Pholetesor salalicus (Mason)

Whitfield, James B., 2006, Revision of the Nearctic species of the genus Pholetesor Mason (Hymenoptera: Braconidae), Zootaxa 1144 (1), pp. 1-94 : 68-72

Pholetesor salalicus (Mason)

( figs. 11, 12, 15 , 29 , 56 , 76 , 85 )

Apanteles salalicus Mason, 1959 . Canad. Entomol. 91: 42. Holotype female, USNM no. 64302, examined. Assigned to Pholetesor Mason by Mason, 1981, Mem. Entomol. Soc. Canada 115.

Females. Body length 1.6–2.7mm, forewing length 1.8­2.8mm.

Head. Frons 1.2–1.3x as broad at midheight as long down midline, shallowly punctate; inner margins of eyes weakly converging towards clypeus. Antennae slightly longer than body; scape light yellow­brown proximally, darker distally; all but distal 4–5 flagellomeres with 2 ranks of placodes; flagellomere 2 3.4–3.7x as long as broad; flagellomere 14 1.6–1.9x as long as broad. Palpi pale yellow­brown throughout. Head in dorsal view approximately twice as broad as medially long.

Mesosoma . Mesoscutum in dorsal view about.95x as broad as head, shallowly punctate, becoming less strongly so posteriorly; surface with strong satiny sheen. Pronotal furrow distinctly but irregularly crenulate. Scutoscutellar scrobe sharp, narrow, composed of somewhat confluent pits, arched weakly medially, not set in depression. Scutellar disc shallowly punctate, slightly longer than maximum width. Metanotum strongly retracted from scutellum anteriorly, exposing mesothoracic postphragma; broadly excavated mesad sublateral setiferous projections; transverse carinae at about midlength poorly to moderately developed. Propodeum about 1.7x broader than long at longest point, punctate to weakly rugulose anterolaterally, smooth and depressed in posterolateral corners except for scattered irregular peripheral ridges; anteromedially with weak transverse ridging; posteriorly with a series of ridges extending obliquely on either side from nucha.

Legs. Prothoracic and mesothoracic legs entirely light yellow­brown except infuscate extreme bases of coxae, tibial apices and most of distal portions of tarsi. Spines on outer faces of hind tibiae 30–35 in number, irregularly scattered, all of one kind. Inner apical spurs of hind tibiae 1.2–1.3x as long as outer, about half as long as hind basitarsi to slightly shorter.

Wings. Tegulae pale yellowish, translucent. Forewing venation pigmented light yellow­brown; stigma usually paler proximally or over much of surface. R1 slightly longer than stigma, 2–3x as long as distance from its distal end to end of 3Rs fold along wing edge. 2r curved, usually slightly shorter than 1Rs and meeting it at an indistinct curved angle. Hindwing with vannal lobe weakly flattened subapically, evenly fringed with hairs of moderate length.

Metasoma. Tergite 1 anteriorly longitudinally costulate around basal excavation, posteriorly rugose to aciculorugose, 2.4–2.8x as long as posteriorly broad, narrowing posteriorly, usually with lateral margins nearly straight. Tergite II rugose, subtriangular to trapezoidal, 1.8–2.2x as broad posteriorly as medially long and 1.7–2.0x as broad posteriorly as anteriorly; lateral margins straight to weakly arched, often bordered by roughened, darkened regions of laterotergites; posterior crenulate margin nearly straight. Tergum III longer than II, sculptured anteromedially but only over small area, mostly smooth and similar to succeeding terga; color often mostly yellow­brown in lighter individuals to dark brown. Laterotergites pale yellow­brown, contrasting brightly with tergites except occasionally when tergites are lighter orange­brown. Hypopygium slightly longer than hind basitarsi, evenly pigmented and sclerotized to medial fold; tip weakly acuminate, forming angle of about 60 degrees in lateral view. Ovipositor sheaths weakly decurved over expanded distal portions, tapering evenly broader to beveled/pointed tip (point produced by apical brush); entire length slightly longer than hind basitarsi; appearance similar to sheaths of ornigis and salicifoliellae but tending to be slightly broader, especially in larger individuals. Ovipositor weakly decurved.

Males. Antennae longer than in females, clearly longer than body or forewings, with more slender distal flagellomeres (flagellomere 14 2.2–2.5x as long as broad); all but distal 3 flagellomeres with 2 ranks of placodes. Coloration of legs similar to females but usually more subdued yellowish­brown; extent of dark coloration on hind coxae, tibiae often greater. Tegulae sometimes much darker than in females. Wing venation usually more darkly grey­brown. Metasomal tergites similar to those of female but less roughly sculptured (often with more longitudinal trend to sculpturing); tergite I usually with more curved lateral margins; tergite II often less transverse, about 1.2–1.3x broader posteriorly than medially long. Laterotergites varying from light as in females to considerably deeper yellow­brown.

Variation. This species as delimited is perhaps the most variable in the genus, and may include populations that may eventually prove to be biologically distinct entities. Most of the variation seems to be host­dependent, rather than geographic, in nature.

