Remarks on Hymenoptera on urban green roofs in Belgium Author Verheyde, Fons Author Jacobs, JEffrEY Author Dekoninck, WOUTEr Author Achterberg, Kees Van Author Rond, JErOEn Author Blanck, Tim De Author Schoonvaere, KarEL Author Nieuwenhuijsen, Hans Author Ketelaere, Augustijn De Author Minnebo, BarT Author Ferrer-Suay, Mar text Belgian Journal of Entomology 2023 2023-03-03 140 1 37 journal article 10.5281/zenodo.10981934 2295-0214 10981934 EB983FDD-CAE9-48F7-AA63-5F49CC9B6CD1 Lasius umbratus (Nylander, 1846) BELGIUM : • 1 dealate gyne; N51.197° E4.463° ; v/2020 ; J. Jacobs leg.; coll. RBINS ; pitfall trap ; W. Dekoninck det. • 1 dealate gyne; N51.169° E4.394° ; vi/2020 ; J. Jacobs leg.; coll. RBINS ; pitfall trap ; W. Dekoninck det. • 1 dealate gyne; N51.205° E4.399° ; viii/2020 ; J. Jacobs leg.; coll. RBINS ; pitfall trap ; W. Dekoninck det. • 1 dealate gyne; N51.125° E4.260° ; ix/2020 ; J. Jacobs leg.; coll. RBINS ; pitfall trap ; W. Dekoninck det. • 1 dealate gyne; N51.199° E4.459° ; viii/2021 ; J. Jacobs leg.; coll. RBINS ; pitfall trap ; W. Dekoninck det. • 1 dealate gyne; N51.135° E4.241° ; viii/2021 ; J. Jacobs leg.; coll. RBINS ; pitfall trap ; W. Dekoninck det. [6 occ. (2 years), 6 roofs] Remarks: Only dealate gynes of this species were found and not a single worker. These gynes are probaly collected shortly after their nuptial flight when foraging to find a Lasius s. str. nest to parasitize (temporary), most likely Lasius niger . The lack of workers during this sampling campaign indicates that settlement by L . umbratus was so far not successful on the sampled green roofs. Probably this species and other Chthonolasius spp. have no options to settle on these roofs. After the temporary parasitic phase they normally prefer to make nests that are situated deep in the ground where they tend aphids on roots of grasses and/or herbs with rosettes.