Perilampus sirsiris (Argaman)

Figs 6, 7, 24 C

Ichneumon cyaneus Brullé, 1846: 21 (Plate V, # 4). Type locality: USA, “ Carolina ”. Type material: Holotype. “Carolina”. (Female Paris EY 35408, MHNH) (images examined).

Perilampus cyaneus Dalla Torre, 1898: 355 (new combination?).

Perilampus hyalinus Viereck, 1910: 647 (subjective synonym P. cyaneus ?, cited by Peck 1963).

Taltonos sirsiris Argaman, 1990: 15 . Replacement name, Perilampus cyaneus Brullé (nec Fabricius 1798).

Perilampus sirsiris Darling, 1996: 113 (Taltonos, subjective synonym of Perilampus).

Perilampus eucyaneus Özdikmen, 2011 . Unnecessary replacement name.

Material examined.

Canada: 4 females, 8 males. USA: 17 females, 11 males. (Suppl. materials).

Description.

Female (Fig. 6). Length: 2.5–4.5 mm. Color: head iridescent greenish blue or violet, usually without black coloration between lateral ocellus and frontal carina; mesosoma, and metasoma iridescent greenish blue or violet; clypeus ventral margin black (Fig. 6 I); antenna with scape and pedicel weakly iridescent greenish blue or violet, flagellum brown or black, lighter ventrad and distad.

Head (Fig. 6 G – J): in dorsal view transverse, width slightly greater than twice length, HW / HL 2.1–2.2. Frontal carina: in anterior view straight to weakly sinuate below midlevel of eye; in dorsal view gradually narrowed V shape around median ocellus, FC / MOD 1.5–1.9; distance from lateral ocellus short, FCLO / LOD 0.6–0.7. Scrobal cavity (Fig. 6 H): in anterior view wide, SW / HW about 0.5. Ocelli (Fig. 6 G): a line between anterior margin of lateral ocelli reaching anterior margin of median ocellus. POL / OOL 1.7–2.0. Ocellar ratios LOD: POL: OOL: LOL 1, 3.1–3.3, 1.6–1.9, 1.0–1.1. Vertex: with strong to weak transverse striations, without large piliferous punctures. Parascrobal area: in lateral view gradually narrowed towards lower eye margin; width narrow, PSW / EL about 0.3; sculpture strongly to weakly striate, or rarely smooth, without large piliferous punctures. Gena (Fig. 6 J): entirely or mostly striate along outer eye margin with narrow and short smooth area, striate behind. Malar space: MSL / EH 0.2–0.3. Lower face (Fig. 6 H, I): with setae sparse laterad torulus, and usually sparse below. Clypeus (Fig. 6 I): CW / CH 1.3–1.4; ventral margin concave; setae evenly distributed, or with small bare area without setae medially.

Mesosoma (Fig. 6 B – F, K, L): Lateral panel of pronotum: slightly narrower than prepectus, LPP / PPT 0.7–0.8; without flange or with small rounded flange below level of mesothoracic spiracle in posterior oblique view (Fig. 6 D, E). Mesofemoral depression: usually smooth, weakly imbricate, or rugulose (Fig. 6 L). Mesoscutum: punctures angulate, with narrow or slightly wide and weakly coriarious interspaces (Fig. 6 B); lateral lobe weakly punctate with coriarious or smooth interspaces (Fig. 6 C), or smooth, along notaulus; parascutal carina usually angulate, rarely steeply curved, often weakly flanged (Fig. 6 F, arrow). Mesoscutellum: apex with inner margins gradually or abruptly diverging (Fig. 6 K); punctures angulate, with narrow or slightly wide and weakly coriarious interspaces. Axilla: in lateral view imbricate dorsad and carinate or rugose-areolate ventrad. Axillula: smooth dorsad. Fore wing: stigma small, 2.0–2.5 × as wide as postmarginal vein.

Male (Fig. 7). Length: usually smaller, 1.7–3.8 mm. As in female, except: Color: mesonotum sometimes with weak cupreous iridescence. Frontal carina (Fig. 7 C): distance from lateral ocellus shorter, FCLO / LOD 0.3–0.4. Scape (Fig. 7 F. G): pits sparse, covering about 0.4 × scape length.

Diagnosis.

