Hemichroa crocea (Geoffroy, 1785)

Prous, Marko, Liston, Andrew, Kramp, Katja, Savina, Henri, Vardal, Hege & Taeger, Andreas, 2019, The West Palaearctic genera of Nematinae (Hymenoptera, Tenthredinidae), ZooKeys 875, pp. 63-127 : 63

Hemichroa crocea (Geoffroy, 1785)

Tenthredo crocea Geoffroy in Fourcroy, 1785: 364. Syntype(s) ♀, lost. Type locality: Paris (France).

Tenthredo rufa Panzer, 1799: 72:2. Syntype(s) ♀, lost. Type locality: Germany. Primary homonym of Tenthredo rufa Retzius, 1783.

Hemichroa stigma Stephens, 1835: 56. Syntype(s) ♀, most likely lost. Type locality: Ripley (United Kingdom). Listed in synonymy with Hemichroa rufa (Panzer) by Dalla Torre (1894: 283).

Leptocercus nigriceps Thomson, 1871: 78. Holotype ♀, not examined, in MZLU. Type locality: Skåne (Sweden). Synonymy with crocea by Lindqvist (1954).

Dineura (Leptocera) unicolor Rudow, 1872: 218. Syntype(s) ♀, most likely lost. Type locality: not given [Germany]. Synonymy by Konow (1897: 259).

Dineura americana Provancher, 1882: 292-293. Holotype ♀, not examined, ULQC. Type locality: Chicoutimi (Canada). Synonymy by Ross (1937: 79).

Nematus ardens Zaddach in Brischke, 1883a: 133-134. Holotype ♀, lost. Type locality: Carolath (Siedlisko, Poland). Listed in synonymy by Konow (1905: 49).

Dineura pallida Ashmead, 1890: 15. Holotype ♀, not examined, in USNM. Type locality: West Cliff, Ca. (USA). Synonymy by Ross (1937: 79).

Hemichroa dyari Rohwer, 1918: 170-171. Holotype ♀, not examined, in USNM. Type locality: Woods Hole, Massachusetts (USA). Synonymy by Ross (1937: 79).

Hemichroa (Hemichroa) orientalis Rohwer, 1921: 108-109. Holotype ♀, not examined, in USNM. Type locality: Kumaon, Ramgark (India). Synonymy by Smith (1975: 298).

Hemichroa (Hemichroa) washingtonia Rohwer & Middleton, 1932: 97-98. Holotype ♀, not examined, in USNM. Type locality: Seattle, Washington (USA). Listed in synonymy by Ross (1937: 79).

Description.

Body length: female 5.5-8.5 mm, male 5.5 mm (only one examined). Female ( Figs 98 , 100 ): Orange-red. Black are (more or less): labrum, propleuron, mesopleuron, metapleuron, metanotum, ventral part of mesepistermum, abdominal tergum 1, valvula 3. Coxae, trochanters and femora brown, with variable black markings. Tibiae basally pale (whitish), apically dark. Tarsi dark. Lancet: Fig. 112 . Male ( Fig. 102 ): Head including antennae, and body black, except more or less for tegulae, pronotum, and parts of abdominal terga and sterna. Legs red, except for darkened coxa, more or less trochanters and trochantelli, metatarsus, and apex of metatibia. Penis valve: Fig. 107 .

We have only examined one old male specimen (DEI-GISHym31838), without genetic data, which we think belongs to crocea , because of the similarity of its penis valve to that illustrated by Smith (1975; fig. 4) as crocea , and differences in the penis valves of australis identified by us, using sequence data. This crocea male has its abdomen and parts of the mesoscutum extensively yellow, but completely black antennae, as well as darkened metatarsus and metatibia apex. However, the original descriptions of the males of Hemichroa dyari , pallida and washingtonia ( Rohwer 1918, Rohwer and Middleton 1932), all of which are currently treated as synonyms of H. crocea , indicate that body colouration is variable, and can be as dark as in male australis . The metatibia and metatarsus may apparently also be dark or pale, as respectively described by Rohwer (1918) for males of dyari and pallida . On the other hand, the descriptions of North American crocea males suggest that the antennae are completely dark, as described by Benson (1958) for European males.

Similar species.

See key and notes on australis , above.

Life history.

Host plants: Alnus glutinosa , incana , viridis , Betula pendula , and sometimes Corylus avellana ( Pschorn-Walcher and Altenhofer 2000). Salix is mentioned repeatedly in various works as a host, but no unambiguous original record of feeding by larvae on Salix has been located. Larvae gregarious, and brightly coloured ( Fig. 87 ). Boevé (2015) compared the defensive strategy of crocea and australis larvae. Usually two overlapping generations in the lowlands ( Hopping 1937, Pschorn-Walcher and Altenhofer 2000), but mainly univoltine at subalpine levels ( Kriegl 1964). Whereas the subalpine populations are entirely parthenogenetic ( Kriegl 1964), approximately 3% males were reared in northern Germany ( Pschorn-Walcher and Altenhofer 2000).