Specimens from the type­host, Cameraria gaultheriella , tend to be large (body length 2.2–2.7mm) and very contrastingly colored, with long extremely straight­sided first metasomal tergites. Individuals reared from Cameraria sp. on Myrica californica are very similar, but these tend to have shorter first tergites and somewhat smaller overall body size. Also extremely similar are series from Cameraria nemoris on Vaccinium ovatum and Caloptilia ferruginella on Rhododendron occidentale , except that these are generally small (especially from C. nemoris —body size 1.6–1.9mm) with somewhat darker brown wing venation and antennae and having less tendency for the laterotegites to be darkly pigmented and sculptured adjacent to the first tergite.

A large number of examined specimens from various blotchminers, especially lithocolletine gracillariids, on Quercus spp. , at first appeared to represent a distinct species, with somewhat curved lateral margins to the first tergite and more transverse second tergites (posterior width 2.0–2.2x medial length). In addition, sexual dimorphism tends to be stronger than in the other series; males are usually much darker than females, with shorter first tergites and less transverse second tergites. This complex of morphotypes exhibits a great range of color differences—from individuals with largely yellow­brown metasomata (terga III and IV may be largely yellowish, especially laterally), entirely yellow hind coxae, light antennae and wing venation, to others with mostly darkened hind coxae, largely infuscate stigmas, dark antennaem and only the laterotergites of the metasoma light in color. The color range may be largely due to seasonal or microhabitat differences in temperature and humidity (lighter individuals tend to appear in more southerly and/or low elevation localities).

Phenetically intermediate in coloration, tergite shape and, to some extent, size, are individuals reared from Cameraria spp. on Castanopsis spp. and Lithocarpus densiflorus . It is this intermediacy that leads me to consider the entire complex to be one variable species, in which much of the variation is host­dependent. It is also interesting that many of the host Cameraria , especially on Myrica californica , Gaultheria shallon , Vaccinium ovatum , Castanopsis sempervirens , C. chrysophylla , Lithocarpus densiflorus and Quercus agrifolia , were suggested by Opler (1974) and Opler and Davis (1981) to be each other's closest relatives. These plants and moths are all currently sympatric in northern California, providing many opportunities for host­switching on the parts of both moths and wasps.

A number of other hosts are less commonly utilized. These include leafminers on Kalmia , Arctostaphylos , Ribes , Salix , Populus , Artemisia and Lepechinia calycina . The general pattern appears to be a preference for gracillariid leafminers on Ericaceae and Fagaceae , with some switching onto other nearby blotchminers in the same habitats. Two females from Cremastobombycia sp. on Lepechinia calycina (Mt. Diablo, California) are very dark in leg, wing venation, and laterotergite coloration, and have more slender, straight and longer ovipositor sheaths than are typical for P. salalicus . In addition, the cocoons are narrowly banded as in P. salicifoliellae ; cocoons of P. salalicus otherwise seem to be banded only in material from Cameraria spp. on Gaultheria , Myrica and Lithocarpus and then only with a broad central translucent band. These specimens from Cremastobombycia are quite tentatively assigned to P. salalicus .

Final instar larva. Labium with 6–7 pairs of setae; maxillae each with 2 setae; mandibles set with 16–24 long teeth, not counting bifid tip.

Cocoons. White, capsule­like, smooth, elongate­oval, from entirely translucent to opaque whitish at ends leaving broad medial translucent band. Suspended within the mine or shelter of the host by a thread from each end.

Material examined. Reared from Caloptilia azaleella (Brants) on ornamental azaleas: 32 females, 1 male, CALIFORNIA, OREGON, May, September–December ;

from C. ferruginella on Rhododendron occidentale : 2 females, 3 males,

CALIFORNIA, September; from C. nondeterminata (Braun) on Ribes sanguineum : 1 female, CALIFORNIA, August; from C. palustriella (Braun) on Salix sp. : 2 females, CALIFORNIA, July, October; from Caloptilia sp. on Quercus agrifolia : 1 female, 1 male, CALIFORNIA, April; from Cameraria agrifoliella (Braun) on Quercus agrifolia : 54 females, 49 males, CALIFORNIA, February–October but most common April and September; from C. gaultheriella (Walsingham) on Gaultheria shallon : 9 females, 12 males, CALIFORNIA, OREGON, March–August; from C. nemoris (Walsingham) on Vacccinium ovatum : 19 females, 18 males, CALIFORNIA, March–May, July–September; from C. sempervirensella Opler on Castanopsis sempervirens : 32 females, 7 males, CALIFORNIA, March–June, October; from C. walsinghami Opler on Lithocarpus densiflorus : 6 females, 1 male, CALIFORNIA, July; from C. wislizeniella Opler on Quercus agrifolia : 29 females, 19 males, CALIFORNIA, February–April; from C. wislizeniella Opler on Q. wislizenii : 27 females,

