Antistrophus minor Gillette, 1891

Nastasi, Louis F., Tooker, John F., Davis, Charles K., Smith, Cecil N., Frey, Timothy S., Hatfield, M. J., Presnall, Tara M., Hines, Heather M. & Deans, Andrew R., 2024, Cryptic or underworked? Taxonomic revision of the Antistrophus rufus species complex (Cynipoidea, Aulacideini), Journal of Hymenoptera Research 97, pp. 399-439 : 399-439

Antistrophus minor Gillette, 1891

Fig. 7

Antistrophus minor Gillette, 1891: 195. ♀, ♂ (type locality: unknown location in Illinois, USA).

Aulax gillettei ( Gillette, 1891) : Kieffer 1902: 93.

Material examined.

Lectotype (deposited at INHS; designated by Frison [1927]). USA • ♀; Illinois; reared from stem of Silphium laciniatum ; record number 5500; INHS Insect Collection 212949.

Lectoallotype (deposited at INHS; designated by Frison [1927]). USA • ♂; same data as lectotype; INHS Insect Collection 212950 .

Other material

(24 ♀ and 24 ♂). Deposited at PSUC: USA • 3 ♀; Illinois, Champaign County, Gifford, Shortline Railroad Prairie ; 40.305, - 87.999; JF Tooker and AR Deans leg.; galled plant material collected 10–11 Nov 2020; reared from stem of Silphium laciniatum , emerging in May or June 2021; PSUC _ FEM _ 248257; 253063; 253067 • 2 ♀; Illinois, Iroquois County, Loda, Loda Cemetery Prairie ; 40.528, - 88.074; JF Tooker and AR Deans leg.; galled plant material collected 10 Nov 2020; reared from stem of Silphium laciniatum , emerging in June 2021; PSUC _ FEM _ 248273; 253060 • 2 ♀ and 1 ♂; Illinois, McLean County, Chenoa, Weston Cemetery Prairie ; 40.725, - 88.606; JF Tooker and AR Deans leg.; galled plant material collected 11 Nov 2020; reared from stem of Silphium laciniatum , emerging in May or June 2021; PSUC _ FEM _ 248278; 248283; 248288; 248303 • 3 ♀ and 3 ♂; Illinois, McLean County, Chenoa, Weston Cemetery Prairie ; 40.725, - 88.606; LF Nastasi and AR Casadei leg.; galled plant material collected 16 Oct 2021; reared from stem of Silphium laciniatum , emerging in June 2022; PSUC _ FEM _ 253166–253168; 253170; 253180; 253192 • 1 ♀ and 2 ♂; Iowa, Story County, Grant, Interstate 35 and E 13 th St prairie restoration; MJ Hatfield leg.; galled plant material collected 30 Nov 2020; reared from stem of Silphium laciniatum , emerging in May or June 2021; PSUC _ FEM _ 248265; 248291; 248295 • 1 ♂; Iowa, Winneshiek County, Decorah Community Prairie ; MJ Hatfield leg.; galled plant material collected 18 Apr 2022; reared from stem of Silphium laciniatum , emerging in May or June 2022; PSUC _ FEM _ 253229 • 3 ♀ and 2 ♂; Iowa, Winneshiek County, Plymouth Rock Prairie ; 43.438, - 92.006; MJ Hatfield leg.; galled plant material collected 17 Apr 2016; reared from stem of Silphium laciniatum , emerging in May 2016; PSUC _ FEM _ 253085; 253088; 253089; 253090; 253094 .

Deposited at USNM: USA • 1 ♀; Illinois, McLean County, Chenoa, Weston Cemetery Prairie ; 40.725, - 88.606; JF Tooker and AR Deans leg.; galled plant material collected 11 Nov 2020; reared from stem of Silphium laciniatum , emerging in May or June 2021; PSUC _ FEM _ 248286 • 1 ♀; Illinois, McLean County, Chenoa, Weston Cemetery Prairie ; 40.725, - 88.606; JF Tooker and AR Deans leg.; galled plant material collected 11 Nov 2020; reared from stem of Silphium laciniatum , emerging in May or June 2021; PSUC _ FEM _ 248303 • 3 ♂; Illinois, McLean County, Chenoa, Weston Cemetery Prairie ; 40.725, - 88.606; LF Nastasi and AR Casadei leg.; galled plant material collected 16 Oct 2021; reared from stem of Silphium laciniatum , emerging in June 2022; PSUC _ FEM _ 253190; 253191; 253194 • 1 ♀; Illinois, McLean County, Chenoa, Weston Cemetery Prairie ; 40.725, - 88.606; LF Nastasi and AR Casadei leg.; galled plant material collected 16 Oct 2021; reared from stem of Silphium laciniatum , emerging in June 2022; PSUC _ FEM _ 253165 .

