Hyposoter didymator ( Thunberg, 1824 )

Galsworthy, Anthony, Shaw, Mark R. & Haraldseide, Håkon, 2023, A key to European species of Hyposoter Förster, 1869 (Ichneumonidae: Campopleginae) with descriptions of 18 new species, and notes on all included species, Zootaxa 5290 (1), pp. 1-73 : 40

Hyposoter didymator ( Thunberg, 1824)

Ichneumon didymator Thunberg, 1824 : holotype ♀ in University Museum , Uppsala, Sweden, examined by Horstmann.

syn. Ichneumon rotundator Thunberg, 1824 : Roman (1912)

syn. Campoplex ruficincta Gravenhorst, 1829 : Roman (1912)

syn. Anilastus schmiedeknechti Smits van Burgst, 1913 : Aubert (1966a)

syn. Trophocampa nigrata Kiss, 1926 : Horstmann (2009)

Roman (1912) referred to a ‘single well preserved specimen’ in the Thunberg collection. Townes et al. (1965) designated what is presumably the same specimen as ‘type’.

This is a common and well-known species. Horstmann placed it in the key in his section covering species with predominantly or completely black metasomata as well as in that covering species with red on the metasoma. Specimens from most of Europe which we have seen always have a considerable amount of red on the metasoma, usually involving the whole of at least one tergite. However, a long series from Norway is much darker, with some specimens showing no red at all. This may perhaps be a boreal form of the species.

The most likely species with which it might be confused is Hyposoter barrettii : while didymator always has a smooth or only faintly sculptured speculum, barrettii has some fine striae extending across it. In the female the broad emarginate notch in the seventh sternite of barrettii is entirely lacking in didymator . The dark banding on the hind tibia of didymator is also more sharply defined and broader than in barrettii .

Rearing records are very numerous from a wide variety of lepidopteran hosts, including Geometridae , Lasiocampidae , Noctuidae , Notodontidae , Papilionidae and Pieridae . Shaw et al. (2016) provide a long list of species. In addition to these, we have found among the previously unidentified NMS material 2♀ reared from Lithomoia solidaginis (Ḩbner) in Poland, 1♀ from Noctua pronuba (Linnaeus) in Austria, 1♀ marked as reared from imported Spodoptera litura (Fabricius) in the UK, and 1♀ from Trachea atriplicis (Linnaeus) in France. In NHMUK there are the following reared specimens, all from Noctuidae : ex Anarta myrtilli (Linnaeus) (1♁), “ H. neglecta ” probably = Xestia castanea (Esper) (1♁), Xestia agathina (Duponchel) (2♁), Plusia on potatoes (2♁ 1♀), on lucerne (1♁ 3♀), and on beans (1♁), Spodoptera littoralis (Boisduval) on lucerne (3♁ 3♀), Helicoverpa armigera (Ḩbner) on lucerne (3♀) and on tomato (1♁), Heliothis peltigera (Denis & Schiffermüller) on weeds (2♁ 1♀), Spodoptera exigua (Hübner) on alfalfa (2♀), on maize (1♁ 1♀), and on lucerne (1♁ 1♀), and Cucullia gnaphthalii (Hübner) (1♁, 1♀). There are many more records, though of uncertain authenticity, in the literature. We have seen specimens from the UK, the Netherlands, France, Belgium, Norway, Sweden, Austria, Spain, Hungary, Poland, Greece and Cyprus. The species has been recorded widely in the literature across Eurasia from Ireland to Russia and Tajikistan. It was introduced to Australia and New Zealand. We have seen specimens taken in every month from May to October, with numbers fairly evenly spread through June to September. This no doubt reflects the diversity of available hosts for this plurivoltine species.

Three specimens from the third author’s collection were barcoded (BOLD Sample IDs CollHH1222, 1223 and 1224).