Xorides alpestris (Habermehl, 1903)

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 : 128-129

Xorides alpestris (Habermehl, 1903)

Xorides spp. are parasitoids of wood-boring insects. They have a clear habitus, often robust, and females with white-banded antennae. They can be distinguished from other families by some of the following characteristics: fore wing with vein 3r-m absent, tarsal claws simple, first tergite without glymmae, fore wing vein 2m-cu with two bullae, propodeum with at least a trace of the anterior transverse carina, etc. (more details see GAULD & FITTON, 1981).

Xorides alpestris is a huge species (at least 15 mm) which can be distinguished from other species by the face and the frons (entirely black), its long and narrow pterostigma (four times as long as wide), the hind coxae which are polished and the hind tibiae which are white basally (CLÉMENT, 1938; VARGA, 2014). Additionally, we noticed the basal flagellomeres of many specimens are often orange (in addition to the normal white ring on the otherwise black antennae). X. alpestris has only been recently observed in the Low Countries, which is probably due to the increasing amount of dead wood in nature reserves and gardens and areal expansion of (Central- and Eastern-) European ichneumonids ( VERHEYDE et al., 2020a). Animals are often found on (standing) wounded or dead wood, for example beeches or birches next to heathlands or on forest borders. First report for Belgium and the Netherlands.

MATERIAL EXAMINED:

BELGIUM: • 1 ♀; Malderen, Marselaerbossen (VB); 51°02’14”N 4°16’19”E; 15/viii/2015; J. Reyniers leg.; field observation; C. Thirion & F. Verheyde det. (ObsID: 105516412) . • 1 ♀; Nazareth, Hospicebossen (OVL); 50°58’46”N 3°37’20”E; 24/vii/2018; J. Raes leg.; field observation; F. Verheyde det. (ObsID: 160427330) . • 1 ♀; Brussel, Begijnenbosdal (BR); 50°54’19”N 4°23’44”E; 24/vii/2018; F. Dierge leg.; field observation; F. Verheyde det. (ObsID: 160451607) . • 1 ♂; Beernem, Bulskampveld - Heideveld-Bornebeek (WVL); 51°07’07”N 3°17’24”E; 17/v/2020; A. De Ketelaere leg.; coll. ADK; field observation on Fagus sylvatica ; G. Várkonyi, A. De Ketelaere & F. Verheyde det. (ObsID: 191750278) . • 1 ♂; Zillebeke, Zandvoordebos (WVL); 50°49’25”N 2°57’55”E; 23/v/2020; F. Verheyde leg.; coll. FV; field observation on Fagus sylvatica ; A. De Ketelaere & F. Verheyde det. (ObsID: 192192921) […] .

THE NETHERLANDS: • 1 ♀; Ravenswoud , Compagnonsbosschen (FR); 52°58’21”N 6°22’54”E; 26/vi/2012; A. van Hengstum leg.; field observation; F. Verheyde det. (ObsID: 69410543) . • 1 ♀; Hilversum (NH); 52°13’40”N 5°12’08”E; 26/ix/2013; T. van Wijk leg.; field observation; O. Varga & F. Verheyde det. (ObsID: 79310064) . • 1 ♀; Emmen , Bargerveen (DR); 52°41’59”N 7°01’28”E; 5/viii/2017; S. Wiebing leg.; field observation; F. Verheyde det. (ObsID: 142451644) . • 1 ♀; Vaals , Schimperbos (LIN); 50°45’16”N 5°59’27”E; 29/vi/2019; S. Lamberts leg.; field observation; F. Verheyde det. (ObsID: 175407282) . • 21 ♂♂; Eindhoven , Stratumse heide (NB); 51°24’27”N 5°30’15”E; 22/v/2020; R. Aussems leg.; field observation; F. Verheyde det. (ObsID: 192847169) […] .