Ischnus alternator (Gravenhorst, 1829)

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 : 60

Ischnus alternator (Gravenhorst, 1829)

Somewhat more common than the preceding species is I. alternator . It is easy to recognise by the basis of several white rings on the hind legs (tibiae basally, tarsi) and white tibial spurs. Sometimes the antennae are orange basally. Lastly, the first tergite of the metasoma basally has a distinct tooth laterally (SCHWARZ [2013], draft key). Our findings demonstrate it is very common in traps on open and more sandy grounds, presumably searching its hosts ( Tortricidae ).

First report for Belgium; confirmed in the Netherlands.

MATERIAL EXAMINED:

BELGIUM: • 1 ♀; Antwerpen , Hobokense Polder (AN); 51°11’16”N 4°20’60”E; 7/vii/2007; L. Janssen leg.; field observation; C. Thirion det. (ObsID: 52365386) . • 1 ♀; Schoten , Orangerie De Vlinder (AN); 51°15’28”N 4°29’24”E; 15/ix/2011; L. Janssen leg.; field observation; F. Verheyde det. (ObsID: 61194635) . • 1 ♂; Tienen (VB); 50°48’32”N 4°56’44”E; 22/ix/2011; G. Wynants leg.; field observation; C. Thirion det. (ObsID: 61181939) . • 1 ♀; Erpe-Mere (OVL); 50°56’37”N 3°58’17”E; 7/vii/2012; G. Van Heghe leg.; field observation; F. Verheyde det. (ObsID: 146483854) . • 10 ♀♀ 1 ♂; Sint-Andries , Beisbroek , Chartreuzinnenheide , Heide Zevenkerken & Ter Heyde (WVL); VIII.2015 – X.2016; W. Dekoninck et al. (KBIN) leg.; coll. KBIN/RBINS (project Bruges heathlands); yellow pan trap & pitfall trap; F. Verheyde det. […].

THE NETHERLANDS: • 1 ♀; Eijsden (LIN); 50°47’33”N 5°41’47”E; 6/ix/2012; J. Wiersma leg.; field observation; F. Verheyde det. (ObsID: 71016314) . • 1 ♂; Ameland (FR); 53°26’29”N 5°42’56”E; 13/vii/2013; T. Kiewiet leg.; field observation; F. Verheyde det. (ObsID: 77549145) . • 1 ♀; Rotterdam, Blijdorp (ZH); 51°55’51”N 4°26’55”E; 24/viii/2013; J. de Gans leg.; field observation; F. Verheyde det. (ObsID: 78650781) . • 1 ♀; Bennekom (GE); 51°59’59”N 5°40’09”E; 1/ix/2013; M. de Jonge leg.; field observation; F. Verheyde det. (ObsID: 78860897) . • 1 ♀; Utrecht, Leidsche Rijn (UT); 52°05’30”N 5°02’30”E; 29/viii/2014; M. Braad leg.; field observation; F. Verheyde det. (ObsID: 87553960) […] .