Trogus, PANZER, 1806

Sime, Karen R. & Wahl, David B., 2002, The cladistics and biology of the Callajoppa genus-group (Hymenoptera: Ichneumonidae, Ichneumoninae), Zoological Journal of the Linnean Society 134 (1), pp. 1-56 : 46-47

TROGUS PANZER, 1806

Trogus Panzer, 1806: 80 . Type-species: ( Ichneumon coerulator Fabricius ) = Ichneumon lapidator var. coerulator Fabricius. Monotypic.

Dinotomus Förster, 1869: 188 . Type-species: ( Ichneumon coerulator Fabricius ) = Ichneumon lapidator var. coerulator Fabricius. Designated by Viereck (1914). Synonymized by Dalla Torre (1902).

Autapomorphies. Apical margin of clypeus concave (#4–1).

Species and distribution. After the removal of four species to Holcojoppa (see above, Taxonomy), there are nine described species distributed in the Palearctic and the New World.

Biology. Trogus is perhaps the biologically bestknown of the Callajoppa genus-group . Several species are common parasitoids of familiar swallowtails, notably T. lapidator (Fabricius) on Papilio machaon (e.g. Kaltenbach, 1874; Morley, 1901) and T. pennator (Fabricius) on P. polyxenes , P. glaucus L., and Eurytides marcellus (Cramer) , among others ( Heinrich, 1962; Feeny et al., 1985; Damman, 1986). Most species have been reared, some of them hundreds of times, and all reliable reports are from the papilionid genera Papilio and Eurytides . There is some variation among Trogus species in degree of polyphagy. Trogus pennator attacks some 10 species on nine food-plant families; T. lapidator attacks at least five swallowtails on three plant families ( Heinrich, 1962; Mitchell, 1979, 1983). Apparently more specialized are T. violaceus (Mocsáry) on Papilio hospiton and P. machaon ( Prota, 1962; M. Shaw, pers. comm.), T. flavipennis Cresson on P. multicaudatus Kirby (two records [CNCI, DNHC]), T. edwardsii Cresson on P. eurymedon Lucas ( Heinrich, 1962) , T. thoracicus Cresson on Eurytides epidaus (Doubleday) and E. philolaus (Boisduval) (D. Janzen, pers. comm. [JHIC]), and, less certainly, the poorly known T. pompeji (Kriechbaumer) on P. scamander Boisduval (two specimens [NHML]). All are larval–pupal parasitoids; T. pennator successfully attacks hosts as young as the first instar (KRS, pers. obsv. in field and laboratory).

None of the records of nonpapilionid hosts for Trogus species merits attention. In collections, we have seen Apatura iris (Nymphalidae) pupal remains placed with a specimen of Psilomastax misidentified as T. lapidator , and a specimen of the latter placed with pupal remains labelled as ‘ Argynnis’ but clearly those of a Papilio ; we thus have very little confidence in isolated records. Early published reports from the nymphalids Vanessa atalanta (L.), V. cardui (L.), A. iris , and Argynnis pandora (Denis & Schiffermüller) and the arctiid Pyrrharctia isabella ( Howard, 1889; Morley, 1901, 1903; Bischoff, 1915; Schmiedeknecht, 1930) have neither been repeated in recent years nor can they be traced to materials in collections.