Cotesia nuellorum Whitfield

Whitfield, James B., Jr., Robert J. Nuelle & III, Robert J. Nuelle, 2018, A new species of Cotesia Cameron (Hymenoptera, Braconidae, Microgastrinae) reared from the hickory horned devil, Citheroniaregalis, and luna moth, Actiasluna, in east Texas, ZooKeys 740, pp. 35-44 : 38-39

Cotesia nuellorum Whitfield sp. n. Figs 3, 4-7

Type locality.

The original habitat is located within the Sam Houston National Forest, Walker County, Texas, near Stubblefield Lake Recreational area 338 feet AMSL (Lat: 30.524930 Lon: -95.622750 Accuracy: 10 m). This area is described as Pineywoods: Pine Forest or Plantation, according to the Texas Parks and Wildlife; Texas Ecosystem Analytical Mapper (TPWDT.E.A.M.) application. It is in a managed National Forest and is subject to occasional fire events. This successional area contains sweetgum, hickory, oak and various conifers as dominant trees. Many of the deciduous trees are relatively short (less than 6 feet tall) near the borders of roads and trails, and the generally open forest floor is thus highly convenient for sampling caterpillars.

Holotype.

Female deposited in USNM. TEXAS: Walker Co., Sam Houston National Forest, nr. Stubblefield Lake, 30.524930, -95.622750, October 2014, 100 m. elev., coll. R. J. Nuelle, Jr. and R. J. Nuelle, III, ex larva Citheronia regalis on sweetgum.

Paratypes.

4 females, 1 male with same data as holotype, plus 26 females, 7 males (deposited in CNC, INHS, SHSU, TAMUIC, UWIM (Laramie)) from: TEXAS: Walker Co., Sam Houston National Forest, Stubblefield Lake, ex. larva Actias luna on sweetgum, em. 21-22-X-2012, coll. R. S. Peigler.

Description.

Female. Body color: body mostly dark except palps, portions of legs (see below) and ventral portions of anterior laterotergites. Antenna color: scape black, pedicel dark brown, flagellum dark brown/black. Coxae color (pro-, meso, metacoxa): honey yellow; honey-yellow; black proximally, shading to medium brown distally. Femora color (pro-, meso-, metafemur): honey-yellow; honey-yellow; honey-yellow with smoky spot dorsally near distal end. Tibiae color (pro-, meso-, metatibia): honey-yellow; honey-yellow; honey-yellow with darkened extreme distal end. Tegula and humeral complex color: tegula dark brown translucent, humeral complex dark brown translucent (both slightly more translucent and paler in males). Pterostigma color: dark greyish brown, with indistinct paler junction with C+SC. Fore wing veins color: partially pigmented (a few veins may be dark but most are pale - see figure for pattern). Antenna length/body length: antenna approximately as long as body (head to apex of metasoma). Body in lateral view: not distinctly flattened dorso–ventrally. Body length (head to apex of metasoma): 2.0-2.2 mm. Fore wing length: 2.2-2.4 mm. Ocular–ocellar line/posterior ocellus diameter: 2.3-2.5. Interocellar distance/posterior ocellus diameter: 2.0-2.2. Antennal flagellomerus 2 length/width: 2.9-3.1. Antennal flagellomerus 14 length/width: 1.9-2.1. Length of flagellomerus 2/length of flagellomerus 14: 2.1-2.3. Metafemur length/width: 3.2-3.3. Metatibia inner spur length/metabasitarsus length: 0.4-0.5, about 10% longer than outer spur. Anteromesoscutum: mostly with shallow, dense punctures (separated by less than 2.0 × maximum diameter), but with polished and virtually punctureless strip near scutoscutellar sulcus. Mesoscutellar disc: mostly punctured but sometimes indistinctly so. Number of pits in scutoscutellar sulcus: 9 or 10. Propodeal carinae: strong medial longitudinal carina, vague hints of a transverse carina both otherwise rugose, especially medially and anteriorly. Mediotergite 1 length/width at posterior margin: 0.9-1.1. Mediotergite 1 shape: barrel-shaped, broadest in posterior 0.2. Mediotergite 1 sculpture: mostly sculptured, albeit shallowly, otherwise shiny, especially anteriorly. Mediotergite 2 width at posterior margin/length: 2.0-2.2. Mediotergite 2 sculpture: punctate/rugose, but shinier and smoother laterally. Outer margin of hypopygium: evenly sclerotized, posterior margin reaching tip of metasoma and forming a shallow even convex curve. Ovipositor thickness: evenly narrowing towards tip. Ovipositor sheaths exerted but visible portion shorter than hypopygium length. Length of fore wing veins r/2RS: 1.1-1.2. Length of fore wing veins 2RS/2M: 1.1-1.3. Length of fore wing veins 2M/(RS+M)b: 0.9-1.0. Pterostigma length/width: 3.1-3.5. Point of insertion of vein r in pterostigma: at roughly half way point length of pterostigma. Angle of vein r with fore wing anterior margin: nearly perpendicular, slightly inclined towards fore wing apex. Shape of junction of veins r and 2RS in fore wing: distinctly but not strongly angled.

Male. As female but with slightly darker legs, more polished tergites and sometimes more translucent and paler tegulae. Body size usually about 10 % smaller than female.

Molecular data.

None yet recorded. A broad sample of Cotesia reared from various larger Nearctic saturniids would be useful to clarify how distinct the parasitoid species are both in terms of host specificity and in terms of geographic distribution. In Costa Rica, where the diversity of Saturniidae is higher, the host specificity, at least to host genus, appears high ( Smith et al. 2008; Janzen and Hallwachs 2017).

Biology /ecology.

Gregarious (Fig. 3) on early instar larvae of host. Host: Saturniidae : Ceratocampinae: Citheronia regalis (F.) and Saturniinae: Actias luna (L.). 4th and 5th instar larvae do not appear to serve as hosts, as with some other Cotesia parasitizing large Sphingidae and Saturniidae .

Distribution.

Known so far only from Texas but likely to be much more widely distributed.

Ecologically and/or morphologically similar species.

Table 1 provides a comparison of the species so far known from saturniids in North America.

Etymology.

This species is named by JBW for the original discoverers, Robert J. Nuelle, Jr. and Robert J. Nuelle, III.