Slaterocoris Wagner

Schwartz, Michael D., 2011, Revision And Phylogenetic Analysis Of The North American Genus Slaterocoris Wagner With New Synonymy, The Description Of Five New Species And A New Genus From Mexico, And A Review Of The Genus Scalponotatus Kelton (Heteroptera: Miridae: Orthotylinae), Bulletin of the American Museum of Natural History 2011 (354), pp. 1-290 : 72-78

Slaterocoris Wagner

Slaterocoris Wagner : 1956: 280 (orig. desc.); Kelton, 1968, 1121 (revision); Knight, 1970: 233 (revision); Henry and Wheeler, 1988: 448 (catalog); Schuh, 1995: 196 (catalog); Asquith, 1991: 13, 16 (disc.); 1994: 1, 6, 8–9, 12–13 (disc.); Forero, 2008: 152, 157–158 (disc.).

TYPE SPECIES: Capsus stygicus Say, 1832 (orig. design.).

Amulacoris Carvalho and China, 1959: 69 (orig. desc.); Schuh, 1995: 80 (catalog). NEW SYNONYMY.

TYPE SPECIES: Jornandes subalbicans Distant, 1893 (orig. design.).

Guerrerocoris Carvalho and China, 1959: 70 (orig. desc.); Schuh, 1995: 114 (catalog). NEW SYNONYMY.

TYPE SPECIES: Jornandes punctatus Distant, 1893 (orig. design.).

REVISED DIAGNOSIS: Recognized by the entirely black head, except in Slaterocoris clavatus and S. maculatus where pale patches are usually present on the temporal areas. Thus distinguished from Scalponotatus , which has the lateral margins of the carina or the entire carina usually pale, except in Scalponotatus howdeni and S. lagunensis , where the entire carina is black. Also distinguished from Josephinus , where the frons or the entire head is usually pale; except in J. albicornis , in which the head is mostly black, except for the pale lateral margins of the carina. Slaterocoris is unequivocally recognized by the male genitalia with usually small, curved tergal process on right side of midline; left paramere with narrow distal region and small rounded apex; right paramere with large, ventrally projecting spines; endosomal spicule with large, sometimes bifurcate dorsal lobe. Slaterocoris clavatus is the only species that does not completely manifest all the male genitalia features (right paramere with apical spines dorsal and dorsal lobe small); however, it does have the coloration, dorsal sculpturation, vestiture, and head structure found in all other species of Slaterocoris . The anteromedial margin of the dorsal labiate plate in the female genitalia of S. clavatus is more sclerotized than in other species of Slaterocoris . Where known, all species feed on foliar structures of common Asteraceae and are distributed in open habitats across North America, extending to and including southern Mexico.

