Ancistrocerus nigricornis (Potter Wasp sp.)

Description:

There are 12 different Ancistrocerus species in The Netherlands of which 6 are quite rare.
The other 6 are very difficult (if not impossible) to tell apart from a photo.
However, Ancistrocerus nigricornis can be distinguished by the little "dent" (or hook) at the underside of the abdomen (sternite 2) which is best seen from the side (3rd photo).
In addition, other similar looking potter wasps usually do not fly as early as in April/May but later in the year.

Potter wasps are solitary and feed on flower nectar.
Potter wasps make mud nests for their eggs and larvae or use abandoned burrows of other insects. 
They stock the nests with caterpillars and other grubs, which they seal in with mud. 
These are eaten alive by the wasp larvae.
Potter wasps have the potential to deliver painful stings, but are not aggressive and rarely attack humans.

In my yard, Hilversum, The Netherlands, 10 May 2020

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