Braconidae

Kula, Robert R., 2013, A new species and new distribution records for Braconidae from Mountain Lake Biological Station in southwestern Virginia and a redescription of Pentapleura foveolata Viereck, Zootaxa 3641 (5), pp. 501-523 : 504-505

Braconidae of Mountain Lake Biological Station

Seventy-four species of Braconidae are known from MLBS (Table 1). This includes 13 species from Milne and Milne (1944); only one of those species, Austrozele uniformis (Provancher) , was collected through this research. The 14 species listed in Milne and Milne (1944) currently constitute 13 due to subsequent nomenclatural changes. The eight species in Milne and Milne (1944) identified to genus and listed as morphospecies only were not included in Table 1 because they were not available for comparison with specimens from this research. Seven hundred and forty-five specimens of Braconidae were collected through sampling carried out in this research and represented 62 of the 74 braconid species known from MLBS. Not included in Table 1 were 49 specimens determined as Alysiini (n=3), Chorebus Haliday (n=1), Ephedrus Haliday (n=1), Blacus Nees (n=1), and Microgastrinae (n=43) but not sorted into morphospecies because they are either males or damaged. Of the 62 species, Alysiinae and Opiinae were the two richest subfamilies, with 22 and nine species, respectively. Thus, at least 31 of the 62 species are parasitoids of cyclorrhaphous flies (Wharton 1997a, b). Doryctinae , Aphidiinae , and Microgastrinae were the next highest subfamilies in terms of richness, with six, five, and four species, respectively. Aphidiines are exclusively parasitoids of aphids (van Achterberg 1997a), doryctines are primarily parasitoids of wood-boring beetle larvae (Marsh 1997), and microgastrines are exclusively parasitoids of lepidopteran larvae (Whitfield 1997). The remaining 16 species represent nine subfamilies with no more than three species per subfamily. Six of those species are from the subfamilies Cheloninae (3), Macrocentrinae (2), and Orgilinae (1) and thus are parasitoids of lepidopterans (van Achterberg 1997b; Shaw 1997; Wharton 1997c). Considering those species along with the microgastrines, at least 10 of the 62 species are parasitoids of lepidopterans.

An undetermined species of Dinotrema Förster was the most abundant (n=301) (Table 1) followed by an undetermined species of Orthostigma Ratzeburg (n=113). Those two species alone accounted for 56% of the specimens collected through this research. Cratospila neocirce Wharton (n=45) and an undetermined species of Aspilota Förster (n=44) were also abundant relative to the other species collected. Species of Aspilota , Dinotrema , and Orthostigma are primarily parasitoids of flies in the family Phoridae , and their hosts are often associated with fungi (Wharton 1997a; Yu et al. 2005). Given the high diversity of fungi at MLBS and its environs (Linder 1937; Meyer 1943; Graff 1947; Miller 1965), and at the sites sampled (especially Hunter’s Branch, R. Kula pers. obs.), it is likely that species of Aspilota , Dinotrema , and Orthostigma collected through this research attack phorids associated with fungi. Host use is unknown for species of Cratospila Förster (Wharton 1997a; Yu et al. 2005). No more than 17 specimens were collected for any of the remaining species.