Distribution.

Found widely in the Holarctic, from the British Isles, through central and northern Europe ( Taeger et al. 2006), to the Russian Far East ( Sundukov 2017), Japan, northern India ( Smith 1975), reaching into the Oriental Region in China (see Specimens examined), and transcontinental in North America ( Smith 1975). According to Ross (1932), Hemichroa crocea was probably introduced to North America, but Kriegl (1964) concluded that the species occurs there naturally, because a similar assemblage of parasitoid species is found in Europe and North America.

Occurrence in Sweden.

Published records: Skåne ( Andersson 1962), "sparingly, but distributed from Skåne to Lapland" ( Thomson 1871). Material was examined from Skåne, Småland, Öland, Gotska Sandön, Södermanland, Dalarna, Lappmark.

Specimens examined.

Canada: Quebec: 1♀ (DEI-GISHym15340), Gatineau Park 1.8km N Eardley, Juniperus virginiana stand, 60-80 m, 45.56667N, 76.09139W, 31.08.-07.09.2012, leg. CNC Hymenoptera Team (SDEI). China: Sichuan: 1♀ (DEI-GISHym17831), Gongga Shan, 2200 m, 29.59700N, 102.05000E, 29.06.2009, leg. Blank, Liston & Taeger (SDEI). Germany: Baden-Württemberg: 1♀ (SDEI). Bayern: 4♀ (BC ZSM HYM 04090, 04091, 16633, 16740) (ZSM). Berlin: 1♀ (SDEI). Brandenburg: 1♀ (DEI-GISHym19401) (SDEI). Hessen: 1♀ (DEI-GISHym17970) (SDEI). Mecklenburg-Vorpommern: 1♀ (DEI-GISHym19402) (SDEI). 1♂ (DEI-GISHym31838), Kalkhorst near Neustrelitz, 53.31666N, 13.06666E, 27.06.1884, leg. F. W. Konow (SDEI). Nordrhein-Westfalen: 1♀ (SDEI). Sachsen: 1♀ (SDEI). Portugal: Viana do Castelo: 1♀ (DEI-GISHym19668), Monção 10 km E, 30 m, 42.08658N, 8.36285W, 09.05.2012, leg. Blank, Jacobs, Liston & Taeger (SDEI). Sweden: Skåne: 1♀ (NHRS-HEVA000006485), leg. Boheman (NHRS). Småland: 1♀ (NHRS-HEVA000006489), Kalmar, 05.1919, leg. Hedgren (NHRS). Öland: 1♀ (NHRS-HEVA000003424), Stora Rör, 08.08.1941, leg. Wieslander (NHRS). Gotska Sandön: 1♀ (NHRS-HEVA000006487), leg. Jansson (NHRS). Södermanland: 1♀ (NHRS-HEVA000006488), Drevviken, leg. Smidt (NHRS). Dalarna: 1♀ (NHRS-HEVA000006486), "Dalecarlia alpina ", leg. Boheman (NHRS). Middle and southern Lapland: 1♀ (NHRS-HEVA000006491), "Lapponia meridionalis", leg. Boheman (NHRS). 1♀ (NHRS-HEVA000006492), "Lapponia intermedia", leg. unknown (NHRS).

Figures

Figures 98 - 103. Hemichroa 98 - 100 crocea DEI-GISHym 19402 ♀, Germany, Mecklenburg-Vorpommern 99, 101 australis DEI-GISHym 15401 ♀, Sweden, Torne Lappmark 102 crocea DEI-GISHym 31838 ♂, Germany, Mecklenburg-Vorpommern 103 australis DEI-GISHym 20618 ♂, Sweden, Torne Lappmark, fore wing. Scale bar: 2 mm.

Figures 108 - 112. Hemichroa, lancets 108 - 109 australis DEI-GISHym 15387, Sweden, Torne Lappmark; arrow, spurette 110 australis DEI-GISHym 31836, Ukraine, Carpathians 111 australis DEI-GISHym 31837, Russian Federation, Baskiria 112 crocea DEI-GISHym 19401, Germany, Brandenburg; arrow, spurette.

Figures 104 - 107. Hemichroa, penis valves 104 australis DEI-GISHym 15392 Germany, Saxony 105 australis DEI-GISHym 20618, Sweden, Kiruna 106 australis DEI-GISHym 84982, Japan, Honshu 107 crocea DEI-GISHym 31838, Germany, Mecklenburg-Vorpommern.

Figures 77 - 87. Larvae of Nematinae 77 Cladius grandis 78 Euura sp. amentorum group 79 Nematinus acuminatus 80 Nematinus luteus 81 Nematinus steini 82 - 83 Anoplonyx albitarsis 84 Hoplocampa crataegi 85 Stauronematus platycerus 86 Pristiphora malaisei from Potentilla fruticosa 87 Hemichroa crocea.