Thyreodon erythrocera, CAMERON, 1886

Gauld, Ian D. & Janzen, Daniel H., 2004, The systematics and biology of the Costa Rican species of parasitic wasps in the Thyreodon genus-group (Hymenoptera: Ichneumonidae), Zoological Journal of the Linnean Society 141 (3), pp. 297-351 : 327-328

11. THYREODON ERYTHROCERA CAMERON

Thyreodon erythrocera Cameron, 1886: 288 . Holotype ♀, MEXICO: Yucatan (BMNH) [examined].

[ Thyreodon erythrocerus Cameron ; Dalla Torre, 1901: 185. Unjustifiable emendation.].

Fore wing length 21.2–22.8 mm; clypeus convex, with apex strongly pointed medially and conspicuously flared outwards; malar space about 0.5 times basal mandibular width; maxillary palp long with second palpomere broadened and flattened; lower face centrally coarsely punctate; frons with a pair of dorsally divergent crests between antennal sockets and with a sharp carina extending from outer rim of antennal sockets upwards, close to and parallel with eye margin; frons centrally weakly rugose; ocelli small, the lateral ocellus separated from eye by about 1.3 times its own maximum diameter; head in dorsal view punctate, with gena rather evenly rounded behind eye, occipital carina strong, its lower end sharp, abruptly in-turned but not reaching hypostomal carina; antenna setaceous, with 59–62 flagellomeres, the 20th slightly transverse, 0.9 times as long as broad, the subapical ones with setae which are shorter than the diameter of the flagellomere. Pronotum short with anterior margin strongly and broadly reflexed, and with posterior margin centrally swollen, with a sharp forward projecting ridge which is separated from the anterior margin by a deep U-shaped groove; epomia weak but discernible on upper part of pronotum; propleuron sparsely punctate, slightly convex, with lower corner flattened but not peripherally impressed; mesoscutum finely punctate, with broad, shallow, reticulated notauli which are confluent posteriorly, inner anterior margin of notaulus forming a low, longitudinal ridge; scuto-scutellar groove very deep, laterally margined by a very strongly raised, simple carina; scutellum punctate, convex; mesopleuron finely and sparsely punctate, without a sharp sternaular impression but with a few isolated foveae; metapleuron finely punctate; propodeum laterally slightly flattened, finely reticulate, rounded and without a ridge above and behind the spiracle; propodeum dorsally reticulate, centrally with a single shallow longitudinal impression. Fore leg of female rather stout, with coxa with a bluntly rounded protuberance behind trochanteral insertion, with 5th tarsomere about 0.8 times as long as preceding two tarsomeres, with tarsal claw long and with close pectinae; hind coxa in profile moderately small, its hind end more or less level with hind end of propodeum; hind femur slender, about 6 times as long as maximally deep; hind tarsus of male with moderately dense, short pubescence ventrally. Fore wing with abscissa of Cu 1a between Cu 1b and 2 m-cu 0.7–0.8 times as long as abscissa of Cu 1 between cu-a and 1 m-cu. Metasoma with tergite I slender, anteriorly distinctly laterally compressed; tergite II, in lateral view, 2.6–2.7 times as long as posteriorly deep. Male with subgenital plate small and convex, covered with dense coarse black hair; claspers quite long, the dorsal distal apex simply obliquely truncate ( Fig. 54 ); aedeagus in profile evenly rounded.

A black species with proximal 0.6 or more of flagellum yellowish white; wings uniformly brownish black infumate.

Remarks: Thyreodon erythrocera closely resembles two sympatric species, T. morosus and T. walkerae , which are also black with black-tipped yellowish white antennae. It differs from T. morosus in having the propodeum, in lateral view, reticulate, and without a longitudinal ridge above and behind the spiracle. Unlike T. walkerae , which has a pronounced transverse mesoscutal crest, T. erythrocera has the anterior part of the notaulus more or less flat. It also differs from T. walkerae in having the lower face coarsely punctate, not coriaceous to rugose.

Biological notes: Thyreodon erythrocera has been reared only in dry forest, once from Eupyrrhoglossum sagra [98-SRNP-9335] among 114 larvae of this species feeding on Chomelia spinosa and 27 feeding on Guettarda macrosperma , and once from Aellopos titan [98-SRNP-5830] out of 1566 caterpillars feeding on Randia spp. , 35 on Guettarda macrosperma and eight on other Rubiaceae (these eight are probably ecological errors for this caterpillar species). T. erythrocera either occurs at very low density on these two species of Sphingidae , or its host is some other as yet unsampled species of caterpillar and these two rearing records represent biological errors. It may be noteworthy that both rearing records are from the same year, perhaps representing a year in which this species invaded the dry forest from the neighbouring dry forest–rain forest interface. Its larval–pupal biology appears to be the same as that of other Thyreodon . The two reared T. erythrocera took 31–38 days from spinning to eclosion, suggesting a rain forest multivoltine biology, despite the two unique dry forest rearing records. However, the holotype is from Yucatan, a region with widespread dry forest.

Material examined: Holotype ♀, MEXICO, Yucatan, Valladolid (Baumer) ( BMNH).

Non-type material: COSTA RICA: Guanacaste Prov.: 2 ♀, Guanacaste National Park, reared as per data listed above (Janzen & Hallwachs) (JHVC); 1 ♂, Santa Rosa National Park, 300 m, vii.1992 ( Pereira ) ( INBio ).

Figures

Figures 53–63. Apex of metasoma and male genital capsule, lateral; 53, T. maculipennis; 54, T. erythrocera; 55, T. whitfieldi; 56, T. laticinctus; 57, T. zitaniae; 58, T. papei; 59, T. morosus; 60, T. schauffi; 61, T. darlingi; 62, T. rufothorax; 63, T. atriventris.