Specimens of Spathius Nees from MLBS could not be identified reliably to species despite a recently published review that included a key to species in North America (Marsh & Strazanac 2009). Species are separated in couplet 3 of the key based on malar space length “at least 3/4 eye height” compared to “at most 1/2 eye height.” The malar space:eye height ratios for the two MLBS specimens considered a species near Spathius calligaster Matthews are 0.55 and 0.48. They were taken through both options of couplet 3 and best fit the couplets following malar space length “at most 1/2 eye height.” Both specimens passed easily to couplet 8, where Spathius longipetiolatus Ashmead was differentiated from other species of Spathius based on a “smooth and polished” scutellar disc. However, the scutellar disc transitions, anteriorly to posteriorly, from smooth to coriaceous in S. longipetiolatus based on examination of the lectotype and paralectotype. Therefore, other features must be used to differentiate S. longipetiolatus from congeners. The lectotype of S. longipetiolatus is missing the head and metasoma, and the wings and legs are damaged. The paralectotype is missing the wings and metasoma, and the rest of the specimen is damaged and covered with debris. This makes equivocal identification of S. longipetiolatus extremely difficult. The vertex of the paralectotype is almost entirely obscured but clearly strigate compared to entirely smooth in the MLBS S. sp. nr. calligaster specimens. Therefore, I do not consider them conspecific with S. longipetiolatus . If both specimens are keyed to couplet 9, they fit S. calligaster in that forewing 1CU and 2CU are interstitial; they differ in that t4 is smooth (“acinose” in S. calligaster per Marsh & Strazanac 2009), and the lateral margin of t2+t3 is sharp at the base only (“sharp and distinct” along entire length in S. calligaster per Marsh & Strazanac 2009). If both specimens are keyed to couplet 10, they differ from Spathius evansi Matthews in that the vertex is smooth (strigate in S. evansi ) and metatarsomere 3 is subequal to metatarsomere 5 (3 longer than 5 in S. evansi ). They fit Spathius elegans Matthews in that the vertex and t4 are smooth and metatarsomere 3 is subequal to metatarsomere 5; they differ in that 1CU and 2CU are interstitial (i.e., 2CU is intercepted by 2cu-a in S. elegans ). Thus, the two MLBS specimens of Spathius considered a species near S. calligaster do not precisely fit S. calligaster , S. elegans , or S. evansi sensu Marsh and Strazanac (2009) , but they fit closest to S. calligaster based on examination of primary and/or secondary types for the three species. Examination of S. calligaster paratypes revealed that 1CU and 2CU are not interstitial (i.e., 2CU is intercepted by 2cu-a) and t4 is smooth in some specimens. Thus, S. calligaster sensu Marsh and Strazanac (2009) differs from S. calligaster sensu Matthews (1970) , although the former authors did not state this explicitly. The specimens of Spathius sp. nr. calligaster from MLBS key easily to the couplet containing S. calligaster in Matthews (1970). However, they do not have the head and mesosoma dorsoventrally compressed, and they lack a dorsal transverse swelling on the pronotum, features Matthews (1970) used to define S. calligaster .

Two other species of Spathius were collected at MLBS. Both key easily to couplet 16 in Marsh and Strazanac (2009). Spathius impus Matthews was differentiated at couplet 16 from other species of Spathius based on “ocellaroccipital distance equal to or less than ocellar-ocular distance” and “outer apical margin of hind tibia with 2–3 small spines.” The distance is longer in both species, but both have two spines on the outer apical margin of the hind tibia. Both species differ from Spathius pallidus Ashmead (couplet 17) in terms of mesopleural sculpture and body color, and both species differ from Spathius leiopleuron Marsh and Strazanac (couplet 18) in terms of mesopleural sculpture. Spathius sp. 1 fits Spathius laflammei Provancher (couplet 18) except it has two spines on the outer apical margin of the hind tibia (3–8 in S. laflammei ). Spathius sp. 2 differs from S. laflammei in that the former has the vertex smooth (strigate in S. laflammei ) and two spines on the outer apical margin of the hind tibia (3–8 in S. laflammei ).

Two specimens from MLBS were determined as a species near Ontsira imperator (Haliday) . They differ from specimens in the USNM determined as O. imperator in that the MLBS specimens have the metafemur brownish yellow and the metatibia and metatarsus brown, while those features are entirely yellow in the USNM specimens. Also, the scutellar disc is rugose posteriorly in the MLBS specimens, while it is smooth with punctures in the USNM specimens.

One specimen from MLBS was determined as a species near Diospilus fomitis Mason. It is similar to D. fomitis in that the ovipositor is downcurved apically. Conversely, the MLBS specimen has a sharply defined, pentagonal areola that bears a few rugosities, while the areola in four paratypes of D. fomitis in the USNM is either imperceptible (i.e., propodeum entirely areolate-rugose) or a weakly defined pentagon bearing areolate-rugose sculpture. Also, the head, mesosoma, and metasoma are darker brown in the MLBS specimen than in the paratypes of D. fomitis examined, and the metatibia and metatarsus are yellowish brown in the former compared to yellow in the latter. However, the lighter coloration observed in the paratypes could be an artifact of specimen preservation.

Fifteen species were reported from Virginia for the first time, but nine of those species are known from at least one state that borders Virginia. Noteworthy new distribution records are as follows (known distribution beyond Virginia in parentheses): Aphaereta ithacensis Fischer ( CANADA: Ontario; U.S.A.: Michigan, New York, Ohio [Fischer 1966]), Pentapleura foveolata Viereck ( U.S.A.: Connecticut [Viereck 1917]), Tanycarpa gracilicornis (Nees) (Oriental and Palearctic regions [Yu et al. 2005]; CANADA: Alberta, Ontario; U.S.A.: Alaska [Wharton 1980]), Ascogaster provancheri Dalla Torre ( U.S.A.: Alaska, New Hampshire, New Jersey, New York, Ohio [Yu et al. 2005]), Euphoriella pallidifacia Loan and New ( CANADA: Quebec [Loan & New 1972]), and D. fomitis ( CANADA: Manitoba, Quebec, Saskatchewan [Mason 1968]). The specimens collected at MLBS are the southernmost records for those species.