Pholetesor bucculatricis (Muesebeck)

Whitfield, James B., 2006, Revision of the Nearctic species of the genus Pholetesor Mason (Hymenoptera: Braconidae), Zootaxa 1144 (1), pp. 1-94 : 17-20

Pholetesor bucculatricis (Muesebeck)

( figs. 10 , 17 , 33, 35 , 40 , 60 )

Apanteles bucculatricis Muesebeck, 1921 . Proc. U.S. Nat. Mus. 58: 502. Holotype female, USNM no. 22512, examined.

Females. Body length 1.7–2.1 mm; forewing length 1.8–2.1 mm.

Head. Frons 1.3–1.4x broader at midheight than long down middle, shallowly but evenly punctate, with satiny sheen between punctures; inner margins of eyes weakly converging towards clypeus. Antennae entirely dark brown except paler distal portions of pedicels; length approximately 1.1x forewing length; all but apical 5 flagellomeres with 2 ranks of placodes; flagellomere 2 2.9–3.0x longer than broad, flagellomere 14 1.5–1.7x longer than broad. Palpi distally light yellow­brown, proximally darker brown. Head in dorsal view 1.8–1.9x broader than long down midline.

Mesosoma . Mesoscutum with closely spaced, distinct punctation anteriorly, becoming more widely spaced posteriorly near scutellum; surface between punctures shiny, especially posteriorly; mesoscutal width just anterior to tegulae more or less equal to head width. Scutoscutellar scrobe striaght medially, moderately broad and composed of 10–12 deep, fine pits. Scutellar disc with distinct, widely spaced punctures (interstices about 1–2 pit diameters), shinier than mesoscutum, 1.2x as long as anteriorly broad or longer. Metanotum weakly excavated sublaterally along anterior edge just mesad sublateral setiferous projections; projections appressed to posterior edge of scutellum or nearly so; transverse carinae at midlength on either side well­developed, setting off more posterior transverse depressions crossed by 2–3 short carinae. Propodeum 1.7x as broad as long at longest point, with unusually long, nearly horizontal anterior face; anteriorly with strong, short medial longitudinal carina, posteriorly with broad, well­marked pentagonal areola and transverse carinae; otherwise usually weakly punctulorugose and shiny; posterolateral declivous regions deeply sunken, often more strongly and irregularly sculptured than anterior areas.

Legs. All legs dark testaceous to black, especially proximally, except lighter brown apices of fore and mid femora, near entirety of fore tibiae and tarsi, proximal.6–.7 of mid tibiae, rpoximal.9 of mid tarsi and proximal.2–.3 of hind tibiae. Spines on outer faces of hind tibiae usually 25–30 in number. Apical spurs of hind tibiae subequal in length, whitish, about.35–.4 length of hind basitarsus.

Wings. Tegulae dark brown, barely translucent. Forewing venation dark brown, especially stigma, R1, C+Sc=R, 2r, 1Rs, 2M stub and 2Cu1 (with immediate surrounding venation); proximal venation paler; macrotrichiae of wings pigmented (giving some smoky appearance to the wings). 2r and 1Rs subequal in length, meeting at indistinct 140– degree angle. R1 (metacarp) slightly longer than stigma, usually 3x longer than distance from its distal end to end of 3Rsfold along wing edge. Maximum width of stigma just less than half its length. Hindwing with vannal lobe very slightly flattened at midlength, fringe even, long over distal.6–.7 of lobe.

Metasoma. Tergite I broadening posteriorly to weakly rounded apex, slightly broader posteriorly than long, with deep but short mediobasal excavation (at most.25–.3 of tergite length); surface mostly very strongly rugose to logitudinally aciculorugose, strongly arched medially at midlength, sometimes with suggestion of medial depression subapically. Tergite II strongly quadrate, sculptured as on tergite I, 2.3–2.5x as broad as medially long; posterior crenulate margin weakly concave. Tergite III medially subequal in length with II, posterolaterally rounded, coarsely rugose anteriorly, bcoming more logitudinally aciculate posteriorly and laterally. Succeeding terga of usual unsculptured, overlapping form, often strongly shrunken in under anterior 3 in dried specimens. Laterotergites dark brown, barely visible in dorsal view. Hypopygium approximately 1.5x hind basitarsus length, sclerotized and pigmented evenly to sharp medial fold; apical angle in lateral view about 45–50 degrees, not acuminate. Ovipositor sheaths about.6 length of hind tibiae; expanded portions elongate­fusiform, hairy over distal.6 or so, proximally smooth and evenly tapering. Ovipositor very weakly decurved.

Males. Body size similar to females, often appearing smaller due to greater shrinkage of male metasoma. Antennae longer than in female, as much as 1.5x length of forewing, with more elongate apical flagellomeres (flagellomere 14 2.1–2.2x as long as broad); all but apical 3 flagellomeres with 2 ranks of placodes. Leg coloration usually darker than in females but often nearly indistinguishable.

Variation. As yet, this species is known only from California (questionably also from Durango, Mexico), and shows little if any significant geographic variation. The available Sierran individuals are mostly in the small end of the size range, but this is likely due to the different host(s) attacked. If the specimen from Durango is conspecific, there is an indication that further south the coloration of the legs and wing venation becomes much lighter and the propodeal background sculpturing much stronger .

Final instar larva. Labium with one pair of large setae on short tubercles. Maxillae each with 1 seta. Mandibles set with 8–10 long teeth (not counting bifid tip).

Cocoons. All known reared individuals emerged from cocoons of Bucculatrix spp. , within which they spin a thin cocoon of their own after emerging from the host larva (see figure 10 ). Thus unless one dissects the Bucculatrix cocoon, it does not appear that they spin a cocoon of their own at all.

Material examined. Reared from Bucculatrix albertiella Busck on Quercus agrifolia Nee : 51 females, 71 males, all coastal California , adults late March­mid June and early August­mid October. Reared from Bucculatrix sp. on Quercus kelloggii Newb. : 7 females, 3 males, El Dorado Co., Calif., adults September. Reared from Bucculatrix sp. on Ceanothus integerrimus H. & A.: 2 females, Plumas Co. , Calif., adults September. Not reared: 5 females, 12 males, all California , mostly June , July ; one questionable male from Durango, Mexico (July). Specimens in USNM, CNC, CAS, UCB collections .

Hosts. Probably a number of western Bucculatrix species , especially on oaks, can serve as hosts; the Bucculatrix species on Compositae appear to support mainly Pholetesor variabilis , P. masoni and (occasionally) P. bedelliae . By far the most records are from B. albertiella on coastal live oak, from which the parasite can be reared in good numbers in both the spring and fall. It is curious that this moth also serves as host (often at the same time and locality) for P. variabilis and Deuterixys quercicola Whitfield as well, occasionally in more or less equal numbers. Museum records from Bucculatrix thurberiella , a possible host, appear to be misidentifications of P. bedelliae or P. variabilis .

Comments. Pholetesor bucculatricis is most distinct in combining a broad, strongly defined areola and lateral carinae, broad and coarsely sculptured anterior three metasomal tergites, an evenly sclerotized (but medially folded) hypopygium and a slender, nearly straight ovipositor. No specimen on which the propodeum is visible should be easily confused with any other Pholetesor species. In propodeal structure it resembles some Austrocotesia species , but is vastly different in structure of the metasomal tergites and hypopygium. If Pholetesor is ultimately found not to be monophyletic, this species will almost certainly require a new generic name.

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 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).