Bee larvae turning into cocoons
Have spent some days off, back in the countryside, I have been try to follow their development after the 6 week period of adult life. The tubes as ever allow me into their otherwise hidden private world.
The bee larvae are no longer clearly visible, and more cocoons are in place. It is interesting that being of freshly spun silk that they appear not white, but golden brown (and moist) at this initial stage of metamorphosis.
Here is the first photo of the tubes to the left side of the box (annotated for interest):
My notes:
- In the photo of this outer cell, the pollen stock and larva is apparently gone without a trace. However on closer examination with more light, it looks like a tiny golden brown blob (a cocoon?) appears lodged between the wall line of the first and second cells, and similarly one between the second and third partition. Could then the moistness of the new cocoons allow the expansion of the bee as it goes through its transformation? My initial impressions of other cocoon sizes made me think that they were males. However the cocoon starting size is very probably a function of the larva size from its available pollen stock before it starts spinning its cocoon.
- There is an extremely large stock of nectar/honey in this back cell of three. The reflecting flash of the photo seems to have missed capturing the off-white lava that appears to still be feeding. Bearing in mind that there are several stages of larvae present, I suppose I can assume that logically, the larva will only start the metamorphic cocoon stage when all food is gone.
- This tube, four levels down, is a bit of a mystery. It looks like pollen is smeared all round the surface. [Perhaps the female bee had a bad dose of hay-fever that day before sealing the hole!?] Perhaps the stock of pollen is so great the larva has yet to munch through it. I will try and write an update.
- A newly spun cocoon.
- Newly cocoon – its near mature adult bee size is what led me to initially think that n°1 had disappeared.
- As of today (25 June) the two cells either side of n°6 have their larvae visible, see as the white parts in the tube.
- This may be a humidity issue creating a furry mould on the pollen. Several cells were seen last year when the summer was constantly wet, however to the left side there appears to be the edge of a cocoon. Like those cocoons last summer, this may not be the end of the solitary bee larva. The suspected mould may not be damaging to the young bee, nor may it necessarily degrade the cocoon.
- This is the real curiosity. I will have to check my photos, but I remember that as one of the last cells to be created, it pretty soon seemed to fill up with at least ten thinner and longer squirming larvae. However even more curiously, a week later only one very large and very ‘real-time’ wiggly larva (maybe light-sensitive) remained. Had it cannibalised its siblings? Whatever this mini-monster is, it has already gone into the cocoon phase. Perhaps it is a parasitic wasp that has fed off the work of the last bees, perhaps it was some mites which appeared hovered mainly around the paper tubes. I hope that in fact it is one of the other bee species that appeared late in the day. Update: Will post soon with pictures taken of the monstrous developments.
All these observations are possible because of my choice of clear see-through PVC tubes. Although it is environmentally unfriendly and doesn’t happily bio-degrade, they can be re-used. So I think it is serving a positive purpose here.
As I have had a bit of time today, I made one last photo of the artificial bee habitats that I am using. Or should I say, will use. The commercially bought plastic honey-comb blocks when delivered were off-gassing considerably. I placed one next to my main block when the bees were active, but none were occupied. So they will be left to winter outside – hopefully to be ready for next season.
Tags: humidity, off-gassing
January 9th, 2009 at 7:44 pm
[...] Ich bin noch auf folgende Seite durch ein Kommentar auf meinem Photoblog gestoßen: solitarybee.com (English) auf der es ganz interessatne Informationen und Bilder zu den Nistplätzen von [...]
August 22nd, 2009 at 1:06 pm
If you dont mind me asking where did you get those plastic honeycomb things from? I made a few nests this year out of wood but they say you cant use them for more than a few years so I am looking for something reusable. A honeycomb block like that looks really handy. As long as the bees dont mind the plastic.
August 24th, 2009 at 11:55 pm
Hi Duncan,
Happy to share my sources – I found these @ http://www.masonbeehomes.com. (tell them who recommended them, thanks)
…and they are not bad, but there’s quite a bit of off-gassing (a strong smell of plastic) from the two-block one house set I bought in 2008, and I don’t know whether this is off-putting for the bees. It was only this year that I had one bee creating three cocoons, and this was after I left the honeycombs exposed to to the wind all the winter. To be fair the block wasn’t in the brick wall area where most of my bees are active.
If you buy two, you can rotate the blocks, but you won’t be able to retrieve or disinfect the cocoons if mites or other fly parasites such as Cacoxenus indagator move in, but I guess you can clean out the honeycombs.
It really depends if you are wanting to harvest the cocoons, or just leave them alone. If you fancy harvesting cocoons and/or keeping the parasite population down, I would also recommend AndrewsReclaimed at Etsy, and this particular nest block with trays which you can take apart and disinfect: http://www.etsy.com/view_listing.php?listing_id=28132782
Let me know which way you go, and above all I would love to hear about your success/history with solitary bees. Email me – Paul@ this domain. Cheers.
October 5th, 2009 at 5:30 pm
I am curious about your plastic habitats you purchased, as well as some habitats you commonly use. About this statement:
“I placed one [masonbeehome habitat] next to my main block when the bees were active, but none were occupied. So they will be left to winter outside – hopefully to be ready for next season.”
Do the white plastic habitats have closed off ends? Were other habitats more successful? If so, which habitats were preferred, and why do you suppose they were better?
February 2nd, 2010 at 12:44 am
[...] I first saw evidence of mites in my plastic tube bee observation box in June 2008, I didn’t know what had happened. [...]
September 8th, 2010 at 11:12 pm
Sorry about my very late reply Kimball.
In respect of the purchased plastic-based habitats, there was a strong smell of plastic the ‘off-gassing’ from the materials used. This unnatural aroma led me to think that it might put off the bees who normally seek holes in wall or tress, so yes having left the untouched habitats outside over winter (2009/10) has meant that the gases are less strong.
One mason bee did take up the opportunity last year but it’s progeny didn’t return to nest in the habitat. However this is probably due to the fact that (despite it being exposed to the afternoon sun) it was North facing and the bee prefer morning sun. I left it there, because I have begun to realise that to expand my bee population I must be able to to clean out the parasites in the tunnels. If not, the young bees can get blocked by failed cells, get pollen mite infestations, or the Cacoxenus indagator (bee flies – see my post) would start to really infest the habitats (as they did in 2008) and thus put a brake on the bee population expansion. So you do need to be able to disinfect the tunnels without harming the bee cocoons inside (hence my choice of habitats since).
For your other questions: The white plastic insert habitats were designed to be flush with the wood, so they are essentially ‘sealed’. Other habitats were much more successful however, but I put this down to the choice of habitats that they have – wood drill blocks, brown paper tubes and reed/hollow-stem plants (pond reeds, dried hogweed and Japanese Knotweed +). It means that mean the bees (and different species that arrive at different times) can choose to nest and remain where they are most comfortable. My own bee observation boxes (using 10cm cut of narrow plastic hose) have no off-gas problems and are sealed at the back by the wooden dowelling that hold them in place in the hinged roof box.
Thanks for commenting.