Bee hotel:
Wasp nest!
Ectemnius cavifrons ♀︎
-Eupeodes latifasciatus-

Last update: 30 September 2021
OBSERVATION:
2021-IX-07

This Ectemnius female carrying a prey slipped into a nest hole on bee hotel block 3 in section III. Normally the females of this genus do not nest on bee hotels but the wood of this particular block is deteriorating under the continuous weather onslaught and became soft. She uses the drill hole as a foundation to tunnel further into the wood, which can be concluded from the rather large mount of wood dust collecting on the nest block below.
Earlier Ectemnius females entering a nest hole carrying prey, see here, remained anonymous but this time it turns out to be Ectemnius cavifrons [1].

This female was already actively building another nest for some days, see Fig 1. The lower location belongs to the observation in this article. A nice observation.

Ectemnius cavifrons ♀, nestlokaties

During the period the wasp has been observed two of the four prey items she brought to the nest were somewhat clear on the photographs. It is a hover fly. Based on a number of characters (see also below) and the observation date this seems to be Eupeodes latifasciatus, a species known from her preyspectrum.

Here she arrives with specimen 1…

Ectemnius cavifrons ♀︎ with Eupeodes latifasciatus
Ectemnius cavifrons ♀︎ with Eupeodes latifasciatus

…and here with specimen 2.

Ectemnius cavifrons ♀︎ with Eupeodes latifasciatus
Ectemnius cavifrons ♀︎ with Eupeodes latifasciatus

The hover fly characters leading to E. Latifasciatus:

1. Abdominal bands do not continue to side (photo 1,2,4)

2. Sternites 3 and 4 with black spot (foto 1) (character: always sternite 2, sometimes 3 and 4)
    Based on this example the spot on sternite 2 can be very small and not visible in the photo:   
https://www.discoverlife.org/mp/20p?see=I_MWS139132&res=640
https://www.discoverlife.org/mp/20p?see=I_MWS139137&res=640

   E. nitidicollis has different scheme ventrally based on this example:
https://www.researchgate.net/figure/Epistrophe-nitidicollis-male-A-Adult-B-Wing-C-Ventral-view-of-abdomen-D-Dorsal_fig1_260501253

3. Yellow band behind eye consistently wide (photo 1,4)

4. The apical edge of the band on tergite 4 is light-yellow and contrastst with the orange of the rest of the band (not a character kenmerk, visible on Eupeodes not on Epistrophe)


References

1 Nederlands Soortenregister

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