Gelis declivis (Foerster, 1850)

Verheyde, Fons, Jacobs, JEffrEY, Dekoninck, WOUTEr, Achterberg, Kees Van, Rond, JErOEn, Blanck, Tim De, Schoonvaere, KarEL, Nieuwenhuijsen, Hans, Ketelaere, Augustijn De, Minnebo, BarT & Ferrer-Suay, Mar, 2023, Remarks on Hymenoptera on urban green roofs in Belgium, Belgian Journal of Entomology 140, pp. 1-37 : 27

Gelis declivis (Foerster, 1850) - Belg. sp. nov.

BELGIUM: • 1 ♀; N51.193° E4.417°; v/2021; J. Jacobs leg.; coll. FV; pitfall trap; I. Österblad det. • 1 ♀; N51.135° E4.241°; v/2021; J. Jacobs leg.; coll. FV; pitfall trap; I. Österblad det. • 1 ♀; N51.193° E4.417°; vi/2021; J. Jacobs leg.; coll. FV; pitfall trap; I. Österblad det. • 1 ♀; N51.125° E4.260°; viii/2021; J. Jacobs leg.; coll. FV; pitfall trap; I. Österblad det. • 3 ♀♀; N51.135° E4.241°; ix/2021; J. Jacobs leg.; coll. FV; pitfall trap; I. Österblad det. [5 occ. (1 year), 3 roofs]

Remarks:

Gelis spp. are difficult to identify, therefore the specimens were send to Ika Österblad, who carefully identified these using her experience and existing keys like SCHWARZ, 2002. Both G. declivis and the species below, G. festinans , are darker and small species. Females are apterous. Both species can be placed in the group of species with a distinct and deep furrow at the malar space, with the genal carina nearly always joining oral carina at mandibular base. Further identification is mostly based on a combination of characters. A distinct character within the so called G. festinans -complex are the meso- and metapleuron, which are completely connected to each other in G. declivis . The host is unknown, but is probably similar to G. festinans (see Discussion).