REDESCRIPTION: Male: Body moderately small to large, ovate to elongate, always macropterous; hemelytron long, costal margin nearly straight; length 2.70–7.00, width across pronotum 1.10–1.93. COLORATION: Shining black; including vertex and venter; rarely, if head pale then clypeus, frons dorsally and on posterior margin black; antenna usually with portions of segments pale, sometimes all segments variously pale yellow or entirely black; legs usually with tarsomeres pale yellow with segment III black, sometimes only apex of segment III pale or all segments black; tibia pale yellow, sometimes orange, red or black, usually with apex black; femur usually black and apically pale or with variable proportions basally pale and distally black, sometimes entirely red or black, rarely basally pale and dark apically, or femur entirely pale; coxa predominantly black; rarely mostly or entirely pale; evaporative area and peritreme of metepisternal scent gland black; membrane of hemelytron darkly infuscate; rarely middle of membrane broadly hyaline. VESTITURE: Ranging from sparsely distributed, short and recurved dark setae, to moderately dense, long and erect black setae, to densely distributed, reclining or erect, silvery white, golden brown, or black simple setae (pl. 4); sometimes with matted setae with recurved apices; antenna with moderately densely distributed, reclining setae with length usually less than diameter of antennal segments, sometimes length greater than antennal diameter; sometimes anterior margin of pronotum with scattered, long, erect, black, bristlelike setae; tibiae with black spines, sometimes pale brown; membrane of hemelytra with densely distributed microtrichae. DORSAL SCULPTURATION: Variously rugulopunctate; calli slightly produced; scutellum transversely so; pronotal disc with discrete moderate punctures (fig. 36C); hemelytron surface of large punctures merging with rugosity or reticulation of variable intensity (figs. 31A, 36B, D). STRUCTURE: Head hypognathous, vertical, in lateral view (fig. 36A), clypeus, maxillary and mandibular plates slightly produced; frons gently rounded, in lateral view (figs. 14B, 36C), usually smooth (figs. 14A, 36A), sometimes slightly roughened (figs. 31A, 56A); vertex depressed or flattened anterior of prominent basal carina (figs. 36C, 56A); posterior margin of head on same plane with posterolateral margin of eye; anterior margin of pronotum not overlapped by posterolateral margin of eye; antenna with segments III and IV narrow; length of segment II usually longer than width of head across eyes, sometimes length less than head width; labium reaching apex of mesosternum to middle of middle coxa. Pronotum broadly trapeziform, in dorsal view; anterolateral and humeral angles and posterior margin broadly rounded; calli smooth or finely punctate, broadly rounded, slightly produced; mesoscutum obscured by pronotum. Hemelytron with deflected cuneus. Metepisternal spiracle elongate, evaporative area on tergum elongate and triangular dorsally; external metepisternal scent gland area with ostiole flattened, attenuate dorsally, and elevated; evaporative area wide, triangular, and spanning width of metepisternum, peritreme and evaporative surface with evaporative bodies (figs. 14D, 20E, 37A, 56B, 59C, 67A). Pretarsus with base of claw smooth, claw broadly curved; pulvillus moderately large, not extending beyond medial curve of claw; parempodium fleshy, apically convergent (figs. 20F, 37B, 56C). MALE GENITALIA: Pygophore: Dorsal margin of aperture with variously modified tergal process usually on right side of midline, sometimes just right of midline; tergal process either solitary or bifurcate, small or large; ventral margin of aperture nominally rounded in posterior view, with obvious crease or notch medially; subgenital plate (or cup-shaped sclerite of Konstantinov, 2003; Forero, 2008) with posterior edge not meeting flush with ventral margin of aperture, but ventral of it, and somewhat recessed anteriorly (fig. 39F); paramere insertions with right socket situated slightly dorsal to left socket. Phallotheca: Convoluted, aperture sinuously open apically, continuing basally on right side; left dorsal side with variously shaped U-shaped notch (figs. 39E, 55H), sometimes with second aperture (fig. 65F). Endosoma: With one bifurcate spicule situated dorsal to base of sclerotized region of ductus seminis; base of endosomal spicule attached directly to membrane; without recurved basal keel; bifurcate portions of spicule denoted as dorsal and ventral lobes; dorsal lobe shorter than ventral lobe, usually marginally serrate or bifurcate; bifurcate portions denoted as medial and lateral rami; ventral lobe longer than dorsal lobe, narrow and recurved distally, sometimes bifurcate distally (fig. 39A–D). Left paramere: L-shaped; basal region unmodified from remainder of paramere body, sensory lobe at most moderately produced, shaft narrowed and with broad to narrow pointed apex (fig. 39G, H), rarely bifurcated (fig. 16C, D), but never with apical cleft or mitten shaped (fig. 4C, D). Right paramere: Species specific, variously spinose and produced in apical, subapical or medial, and basal regions, all spines projecting from ventral margin (figs. 15, 17, 28, 32J–O, 38, 41, 51, 64I–L).

