Production of mud by Ancistrocerus wasp

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Ed Phillips
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Joined: 13/05/2012 - 08:41
Production of mud by Ancistrocerus wasp
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Watching Ancistrocerus wasps nest-making in my garden bee-hotel over recent years, I had assumed that they collected mud from damp areas (in a similar way to Osmia bicornis). Last year, I was able to follow a wasp from the bee-hotel to its "collecting point" and saw that it was collecting dry soil particles. This year I witnessed the same thing, with an Ancistrocerus wasp repeatedly returning to the same point. I was able to get a series of photographs from one visit showing her collecting individual soil granules (the soil was bone dry) and then flying off with a wet mud-ball. It would appear that the dry soil granules are mixed with saliva (or whatever the hymenopteran equivalent is!) to create the mud-ball.

 

Checking various bits of literature, I notice that although use of mud is mentioned, how the mud is produced is not. I wondered whether other observers have witnessed this.

 

Ed ...

Nigel Jones
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Reply from Jeremy Early

Three of the six Eumenidae I have seen in gathering mode moistened bone-dry sand. They were Ancistrocerus gazella (in my garden last week), Symmorphus bifasciatus and Symmorphus gracilis. Conceivably this is the usual practice, at least for stem- or wood-nesting species requiring closure of cells and the nest. However, the only time I have seen Ancistrocerus nigricornis collecting soil, in the garden in 2005, the wasp used damp sand rather than dry which was also available. For species that build structures, damp soil makes more sense than dry and this is the uniform method for Eumenes coarctatus creating its ‘pot’.  Odynerus spinipes is another builder, at least as regards the ‘chimney’, and the only time I have seen one collecting soil she used damp sand. Interestingly the one genuine builder among the British pompilids, Auplopus carbonarius, also used damp sand in 2005 and again in 2012. There are many gaps in our knowledge so additional reports of the activity would be useful.

Posted on behalf of Jeremy Early
Ancistrocerus gazella about to head back to nest with soil August 2016 JEREMY EARLY

Ancistrocerus gazella gathering soil in bone dry sand August 2016 JEREMY EARLY

Symmorphus gracilis female with ball of mud 2008 JEREMY EARLY

 

Ed Phillips
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Last seen: 1 year 11 months ago
Joined: 13/05/2012 - 08:41
Thanks ...

Thanks so much for the excellent and informative reply Jeremy (and thanks Nigel for your assistance). I'll continue with my observations!

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