I found this tube and wondered which animal built it.

It is 2 cm long and has an entrance/exit hole on one side. The material seems to be sandy.

I assume it is for breeding purposes.

Before finding the tube, I saw an unfamiliar kind of wasp around (could also be a hornet), with very long black legs. However, I could not find a wasp or hornet that builds such tubes, so it could be unrelated.

Location is Germany.

My questions are: which organism built this structure and should I expect anything crawling out one day? Or is it unfinished, since the entrance isn't closed?

Tube from above

Tube entrance


1 Answer 1


This is the nest of a Mud dauber, also known as Mud wasp. This was possibly made by a Black and Yellow Mud dauber based on the following information.

The nest of the black and yellow mud dauber is a simple, one-cell, urn-shaped nest. 1*

As for expecting something coming out of it? I doubt it, as the nests are sealed after depositing an egg.

After building a cell of the nest, the female wasp captures several spiders. The captured prey are stung and paralyzed before being placed in the nest (usually 6-15 per cell), and then a single egg is deposited on the prey within each cell. The wasp then seals the cell with a thick mud plug. 2*

Eventually, the hatching larva will eat the prey and emerge from the nest.

  • 3
    $\begingroup$ You are right. Just saw mommy coming back to continue her work :) Interestingly, they were introduced in Germany in the 70s/80s. $\endgroup$
    – Arsak
    Jul 16, 2017 at 10:18
  • 3
    $\begingroup$ @another'Homosapien' Quoting sources [1][2]: "Not normally aggressive, but can become belligerent when threatened." & "Stings are rare due to their usually peaceful nature, however nests are aggressively defended." $\endgroup$ Jul 16, 2017 at 17:33
  • 4
    $\begingroup$ This wasp is thought to be responsible for the deaths of over 180 people when an airliner crashed after the wasp built it's nest in a tube - en.wikipedia.org/wiki/Birgenair_Flight_301 $\endgroup$
    – Tim
    Jul 16, 2017 at 22:23

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