Female: Coloration, vestiture, and structure as in male, except vertex wider, eye smaller, antennal segment II narrower, and costal margin usually more strongly convex. ABDOMEN: Subgenital plate: Triangular, broadly shield shaped with blunt apex; base of ovipositor located anterior to longitudinal midpoint of abdomen. GENITALIA: First gonapophysis: Overlap at apices variable, usually left overlaps right (fig. 23A, B), sometimes right overlaps left (fig. 40A, B); size at overlap variable. Vestibulum: Anteroventral margin of anterior wall sclerotized medially, spanning lateral margins of bursa copulatrix (fig. 40A), sometimes slightly incised medially (fig. 23A), or with deeper more obviously sclerotized ventral dimension (fig. 58A). Left first gonapophysis: Composed of two sections—anterior section strongly produced and variously modified (fig. 23B, 40B, 47B, 53B, 70B), posterior section elongate, slightly produced medial to first ramus and larger than corresponding section of right first gonapophysis; mediodistal area prominent, obviously larger than on right first gonapophysis; dorsal surface concave or protuberant; size of apex variable. Ventral labiate plate: Base with variable width, either moderately wide or wide; posterior margin strongly sclerotized and prominently produced into vulva (fig. 40A), sometimes cleft apically (fig. 23A). Dorsal labiate plate: Area ventral and anterior to rings with microtrichae; lateral margins strongly infolded, including D-shaped sclerotized rings; paired medial sclerites of greater width than length and dorsal anteromedial margin and dorsal region membranous (fig. 70A), except in S. clavatus . Second gonapophysis: Anteromedial surface slightly or strongly produced (fig. 70C). Interramal sclerite: Dorsomedial margin with anterior margin variably outpocketed; medial region platelike, variously overlapped by adjoining margin of lateral sclerites; posteromedial surface with variably produced sclerotization abutting ovipositor bulb (figs. 23D, 40D). Interramal lobe: Strongly sclerotized, broadly bulging basally (posteriorly) and tapered to single or rarely bifurcate distal (anterior) projection(s) that curve medially; margins of interramal lobe densely covered with numerous, moderately long, platelike and acute microtrichae; with dorsal (basal or posterior) insertion usually with membranous attachment; dorsomedial (posteromedial) and ventral (anterior) margins with serrate lobes of variable length and size (figs. 53D, 70D).

DISCUSSION: The type species of Amulacoris ( subalbicans ) and Guerrerocoris ( punctatus ) are herein considered to species of Slaterocoris , thus making both genera junior synonyms of Slaterocoris . See the discussions below under each nominal species treatment.

Some features of the female genitalic morphology require discussion. For the members of the flavipes species group the ventral labiate plate with a strongly produced and medially cleft ventral projection (59-3) was mapped on the cladogram ( fig. 2 ) as a homoplasious synapomorphy, because one species of the group, S. longipennis , is polymorphic for this character. The cleft medial portion of the ventral labiate plate was not observed in any species of Slaterocoris . Two of the species in this group, flavipes and longipennis , also have the ventral medial margin of the anterior wall cleft (57- 4). Perhaps both indentations indicate a fusion or suture of the left and right sides of the first gonapophyses.

The paired, medial sclerotized plates of the dorsal labiate plate with width greater than length (60-2) are more widely separated from each other in Slaterocoris than in Jornandinus and Josephinus . The ventral labiate plate in Ficinus and Jornandes sometimes has a narrow ventral projection into the vulva ( Schaffner and Schwartz, 2008); in all species of Slaterocoris this region is always broadly projecting. The most posterior portion of the left first gonapophysis is clearly separated from the more anterior region in the former genera (cf. ibid.: 14, 41, figs. 8B, 19C), whereas in Slaterocoris the posterior portion is not prominent.

The asymmetrical first gonapophyses in Slaterocoris show some novel conditions. In the breviatus group and S. tanydexios , the right side overlaps the left. The left side overlaps the right in the rest of the species. The size of the right gonapophyses is variable for species with this latter condition. The right gonapophyses is small in the argenteus (except S. digitatus ) and hirtus groups and S. ambrosiae . The right gonapophyses in the croceipes , flavipes, punctatus (except S. simplex ) groups, and S. robustus is only slightly smaller than the left first gonapophyses. All species of Slaterocoris lack an inflatable lobe on the apex of the left first gonapophysis, as seen in Ficinus sagittarius Distant, 1893 , Jornandes cruralis Distant, 1893 , some Lopidella species (personal obs.), and Cyllecoris histrionics (L.) ( Pluot-Sigwalt and Matocq, 2006).

