Exeristes roborator (Fabricius, 1793)

Verheyde, Fons, Hoekstra, Paul, Libert, Pierre-Nicolas, Meijer, Hilco, Ketelaere, Augustijn De, Vandaudenard, Thibaud, Belgers, Dick & Brosens, Edwin, 1880, Two hundred and five ichneumonid wasps reported for the first time in Belgium and the Netherlands (Hymenoptera: Ichneumonidae), Belgian Journal of Entomology 122, pp. 1-142 : 105-106

Exeristes roborator (Fabricius, 1793) (Fig. 54 A–B)

Exeristes spp. closely resemble Scambus spp. on habitus. In contrast to the latter genus however, the occipital carina is mediodorsally dipped (FITTON et al., 1988).

Furthermore, some characteristics in E. roborator are unusual and make it ‘unkeyable’ for Scambus : front and middle coxae black but hind coxae red, a rather high ovipositor-hind tibia index (at least 2) and orange colouration of apical flagellomeres (Fig. 54 A). Additionally, to distinguish it from other species in the genus, the females have a little tubercle on the dorsal valve (Fig. 54 B); the males have a medial tooth on their clypeus ( KASPARYAN, 1981a). Much like Scambus spp. , E. roborator is probably a common parasitoid wasp with a wide range of hosts (see YU et al., 2012) often linked to flower heads and is primarily active from the summer onwards. First report for the Netherlands; confirmed in Belgium.

MATERIAL EXAMINED:

BELGIUM: • 1 ♀; Roosbeek (VB); 50°50’04”N 4°51’34”E; 14/vi/2019; J. Coppens leg.; field observation; O. Varga det. (ObsID: 174462344) . • 1 ♀; Merksem (AN); 51°14’22”N 4°27’10”E; 1/vii/2020; S. Verheyen leg.; field observation on Daucus carota ; F. Verheyde & O. Varga det. (ObsID: 174462344) . • 1 ♀; Zonnebeke , Haneveld (WVL); 50°52’17”N 2°57’52”E; 19/vii/2020; F. Verheyde leg.; coll. FV; field observation on Cirsium arvense ; F. Verheyde det. (ObsID: 196577154); Fig. 54 A–B .

THE NETHERLANDS: • 1 ♀; Budel-Dorplein (NB); 51°13’46”N 5°36’30”E; 9/viii/2013; J. Bouwmans leg.; field observation; F. Verheyde & O. Varga det. (ObsID: 78369419) . • 1 ♀; Vlaardingen , Volksbos (ZH); 51°54’09”N 4°17’36”E; 22/vii/2016; E. Kester leg.; field observation; F. Verheyde det. (ObsID: 121884476) . • 1 ♀; Losser (OR); 52°17’49”N 6°58’34”E; 2/vii/2018; M. Bonte leg.; field observation; F. Verheyde & O. Varga det. (ObsID: 159541493) .