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Buff-tailed bumblebee observed removing a larva from the nest

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Hello all

a user of BeeWatch recently uploaded an interesting photo showing an adult buff-tailed removing a larva from the nest. I had not seen this behaviour for myself so I am really interested to learn more.
A quick search on the internet revealed that bumblebees can removed wax-moth larvae and dead bumblebees.
My first thoughts were that is it a pest such as the wax-moth? But having seen some pics on the web, I thought that the larva in the photo looks more like a bumblebee larva, because it’s more chunky.

I couldn’t upload the photo with this post as the file size was too large. So I uploaded it to iSPOT. Here is the link. The post is called ‘Bterrestris removing larva’

http://www.ispot.org.uk/node/287986?nav=latest_observations

I would really appreciate it if you could follow the link. Can anyone identify the larva and does anyone know anymore about this type of behaviour in bumblebees?

Yours appreciatively, elaine

PS following Clive’s guidance I have finally managed to attach a cropped version of the photo here!

     

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Hi Elaine,

The other day, I tried to send you some feedback about this really interesting and useful photo:  but somehow I messed up sending it and it just vanished !

Then I rang BBCT and talked over my comments with you, promising to have a go at a re-send, as well to email you some related photos showing that BB larvae are moved in the nest sometimes. 
(Maybe we can assemble these in a different post !)

So, here goes ......
I think this is a bumblebee larva: and quite a large one - so maybe on the verge of pupating.

Honey bee colonies regularly toss debris out of their hive entrance and, if the weather is good, fly off a short distance an dump it.  In the spring you find bits of dead pupae at the entrance, when cold weather has caused the brood nest to contract away and peripheral brood gets chilled and dies.  (Around this time of year [August] the colonies scrap the drones, and you can get little dumps of drone corpses near to a hive.)

So, I think the photo just shows a bumblebee which is on Nest Hygiene duties.

Over the years I have moved a good number of BB nests and have fairly often found larvae discarded not far from the entrance, or in a latrine area inside their re-homing box.  And dead bees appear there too. 

A larva was discarded below a B. hypnorum colony I had moved to the garden this year - but unfortunately I can’t find a photo of it - although I do have the larva !

I have managed to locate some photos which show larvae discarded in the latrine area of a bumblebee box: and also a natural latrine area of a B. hypnorum colony that was established in the vent system of a Tumble Drier - as proof that bumblebees do naturally set up latrine areas close to their nests.

You ask if this creature being ejected in the photo could be an Aphomia sociella caterpillar: but I don’t think it is, because to my eyes it is not the right shape; and it doesn’t have the brown head and mouthparts of an A. sociella caterpillar.

I’ve now looked out some relevant photos, and will attempt to attach them here, of to further replies to this Post.

Yours             Clive

     

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Here is photo showing Bumblebee Waxmoth (A. sociella) caterpillars.
They are always in groups, and hide beneath tough silk.  They are highly mobile.

Clive

     

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Now here is a photo of the Latrine area of a B. hypnorum colony which had been established in a fluff-filled (unused) side-arm of a Tumble Drier.
The latrine was at the far end of the tube, just behind a blank-off plate, which we removed to assess where the bee nest was !
Note the apparent moistness of the accumulated faeces, and the bump, which may well be a dumped larva.
Clive

     

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Clive

thank you so much for all of this fascinating information.
The photo of the wax moth caterpillars is really useful too.
There can be no doubt now that the larva in question is a bumblebee one and not a pest of some sort.

And now I know why they need a separate latrine area!

regards, elaine

     
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Hi Elaine,

Thanks for your comments.

The latrine areas in those two photos was very damp - or rather wet.  A strong colony produces quite a significant amount of faeces, which are obviously very fluid, but with a major content of pollen residues.  The mix smells strongly ammoniacal too- a bit like a horse-manure heap !

If you use Cat Litter absorbent(as recommended by Kearns & Thomson) in the vestibule of a BB box you can control it, but may have to change the cat litter if it gets too soggy - as in the photo.  In natural nest places the surrounding earth, or air movement will probably allow the fluid to drain away, or evaporate- but not in the recesses of a Tumbler Drier.

In my experience Wax Moth is a dreadful challenge to bumblebee colonies and nearly all the colonies I’ve seen have had it at the time of collection, or get it later.  Prof Dave Goulson is firmly of the opinion that it is a bigger threat in colonies in urban areas than those in the countryside - but nearly all the BB colonies you get asked to move are in an urban environment.

The silk that the moth community produce when they prepare to over-winter is astonishingly strong and dense - almost like a piece of polyurethane furniture foam in its’s resilience , but it has a tubular structure, with a tube for each caterpillar.

How about accumulating these comments about Wax Moth, Latrines, Nest box techniques each in their separate Forum Theads, so that the info is more readily accessible ?? !

Yours         Clive

     
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Hi Clive and Elaine,

I have read this post and thought you may find this interesting…... http://bit.ly/RXh8zW

it is apart of another video I made which you may also find interesting….. http://bit.ly/SO37Zn

re wax moths go to….... http://bit.ly/T4uFHR

HTH,

Cheers George