The anteromedial part of second gonapophyses, ventral to the ovipositor bulb, is variably developed in Slaterocoris . About half the species have this region strongly or very strongly produced, while in the remaining species it is slightly produced as is the case with Josephinus and Scalponotatus . Compared with Ficinus (cf. Schaffner and Schwartz, 2008: 14, fig. 8C) and Jornandes (cf. ibid.: 41, fig. 19A, B), Slaterocoris does not have the thickened, dorsomedial (or posteromedial) region of the interramal sclerite strongly produced anteriorly (ventrally). Only S. simplex (fig. 66B) with a narrow lobe (68-1) comes closest to this morphology. Otherwise the medial region of the interramal lobe is at most strongly sclerotized as a plate in the same plane as the reminder of the lobe, appearing as an outpocket (68-2; e.g., S. tanydexios , fig. 70D). The ventral medial portion of interramal sclerite is strongly sclerotized with an obscure junction adjacent to the lateral regions in Jornandinus . Although the medial region is strongly sclerotized (64-1) in Slaterocoris , there is always a obvious junction between the medial and lateral regions (fig. 40D).

BIOLOGY: Almost all the plant records associated with species of Slaterocoris are Asteraceae species, either herbaceous or woody, perennial or sometimes annual. The putative hosts gleaned from label data, previous descriptions, regional compilations (see Methods and Materials), and a few ecological studies (see below) are listed in table 4. I have distinguished two levels of host utilization on asteraceous plants. A plant species was construed as either a major or minor host plant based on the number of specimens collected on a particular plant species at a single locality as well as the preponderance of collecting events where specimens were collected from the same plant. For the major Asteraceous host plants, table 5 presents a list of the species of Slaterocoris and Scalponotatus maturus that utilize them.

The life history of Slaterocoris pallipes on Baccharis halimifolia has been studied in substantial detail, with observations from most of the distributional range of the species ( Wheeler, 1981). The seasonality and feeding strategies of S. atritibialis , S. breviatus , and S. stygicus were ascertained in two studies investigating Miridae inhabiting goldenrod, Solidago spp. , in southeastern Ontario ( Reid et al., 1976) and central New York ( Messina, 1978). The conclusions reached in the Solidago studies were from a limited portion of the overall range of three species. The phenology and relative abundance of these three Slaterocoris species were roughly similar; only the absolute dates differed ( Reid et al., 1976; Messina, 1978). Slaterocoris atritibialis adults occurred earlier and were less abundant than the later occurring and more abundant S. breviatus . Slaterocoris stygicus was virtually absent in the Ontario study, but in New York, matched the phenology of S. breviatus , albeit with lower abundance. These three species of the S. breviatus group, although not referenced by specific name, were also included in plant-insect interactions studies of herbivore suites ( Maddox and Root, 1990) and genetic variation of Solidago ( Maddox and Root, 1987) . Contrary to the previous studies, a considerable number of S. stygicus were taken on the annual Ambrosia trifida prior to bloom. Wheeler (2001) reported foliar chlorosis on this host by S. stygicus . The label data are the only guides to the hosts of the two remaining species of the S. breviatus group, S. pallidicornis and S. solidaginis , where unspecified species of Solidago and small herbaceous Artemisia species appear to be hosts (but cf. S. pallidicornis , below) with the bugs clearly present prior to the flowering period of the plants.

Because species of the S. breviatus group are distributed primarily in eastern North America, their life history information may not be entirely transferrable to the genus as a whole. The majority of the other species in the genus are predominantly inhabitants of woody asteraceous shrubs in desert and montane habitat of western North America extending from the Yukon, Canada, to Oaxaca, Mexico. Cognizant of these limitations, we might nonetheless predict that the remaining species of Slaterocoris probably have similar life histories to those of the S. breviatus group. The key features are diapause in the egg stage, activity relatively early in the season, feeding apparently restricted to vegetative plant tissue, and univoltine life cycle. Kraft and Denno (1982) suggested that the strategy for the univoltine, mesophyll feeder, S. pallipes was to utilize the higher concentration of nitrogen in young, early season leaves of B. halimifolia , completing its life cycle prior to the lower foliar nitrogen content of the host in late summer. Wheeler (1981) extended this interpretation of early season utilization of higher foliar nitrogen concentration to the Solidago feeders discussed above.