Deposited at WIRC: USA • 1 ♀; Iowa, Blackhawk County, Hudson Railroad Prairie ; 42.436349, - 92.427034; DNR Study SSGB leg.; galled plant material collected 2 May 2009; reared from stem of Silphium laciniatum , emerging in June 2009; WIRC 00170819 • 1 ♀; Iowa, Linn County, Walford 2; 41.883014, - 91.825962; DNR Study SSGB leg.; galled plant material collected 3 May 2009; reared from stem of Silphium laciniatum , emerging in June 2009; WIRC 00170772 • 1 ♂; Wisconsin, Columbia County, Goose Pd. Sue Ames ; DNR Study SSGB leg.; galled plant material collected Fall 2008; reared from stem of Silphium laciniatum , emerging in July 2009; WIRC 00170816 • 1 ♀; Wisconsin, Columbia County, Hopkins Restoration ; DNR Study SSGB leg.; galled plant material collected Fall 2008; reared from stem of Silphium laciniatum , emerging in July 2009; WIRC 00170661 • 1 ♂; Wisconsin, Dane County, Badger Pr. Park North ; DNR Study SSGB leg.; galled plant material collected 3 Apr 2012; reared from stem of Silphium laciniatum , emerging in May 2012; WIRC 00170757 • 1 ♂; Wisconsin, Dane County, E-way @ Mooreland; DNR Study SSGB leg.; galled plant material collected 4 Apr 2012; reared from stem of Silphium laciniatum , emerging in Apr 2012; WIRC 00170683 • 2 ♀; Wisconsin, Dane County, Smith Drumlin ; 42.98988, - 89.06097; DNR Study SSGB leg.; galled plant material collected 15 Apr 2009; reared from stem of Silphium laciniatum , emerging in May 2009; WIRC 00170786 ; 00170788 • 2 ♂; Wisconsin, Dane County, Waubesa Wetlands ; WDNR Misc / SB Sauer leg.; galled plant material collected Apr 2007; reared from stem of Silphium laciniatum , emerging before 19 May 2007; WIRC 00170805 ; 00170807 • 2 ♂; Wisconsin, Grant County, Dewey Heights Prairie ; 42.734647, - 91.020306; DNR Study SSGB leg.; galled plant material collected 14 Oct 2011; reared from stem of Silphium laciniatum , emerging in May 2012; WIRC 00170664 ; 00171400 • 2 ♀; Wisconsin, Green County, Green Cemetery Prairie ; DNR Study SSGB leg.; galled plant material collected 4 Apr 2012; reared from stem of Silphium laciniatum , emerging in May 2012; WIRC 00170663 ; 00170758 • 1 ♂; Wisconsin, Green County, Muralt - South ; 42.695505, - 89.49367; DNR Study SSGB leg.; galled plant material collected 4 Apr 2012; reared from stem of Silphium laciniatum , emerging in May 2012; WIRC 00170754 • 1 ♂; Wisconsin, Iowa County, Hollandale Seed Orchard ; DNR Study SSGB leg.; galled plant material collected 5 Apr 2012; reared from stem of Silphium laciniatum , emerging in May 2012; WIRC 00170756 • 1 ♂; Wisconsin, Iowa County, TNC / Lease ; 42.97357, - 89.88900; DNR Study SSGB leg.; galled plant material collected 17 Apr 2009; reared from stem of Silphium laciniatum , emerging in May 2009; WIRC 00170678 • 1 ♂; Wisconsin, Kenosha County, Bain Station ; 42.556352, - 87.893763; DNR Study SSGB leg.; galled plant material collected 30 Sep 2011; reared from stem of Silphium laciniatum , emerging in May 2012; WIRC 00170778 • 1 ♀; Wisconsin, Waukesha County, Scuppernong Prairie State Natural Area ; 42.89947, - 88.50180; DNR Study SSGB leg.; galled plant material collected 15 Apr 2009; reared from stem of Silphium laciniatum , emerging in June 2009; WIRC 00170637 .

