This female Gasteruption assectator agg.  hung arond the gardenhose…
…shortly after she left a male appeared and was clearly inspecting the same spot for her scent.
While he was sniffing around she re-appeared and inspected him.
Eventually they flew off towards the ground and disappeared from sight, possibly retreating into the plants but I couldn’t trace them.
References1 Johansson N, Achterberg C van (2016) Revision of the Palaearctic Gasteruption assectator aggregate, with special reference to Sweden (Hymenoptera, Gasteruptiidae). ZooKeys 615: 73-94. https://doi.org/10.3897/zookeys.615.8857