Idris elba Talamas, 2019

Lomeli-Flores, J. Refugio, Rodriguez-Rodriguez, Susana Eva, Rodriguez-Levya, Esteban, Gonzalez-Hernandez, Hector, Gariepy, Tara D. & Talamas, Elijah J., 2019, Field studies and molecular forensics identify a new association: Idris elba Talamas, sp. nov. parasitizes the eggs of Bagrada hilaris (Burmeister), Journal of Hymenoptera Research 73, pp. 125-141 : 125

Idris elba Talamas sp. nov.

Figures 3-5 , 7 , 9 , 10 , 16 , 21

Description.

Female body length: 0.85-1.16 mm (n=9). Male body length: 0.96-1.07 mm (n=2).

Head. Color of antenna: pale brown to black. Claval formula: 1-2-2-1. Mandible: tridentate, teeth of equal size. Number of clypeal setae: 6. Length of central keel: extending to midpoint of frons. Facial striae: short, not reaching ventral limit of compound eye. Malar striae: short and weakly indicated, not reaching ventral limit of compound eye. Hyperoccipital carina: present. Occipital carina: present ventrally, absent above midpoint of compound eye.

Mesosoma. Pronotal suprahumeral sulcus: absent. Epomial carina: absent. Pronotal cervical sulcus: absent. Dorsal terminus of netrion sulcus: ventral to anterior thoracic spiracle. Netrion sulcus: comprised of foveae, foveae elongate at midpoint of sulcus. Mesoscutal suprahumeral sulcus: foveate. Mesoscutal humeral sulcus: foveate. Scutoscutellar sulcus: smooth medially, foveate laterally in axillar area. Interior of axillar crescent: smooth. Posterior mesoscutellar sulcus: foveate, continuous around posterior and lateral margins of scutellar disc. Metanotal trough: foveate. Metascutellum: present as a smooth strip. Plical carina: absent. Lateral propodeal carinae: closely approximated medially. Perimeter of lateral propodeal area: foveate. Sculpture of lateral propodeal area: granulate; smooth. Sculpture of metasomal depression: radially striate; smooth. Propleural epicoxal sulcus: absent. Postacetabular sulcus: foveate. Mesopleural epicoxal sulcus: comprised of foveae. Intercoxal space: narrow, cells of posteacetabular and mesopleural epicoxal sulci confluent ventrally. Number of episternal foveae: 2. Prespecular sulcus: present, not extending to mesopleural pit. Paracoxal sulcus in ventral half of metapleuron: foveate. Metapleural epicoxal sulcus: comprised of elongate foveae anteriorly, absent posteriorly. Metapleural sulcus: extending anteriorly from metapleural pit as a smooth furrow. Posterodorsal metapleural sulcus: foveate, interrupted medially.

Metasoma. Color of metasoma: T1-S1, anterior T2-S2 yellow to pale brown, otherwise brown to black. Horn on T1 in females: absent; Sculpture of T1: longitudinally striate. Sculpture of T2: weakly striate posterior to transverse sulcus. Sculpture of T3-T6: uniform coriaceous microsculpture. T6-T7: located ventral to T4-T5, not visible in dorsal view. Sculpture of S1: longitudinally striate. Sculpture of S2: weakly striate posterior to transverse sulcus. Sculpture of S3-S6: uniform coriaceous microsculpture.

Variation. We observed notable variation in the degree of development of two characters. The microsculpture of the lateral propodeal area can be distinctly granulate ( Figures 10 , 21 ) or mostly smooth ( Figure 16 ), and sculpture of the metasomal depression varies from radially striate ( Figure 21 ) to mostly smooth ( Figure 16 )

Material examined.

Holotype, female: MEXICO: 20.622390N, 101.015655W, Santa Cruz de Juventino Rosas , Guanajuato, 18.V.2018, reared from Bagrada hilaris egg, FSCA 00033238 (deposited in FSCA) . Paratypes: (9 females, 3 males) MEXICO : 1 female, 2 males, FSCA 00090587-00090588 (CEAM); FSCA 00033237 (FSCA). UNITED STATES : 8 females, 1 male, FSCA 00090463 (CNCI); FSCA 00033127 (FSCA); USNMENT01335975-01335981 (USNM).

Diagnosis.

It should be noted that our diagnosis is presented without full knowledge of the diversity of Nearctic Idris and additional comparison to the images, description, and sequence data here provided may be necessary to confirm the species identity. From the material that we have examined, Idris elba can be identified by the combination of the following characters: netrion sulcus complete and dorsally terminating ventral to the anterior thoracic spiracle; pronotal suprahumeral sulcus absent; pronotal cervical sulcus absent; episternal foveae arranged along a line between the mesopleural pit and the dorsal apex of the acetabular carina; paracoxal sulcus comprised mostly or entirely of foveae in the ventral half of the metapleuron; metapleural sulcus absent posterior to the metapleural pit; lateral propodeal area without rugae or longitudinal striation; T1 in females without horn; T6-T7 located ventral to T4-T5.