Diagnosis.

A. minor is the only described species of Antistrophus in which the mesoscutellar disc is strongly ovate and distinctly wider than long (Fig. 7 F ). Additionally, A. minor is easily separable from A. rufus (which also induces inconspicuous galls in stems of the S. laciniatum ) and A. meganae by the shape and length of the mesoscutellar foveae; in A. minor , the mesoscutellar foveae are subquadrate and reach about one third across the mesoscutellar disc (Fig. 7 F ) but are shorter and subrectangular in A. rufus (Fig. 8 F ) and longer and ovate in A. meganae (Fig. 6 F ). A. minor and A. meganae are also the only species of the rufus complex in which the POL is longer than the OOL. See additional comments in the diagnosis to A. rufus .

Description.

Female (Fig. 7 A ) – Body length: 1.4–2.4 mm (x ̄ = 2.0 mm; n = 25; lectotype = 2.3). Color: Antenna color: red brown throughout, at most slightly darker distally than proximally. Head color: vertex and occiput dark red brown, mandibles red brown basally to darker red brown apically, rest of head red brown throughout. Color: pronotum and propodeum mostly red brown, with some dark red brown coloration medially, mesoscutum dark red brown with at least distinct red brown spots posterolaterally, scutellum red brown to dark red brown, and mesopleuron dark red brown to red brown. Wing membrane color: hyaline throughout. Wing vein color: light brown. Leg color: red brown throughout, except for apical tarsomere which is conspicuously darker. Metasoma color: red brown to dark red brown. Antennae (Fig. 7 B ): Antennomere count: 13. F 1 length: 2.6 × as long as wide. F 2 length: 3.6 × as long as wide. F 2: F 1 length ratio: 1.4. Placodeal sensilla on F 2: absent; sensilla present only on F 3 and following antennomeres. Head (Fig. 7 C ): Upper frons sculpture: reticulate. Gena posterolateral projection in anterior view: distinctly projecting past compound eyes. Facial radiating striae: distinct and complete, reaching compound eyes. Supraclypeal area sculpture: reticulate. Supraclypeal area projection: slightly projecting. OOL vs POL: POL distinctly longer. OOL vs LOL: OOL twice LOL. POL vs LOL: POL greater than twice LOL. LOL vs DLO: LOL longer. Vertex sculpture: reticulate throughout. Clypeus sculpture: reticulate. Mesosoma (Figs 7 D – F ): Pronotum pilosity: densely pilose along anterior margin and with only sparse setae elsewhere. Pronotum excluding pronotal plate sculpture: reticulate. Pronotal plate sculpture: reticulate. Mesopleuron excluding speculum sculpture: reticulate with fine intermediate striae. Speculum sculpture: reticulate. Mesopleuron pilosity: ventral margin and mesopleural triangle densely pilose and bare elsewhere. Mesoscutum pilosity: sparsely pilose. Mesoscutum sculpture: reticulate. Apparent length of anterior parallel lines: reaching one third across mesoscutum. Morphology of anterior parallel lines: narrow, distinct throughout perceptible length. Apparent length of parapsidal grooves: reaching halfway across mesoscutum. Morphology of parapsidal grooves: narrow, distinct throughout perceptible length. Morphology of median mesoscutal impression: apparent as a shallow impression extending across most of mesoscutum. Notauli completeness: incomplete, distinct posteriorly to indistinct in anterior third. Morphology of notauli: appearing as wide indentations with sloping edges throughout distinct portions. Metapleural sulcus: meeting posterior mesopleuron at about one third of its height. Lateral propodeal carinae: distinct and subparallel. Metapleuron sculpture: reticulate. Mesoscutellar foveae distinction: distinct, relatively deep anteriorly to shallower and inconspicuously delimited posteriorly. Mesoscutellar foveae sculpture: reticulate. Mesoscutellar disc sculpture: rugose-reticulate, primarily reticulate, but with distinct rugose-reticulate sculpture seemingly restricted to outer margins. Mesoscutellar foveae length: long, reaching about one third across mesoscutellar disc. Mesoscutellar foveae shape: subovate, slightly longer than wide, separated by a narrow linear carina. Mesoscutellar disc shape: ovate, distinctly longer than wide. Wings: Marginal cell length: 3.1 × as long as wide. Fore wing distal fringe of marginal setae: absent. Metasoma: Punctation of metasomal terga: T 3 punctate only in posterior third and with T 4 and following punctate throughout.

