, in the absence of P. ornigis , P. salicifoliellae occurs commonly on leafminers on Rosaceae , Caprifoliaceae and Saxifragaceae , which are usually parasitized in the east by P. ornigis .

Comments. As with P. ornigis and P. salalicus , there are relatives in Europe which make species separation difficult when the entire world fauna is considered. Particularly confusing is P. ambiguus (Papp) ; I can find no character in Papp's (1977, 1983b) descriptions which will reliably separate P. ambiguus from P. salicifoliellae . Pholetesor laetus (Marshall) is also similar, but appears usually much larger and more brightly colored and apparently does not have a concave hind margin to the second tergite (which may be true for P. ambiguus as well). The entire problem of Holarctic distributions of Microgastrinae needs more attention; I suspect 10–20% of the species, especially northern ones, occur on both continents.

Again, I am not positive that all of the material I have placed under the name P. salicifoliellae is in fact conspecific; the host range is broad, but not inconsistent with what I have seen in P. ornigis and P. salalicus . It is also possible that the name P. salicifoliellae should be synonymized under P. glacialis (Ashmead) (see under that name); the identity of Ashmead's single male is uncertain enough that I hesitate to sink Mason's name under it.

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).