Two distinct characters are found in I. elba and numerous other species of Nearctic Idris , the color pattern of a dark body with a distinctly lighter T1/S1 and anterior T2/S2 ( Figures 3 , 5 - 7 , 20 , 21 ), and the form of the metasoma in which T6-T7 are oriented vertically and are largely obscured from dorsal view ( Figures 20 , 21 ). Among the described species of the Nearctic region, I. howardi is morphologically closest to I. elba and exhibits both traits. Idris howardi can be separated by the striate lateral propodeal area ( Figure 20 ), the ventral portion of the paracoxal sulcus expressed as a simple furrow ( Figure 11 ), and the small size of foveae of the netrion sulcus (compare Figures 8 , 9 ). The absence of rugae or striae in the lateral propodeal area is very useful for diagnosing I. elba (compare Figures 10 - 19 ) but can be found in at least one other species from the region. This species can be separated by the paracoxal sulcus taking the form of a smooth furrow in the ventral half of the metapleuron, the episternal foveae arranged perpendicular to a line between the mesopleural pit and the dorsal apex of the acetabular sulcus ( Figure 14 ) and the foveae of the metanotal trough forming a continuous line above the metascutellum ( Figure 17 ). In female specimens of I. elba , the metascutellum interrupts the line of foveae across the metanotal trough ( Figure 16 ).

We encountered one other species with the ventral portion of the paracoxal sulcus comprised of cells ( Figure 12 ), and this species can easily be separated by the presence of distinct pronotal cervical and pronotal suprahumeral sulci on the lateral pronotum ( Figure 12 ). We emphasize the utility of mesosomal sulci for future taxonomic studies, which exhibit an exceptional diversity of form in Idris . One remarkable species from the mid-Atlantic USA features a netrion sulcus that terminates anterior to the anterior thoracic spiracle ( Figure 13 ). Within Platygastroidea this unusual form is known to us only from Nixonia Masner ( Nixoniidae ) ( Mikó et al. 2007).

Etymology.

The epithet “elba” is an arbitrary combination of letters that is to be treated as a noun in apposition.

Comments.

It is our opinion that the description of a new species from a genus as large and unexplored as Idris outside of the context of a thorough revision generally should be avoided. In the case of Idris elba , we justify our treatment based on the following: First, we are confident that I. elba has not been described previously from the Nearctic region. Idris elba clearly does not belong to the I. melleus species group treated by Masner and Denis (1996) based on the characters they presented, including "head moderately to remarkably large relative to the mesosoma and metasoma", and "propodeum canaliculate (except in I. pulvinus )". Images of all other species from the Nearctic are available via the online image database Specimage (specimage.osu.edu), provided by Norman Johnson (The Ohio State University) and Talamas et al. (2017). Based on these images, Idris elba can be separated from all described Nearctc species outside of the Idris melleus group by the smooth lateral propodeal area, foveate mesoscutal humeral sulcus, and T6-T7 located ventral to T4-T5. Second, we considered the possibility that I. elba is an adventive species, given that the phenomenon of adventive populations of parasitoids following their invasive hosts is now well documented and has occurred with bagrada bug in North America ( Ganjisaffar et al. 2018). We contend that this is highly unlikely because some specimens of I. elba were collected in New Mexico in 2008 (Sandoval Co.), two years prior to the first detection of B. hilaris in this state ( Doña Ana Co.) ( Bundy et al. 2012). Last, the host association of Idris with bagrada bug eggs is of agricultural consequence with implications for the ability of parasitoids to shift between phylogenetically distant hosts ( Araneae and Hemiptera ), and thus there is an immediate need to formally refer to this species. Revising the species of Nearctic Idris is a project requiring years of work and for which resources are not currently available. This situation exemplifies the need for a pre-existing taxonomic framework for parasitoid Hymenoptera , including taxa where the economic importance is not obvious. To that end, this publication may provide impetus for taxonomic revision of Nearctic Idris .

Figures

Figures 1 - 5. 1 unparasitized egg of B. hilaris 2 egg of B. hilaris from which I. elba emerged 3 Idris elba, holotype female (FSCA 00033238), lateral habitus 4 Idris elba paratype female (FSCA 00090587) fore and hind wings, dorsal view 5 Idris elba, paratype male (FSCA 00033237), lateral habitus. Scale bars: in millimeters.

Figures 6, 7. 6 Idris howardi, lectotype female (USNMENT 00989875), head, mesosoma, metasoma, lateral view 7 Idris elba, holotype female (FSCA 00033238), head, mesosoma, metasoma, lateral view. Scale bars: in millimeters.

Figures 8, 9. 8 Idris howardi, lectotype female (USNMENT 00989875), head and mesosoma, anterolateral view 9 Idris elba, holotype female (FSCA 00033238), head and mesosoma, anterolateral view. Scale bars: in millimeters.

Figures 10 - 15. 10 Idris elba, holotype female (FSCA 00033238), mesosoma, lateral view 11 Idris howardi, lectotype female (USNMENT 00989875), mesosoma, lateral view 12 Idris sp., female (FSCA 00090464), mesosoma, lateral view 13 Idris sp., female (FSCA 00033145), mesosoma, lateral view 14 Idris sp., female (FSCA 00090465), mesosoma, lateral view 15 Idris sp., male (FSCA 00090467), mesosoma, lateral view. Scale bars: in millimeters.

Figures 16 - 19. 16 Idris elba, paratype female (FSCA 00090463), mesosoma, posterolateral view 17 Idris sp., female (FSCA 00090465), mesosoma, posterolateral view 18 Idris sp., male (FSCA 00090467), mesosoma, posterolateral view 19 Idris sp., (FSCA 00090466), mesosoma, posterolateral view. Scale bars: in millimeters.

Figures 20, 21. 20 Idris howardi, lectotype female (USNMENT 00989875), mesosoma and metasoma, dorsolateral view 21 Idris elba, holotype female (FSCA 00033238), mesosoma and metasoma, dorsal view. Scale bars: in millimeters.