22 males, CALIFORNIA, March–May; from Cameraria sp. on Myrica californica : 10 females, 9 males, May, July–August; from Cameraria sp. on Quercus alvordiana : 1 female, 2 males, CALIFORNIA, February, October; from Cameraria sp. on Q. chrysolepis : 2 females, CALIFORNIA, March, April; from Cameraria spp. on Q. douglasii : 2 females, 1 male, CALIFORNIA, June; from Cameraria spp. on Q. dumosa : 9 females, 10 males, CALIFORNIA, February–April; from Cameraria sp. on Q. durata : 2 females, 4 males, CALIFORNIA, March; from Cameraria sp. on Q. garryana : 2 females, 3 males, CALIFORNIA, June; from Cameraria sp. on Q. kelloggii : 2 females, CALIFORNIA, September–October; from Cameraria spp. on Q. lobata : 1 male, CALIFORNIA, September; from Cameraria sp. on Q. sadleriana : 7 females, 3 males, CALIFORNIA, OREGON, June, October; from Cameraria sp on Q. vaccinifolia : 8 females, 3 males, CALIFORNIA, April, June–October; from Cameraria sp. (host not given): 5 females, OREGON, September; from Cnephasia longana (Haw.) on crimson clover: 1 female, OREGON, June; from Cremastobombycia sp. on Lepechinia calycina : 2 females, CALIFORNIA, March; from " Lithocolletis " sp. on Populus : 2 females, CALIFORNIA, September; from " Lithocolletis " spp. (hosts not given): 5 females, 3 males, OREGON, BRITISH COLUMBIA, June, July; from Phyllonorycter sandraella Opler on Quercus agrifolia : 1 female, 1 male, CALIFORNIA, May, October; from Phyllonorycter sp. on Arctostaphylos spp. : 8 females, 11 males, CALIFORNIA, March– April; from Phyllonorycter sp. on Castanopsis : 1 female, 3 males, CALIFORNIA, March; from Phyllonorycter sp. on Kalmia polifolia : 1 female, CALIFORNIA, June; from Phyllonorycter sp. on Lithocarpus densiflorus : 6 females, 4 males, CALIFORNIA, June; from Phyllonorycter sp. on Quercus douglasii : 1 male, CALIFORNIA, October; from Phyllonorycter sp. on Q. dumosa : 10 females, 2 males,

CALIFORNIA, February, April; from Phyllonorycter sp. on Q. durata : 4 females, 8 males, CALIFORNIA, January, March; from Phyllonorycter sp. on Q. garryana : 1 female, 3 males, CALIFORNIA, OREGON, October–December; from Phyllonorycter sp. on Q. kelloggii : 1 female, 2 males, CALIFORNIA, October; from Phyllonorycter sp. on Q. lobata : 5 females, 10 males, CALIFORNIA, June, September–October; from Phyllonorycter sp. on Q. vaccinifolia : 4 females, 2

males, CALIFORNIA, July–September; from Phyllonorycter sp. on Q. wislizenii : 1 female, 1 male, CALIFORNIA, May–June; from Stilbosis dulcedo (Hodges) on Quercus agrifolia : 6 males, CALIFORNIA, April; from Tischeria sp. on Quercus lobata : 2 males, CALIFORNIA, December; from undetermined leafminer on Artemisia suksdorfi : 1 male, CALIFORNIA, August; from undetermined leafminer on Artemisia sp. : 1 male, CALIFORNIA, May; from undetermined leafminer (possibly Eriocraniidae ) on Quercus douglasii : 2 males, CALIFORNIA, June; from undetermined leafminer on Salix sp. : 1 female, OREGON, June. Not reared: 12 females, 5 males, CALIFORNIA, late spring, fall.

Hosts. The above list of material examined provides a full account of the known hosts; I can only add that I doubt the record from Cnephasia longana (Tortricidae) is accurate. Most of the hosts are blotchminers in coastal forest, oak woodland and chaparral vegetation in California and Oregon.

Comments. Many of my general comments have been expressed above under "variation". The species is often difficult to separate from P. salicifoliellae ; the diagnostic characters given in the key are the most useful I have found.

As Nixon (1973) pointed out, P. salalicus bears some resemblance to the Palearctic P. exiguus (Haliday) . The coloration of the wing veins and stigma, legs (except hind coxae), sculpturing of the metasomal tergites (but not their exact shapes— P. exiguus has a broader first tergite with rounded lateral margins and a somewhat longer second tergite) and cocoon are quite similar. Also showing some strong resemblance in the Palearctic fauna is P. laetus (Marshall) , which shares a number of color and tergite features with P. salalicus , but has a less strongly triangular second tergite than P. salalicus and has a completely opaque whitish cocoon, in the material I have seen. The three species are not so similar to suggest conspecificity to the extent of the P. nanus / P. ornigis comparison.

The sex ratio of P. salalicus is partially dependent on the host attacked, apparently due to size differences. Individuals reared from the largest hosts, Cameraria gaultheriella and Caloptilia azaleella , were 88.6 and 97.0% females, respectively (n= 105, 33); from a small host in the same general habitat, Cameraria nemoris , individuals were 51.4% females (n= 37).

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).