Male (Fig. 7 G ) – Same as female except for the following: Body length: 1.1–2.0 mm (x ̄ = 1.6; n = 25). Antennae: Antennomere count: 14. F 1 length: 2.3 × as long as wide. F 2 length: 2.9 × as long as wide. F 2: F 1 length ratio: 1.3. Placodeal sensilla on F 2: present. Wings: Fore wing distal fringe of marginal setae: present. Metasoma: Metasoma size: conspicuously smaller than in female.

Biology.

Antistrophus minor induces inconspicuous, externally imperceptible galls in stems of Silphium laciniatum (Fig. 7 H ) ( Tooker et al. 2004; Nastasi and Deans 2021). Weld (1926) reported A. minor from Silphium terebinthinaceum , but Weld’s specimens from this host plant truly represent Antistrophus meganae .

Distribution.

Antistrophus minor was described from adults reared alongside A. rufus in Illinois. We examined specimens providing new state records from Iowa and Wisconsin. Known and potential distribution are summarized in Fig. 9 . It appears that A. minor is likely sympatric with A. rufus throughout the distribution of S. laciniatum , although further rearing of Silphium species will be needed to better understand the role of geography in the distribution of Antistrophus , especially regarding these two species.

Remarks.

See remarks under Antistrophus rufus for notes on generic nomenclature and distinction of A. minor from A. rufus .

Figures

Figure 6. Antistrophus meganae Tooker & Hanks, 2004 A female lateral habitus (PSUC _ FEM _ 248165) B female proximal antennomeres (PSUC _ FEM _ 247325) C female dorsal head (PSUC _ FEM _ 247325) D female dorsal mesosoma (PSUC _ FEM _ 247230) E female dorsal mesoscutum (PSUC _ FEM _ 247230); not = notaulus F female dorsal scutellum (PSUC _ FEM _ 247230); scf = mesoscutellar fovea G male lateral habitus (PSUC _ FEM _ 248498) H gallss and larvae of A. meganae in a stem of Silphium terebinthinaceum Jacq.

Figure 7. Antistrophus minor Gillette, 1891 A female lateral habitus (PSUC _ FEM _ 248273) B female proximal antennomeres (PSUC _ FEM _ 253176) C female dorsal head (PSUC _ FEM _ 253091) D female dorsal mesosoma (PSUC _ FEM _ 248257) E female dorsal mesoscutum (PSUC _ FEM _ 248257); not = notaulus F female dorsal scutellum (PSUC _ FEM _ 248257); scf = mesoscutellar fovea G male lateral habitus (PSUC _ FEM _ 253191) H gallss and larvae of A. minor or A. rufus in a stem of Silphium laciniatum L.

Figure 8. Antistrophus rufus Gillette, 1891 A female lateral habitus (PSUC _ FEM _ 248316) B female proximal antennomeres (PSUC _ FEM _ 246062) C female dorsal head (PSUC _ FEM _ 246062) D female dorsal mesosoma (PSUC _ FEM _ 253129) E female dorsal mesoscutum (PSUC _ FEM _ 253129); not = notaulus F female dorsal scutellum (PSUC _ FEM _ 253129); scf = mesoscutellar fovea G male lateral habitus (PSUC _ FEM _ 248308) H gallss and larvae of A. minor or A. rufus in a stem of Silphium laciniatum L.

Figure 9. Known and potential distributions for species of the Antistrophus rufus complex. Host plant distribution follows Kartesz (2015). States in green reflect established distribution, while states in yellow reflect potential distribution based on records of the host plant.