Perilampus sirsiris and P. arcus are the only Nearctic species with steeply curved or angulate parascutal carina often with a flange (Fig, 6 F, 7 B, 20 E, 21 B cf. Figs 8 J, 9 B). Perilampus sirsiris differs from P. arcus in usually having an angulate parascutal carina (Fig. 6 F cf. Fig. 20 F), a flat lateral panel of pronotum or with a small rounded flange in posterior oblique view (Fig. 6 D, E cf. Fig. 20 D), and the male scape with sparsely pitted surface distad (Fig. 7 F, G cf. Fig. 21 G, H).

Distribution

(Fig. 25 C). Throughout USA and southern Canada: Canada (Ontario, Quebec, British Columbia), USA (Arkansas, Florida, Kansas, Maryland, Missouri, Montana, Oregon, Texas, West Virginia).

Host association.

Perilampus sirsiris is a hyperparasitoid, a parasitoid of dipteran and hymenopteran parasitoids of Lepidoptera, rarely of hymenopteran parasitoids of argid sawflies. Hosts: Tachinidae ( Diptera) from Hyphantria cunea (Drury) ( Erebidae) and Malacosoma disstria Hübner ( Lasiocampidae). Sarcophagidae ( Diptera) from Neophasia menapia (C. & R. Felder) ( Pieridae). Braconidae ( Hymenoptera). Cotesia hyphantriae (Riley) from Hyphantria cunea (Drury) . Ichneumonidae ( Hymenoptera) from Arge sp. ( Hymenoptera).

Variation.

There is a rare variant from Manitoulin Island, Ontario, a male (ROME 152661) which has a wide bare area without setae on the clypeus similar to P. monocteni, but confirmed as P. sirsiris by the steeply curved parascutal carina and COI and ITS 2.

Remarks.

The descriptions of P. sirsiris provided in Brullé (1846) and Argaman (1990) are insufficient for species discrimination, but the holotype of this species is intact (MNHN). The images of the holotype sent by the MNHN (Fig. 24 C) provided sufficient morphological details for associating the holotype with one of the common Nearctic species based on the key and redescription provided herein. Argaman’s descriptions of color and pronotal flange (“ Head and sides of thorax golden-green to bluish ”, “ with a triangularly acute lobe opposite to upper top of prepectus ”) do not match the holotype of P. cyaneus . Due to the dubious nature of the type specimen listed in his annotated checklist, where he states that the holotype is in his private collection (Argaman 1991), Argaman clearly did not examine Brullé’s type. It is likely that the “ Types ” in Argaman’s checklist represent the specimens he regards as conspecifics, rather than the actual extant types (Darling 1996). We examined two additional NHMH specimens from Jalisco, Mexico misidentified as P. sirsiris by Argaman (1991), identified herein as a female P. hyalinus (ROME 200751) and male P. ute (ROME 200740). The only other literature record of P. sirsiris is Graenicher (1909), which mentions the preference of P. hyalinus and P. sirsiris for flowers of Erigeron canadensis Linnaeus. However, given the poor description of P. sirsiris by Brullé and the absence of an indication that Graenicher had examined the type, it is unclear if the observed species was indeed P. sirsiris .

The steeply curved or angulate parascutal carina often with a flange (Figs 6 F, 7 B) is one of the key diagnostic features of P. sirsiris . Perilampus arcus (Figs 20 E, 21 B) also has a similarly modified parascutal carina, but the phylogenetic placement of the two species (Fig. 1) suggests convergent evolution within the P. hyalinus species complex. This state is also widely distributed in other species of Perilampidae, including some species of the P. platigaster species group, and is almost certainly derived independently. Both genes and species delimitation methods support P. sirsiris (Fig. 1, Suppl. material 5) and there are 10 BINed specimens on BOLD (AEM 7685) from throughout the range of this species (Quebec to Texas) and one specimen (ROME 185904, Missouri) with a COI sequence reared from Hyphantia cunea .

Perilampus sirsiris parasitizes dipteran and hymenopteran parasitoids of Lepidoptera, which feed on the leaves of deciduous trees. Interestingly, the hosts of P. sirsiris also include sarcophagid parasitoids of the pine butterfly, N. menapia ( Pieridae) — this is the only species associated with pines other than P. neodiprioni, the hypothesized sister species of P. sirsiris (Fig. 1) (see Remarks for P. neodiprioni below).