The life history pattern for the other species of Slaterocoris is roughly similar where label data documenting hosts are available. The aptly named S. ambrosiae utilizes herbaceous and woody perennial species of Ambrosia in the southwestern desert and annual species of the genus in the central plains. It apparently reaches the adult stage and completes mating and oviposition before the bloom period of the hosts. At least two species of the S. hirtus group are exclusively inhabitants of the herbaceous perennial, Silphium perfoliatum , and were collected previous to its main bloom period. Foliar chlorosis was noted on this host as the result of feeding by S. hirtus ( Wheeler, 2001) . The host(s) for the remaining species of this group, S. alpinus , is unknown. The species of the S. apache and S. flavipes groups (10 species) and S. robustus all utilize woody perennials hosts of Artemisia , Chrysothamnus , Ericameria , and to a lesser extent species of Gutierrezia and Tetradymia (see table 5). The bugs are active on the host species of all these genera before the late summer blooming period. The host of S. atratus , a putative member of the S. apache group, is unknown.

Beyond sporadic records noting the collection from asteraceous plants, nothing definitive in known concerning the hosts of the remaining species of Slaterocoris . These eight species are all distributed in Mexico, except for S. digitatus from the Chisos Mountains, Texas. The phenology of the adults of these species is obviously later in the season than all the previous discussed species, from late July to September. Only further investigation with documented hosts will determine whether the Mexican species have a plant-utilization pattern similar to the species distributed in the shrub lands and temperate regions in the United States.

Wheeler (2001, personal obs.) made reference to the attraction of Slaterocoris species to the inflorescence of poison hemlock, Conium maculatum L. ( Apiaceae ), a plant with an open floral system that does not restrict access to nectar and pollen. Reid (1974) determined that the rate of parasitism was 8 % –12 % in S. atritibialis , S. breviatus , and S. stygicus on Solidago in southern Ontario by Hexamermis species (Nematoda: Mermithidae ).

SPECIES RECOGNITION: Black is the predominant color of the body and appendages. Where pale markings exist they are usually important in species recognition. Two punctatus -group species, S. clavatus , S. maculatus , have distinct pale markings near the medial margin of the eye. Two species from different species groups, S. pallipes and S. sparsus , have entirely pale legs. Some species are recognized by various pale markings on antennal segments I or II, as well as the coxae, femora, or tibiae. Dorsal vestiture characteristics facilitate the recognition of several species, e.g., the long, dense, erect or suberect setae of the hirtus group, or the short, sparse setae of the breviatus group.

Variation in the solitary dorsal endosomal spicule is congruent with vestiture and coloration pattern and is important for species recognition. Intraspecific variation in the endosomal spicule was observed during the course of this study in some species and is documented in the illustrations for those species. The most reliable characters for distinguishing species are located on the endosomal spicule and the right paramere. Distinctive features of the dorsal and ventral lobes of the endosomal spicule include the extent of marginal serration, whether the shaft of the distal portions are flat or rounded, and whether the dorsal lobe is further divided into medial and lateral sections. The flavipes group contains species that can be diagnosed based on the endosomal spicule alone, with the dorsal lobe being twisted along its long axis. Two punctatus - group species, S. clavatus (fig. 57A, B) and S. simplex (fig. 65C–E), have autapomorphic endosomal spicule structure. Each species group has a specific formation of the right paramere, that in combination with other characters, allow species recognition. The apache group has a prominent basal lobe, the breviatus group has a roughly radial arrangement of the apical spines, the flavipes group has the apical spines narrowed, and the hirtus group has the apical spines elongate and parallel. Although the left paramere is relatively invariant, the obviously bifurcated apex, will unequivocally allow recognition of S. ambrosiae .

Features of the female genitalia tend to be significant at the generic level. For example, the strongly sclerotized anteromedial margin of the dorsal labiate plate is known only from species of Josephinus . Within Slaterocoris , the conformation of first gonapophyses, with the apex of the right side much larger and overlapping that of the left side will distinguish the breviatus group.

Figures

Fig. 2. One of three most parsimonious cladograms found in 40-taxa analysis for Slaterocoris and outgroups.