What's That Bug? does not endorse extermination

Probable spider coccoon in Romania
Location: Brasov, Transylvania, Romania
November 29, 2011 3:42 am
Greetings from Romania. I recently tidied up my study and found 5 cocoons underneath a cloth. They had been laid on a picture frame which had been underneath the cloth (actually a cloth bag for an Australian Barmah hat). They measure 1 inch long and less than half inch wide (2.5 cms by 1.2cms). They are clay coloured and are hard to the touch just like baked clay.I opened one and found 8 dried dead spiders inside. They each have 8 hairy legs under the magnifying glass. I have attached a photo. Have you any idea what they are?
Signature: Dr Haydn Deane

Mud Nest

Dear Dr. Deane,
Spiders do not form a cocoon and insects that form a cocoon create a solitary cocoon.  What you describe sounds like a Wasp’s Nest.  There are many wasps that build a mud nest that is provisioned with insects or spiders for a developing larva, generally a single larva per cell.  The structures in your photograph do not resemble any mud Wasp Nests that we are familiar with, but spiders tend to be a common prey for wasps that build a mud nest.  The other puzzle is why that picture frame was chosen as the location.  For now, this will be posted as a Mystery on our site.

possibly a Wasp Nest

Dear Daniel,  Thanks for the prompt reply. You are completely right. I opened another of the nests and inside was the creamy coloured grub in it’s red- brown thin sleeve. The grub is soft but does not move. Pictures enclosed
However I am very puzzled as these mud wasps are not known in Romania. They have been discovered in the Czech Republic and Italy. We live in Brasov, Transylvania in the mountains at an elevation of 600mtres. The cloth that was covering the site of the nests was from an Australian hat. Could it be that the wasp was inside the lining of the cloth bag and travelled all the way to Romania from Australia, then deciding to lay it’s eggs on my photo album lying underneath the bag? Seems a bit far fetched! And it flew in through the window of my study on goodness knows how many occasions with the mud!!
I have done a bit of my own research and it matches the black and yellow mud spider nest, see
http://wiki.bugwood.org/HPIPM:Black_and_Yellow_Mud_Dauber
I did see a very strange looking wasp in our garden matching the description of the Black and Yellow Mud Dauber this autumn. I have never seen another.
Best regards
Dr Haydn J H Deane MB BCh BAO

Hi again Dr. Deane,
Though the species of wasp you found might not be found in Romania, we feel quite certain that there must be some local species.  Since Mud Wasps are somewhat particular about their host prey, we don’t think it likely that an Australian wasp managed to provision five nest chambers in a foreign land.  We did not receive the grub photo and we would love for you to resend it.

Daniel, Apologies, Here are 3 almost the same but may be of interest to you. I do have a small stream outside my study window so that is presumably where the mud was collected
Many thanks for your help
Best regards
Haydn

Mud Wasp Larva

Thanks Haydn,
We would urge you to allow the remaining cells to mature and metamorphose into adults that can easily gain access to the outdoors come spring.

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What's That Bug? does not endorse extermination
Location: Romania

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