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The Tree Bumblebee - B. hypnorum

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Hi Vanessa,

Good photos and definitely B. hypnorum (the Tree Bumblebee).

B. hypnorum fascinates me.  I’m a beekeeper who has become fascinated by bumblebees, which are to me even more fascinating than honey bees - and you don’t have the bother of dealing with a honey crop either !  So I have some significant bee handling skills.

I’ve had one or two colonies of hypnorum in bird boxes in my garden for the last three or four years. Two have set up home there themselves, the rest have been re-located here.  I put them on the apex of the back wall of my garage, so they can be watched easily, but don’t usually get in our way.

I recently re-located a colony to my garden to allow a person with a tiny garden to use that garden again - rather like your situation.

As a result I’ve been able to get some more video footage showing what Drone cloud ‘nest surveillance’ looks like.  This colony is very strong - but others can be quite short-lived.  The drone activity can be incredibly busy and persistent, but it is significantly reduced by colder weather conditions, or rain.

(Ben Darvill of BBCT plans to work up some of this footage to generate some video evidence of B. hypnorum drone clouds for the website. We had some footage of a colony of mine from about three years ago on the Mark1 website, but it needs updating for the new Mk2 version.)

The annual cycle of bumblebees is that colonies are active for two to say eight months, depending on species.  If a colony reaches full strength, it will produce ‘reproductives’.  These queens will then mate and go off somewhere to hibernate over winter.
Although a colony may restart in a similar (close-by) area the following spring, this is most unlikely to be in an old nest.

In my experience most colonies of bumblebees will eventually go down from wax moth attack.  The caterpillars start at the bottom of the nest, fill it up with protective and amazingly strong caterpillar silk, then live beneath this and eat their way upwards.  The bees get demoralised and the colony eventually succumbs.  One sign of wax moth attack is finding the odd bee crawling about which is missing bits.

My experience is that you get about 100 caterpillars.  Eventually they make a strong spongey mass of silk about 10 x 5 x 5 cm, or more, then prepare to pupate in it.  They change to pupae the following spring and emerge as moths around May/June ish.  The moths look like clothes moths, females bigger than males.  You can kill them before they hatch out as moths by putting the silk structure in a domestic freezer for a few days.

It sounds as though you are making the transition from terror to wonder in your mindset, so do enjoy the glimpses of natural history that are unfolding for you to see.

Come back if I can advise more !

Clive

     
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Hi Vanessa,

It’s B Hypnorum, (tree bumblebee) that has only been seen in this country since 2000. It has come over from Europe and seems to be doing very well over here. This bee can be double brooded and the new queens can be seen searching for nest in March and again in June with the new females seen at the end of May & September.

I won’t go over the good advice Clive has already given earlier in this thread; but just to answer your Q on do they die out or hibernate, the answer is that the nest will naturally die out by autum, if it doesn’t get invaded by wax moth and die out sooner.
It is only the newly mated queens that survive and hopefully, if all goes well, next spring they emerge from their winter hibernation and form a new nest and the whole amazing process starts again !

On the BBCT website its self, there is a good explaination on the BB lifecycle…... click on the ‘about bees’ tab at the top of the page, then on the left hand side click ‘Lifecycle’....

Somewhere on this forum clive mentioned about wax moths and the process that takes place if the nest becomes invaded !

Peter

     
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Hi,
We have a nest in the eaves of our house, unsure of what BB they are but we found this one outside on the ground close to the house, I think its a hypnorum can you confirm

How long will the nest live, we plan to have the Soffits and facias renewed but we are happy to wait until the nest has completed its lifecycle, especially with the decline of the BB’s

I have attatched a Photo for ID purposes

Thanks Mary

     

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Hi Bonebox99,

Yes it is a B. hypnorum.
House eaves, soffit boxes and under roof tiles are all well used by this species - but Bird Boxes are probably even commoner !

If you take a look at some of the earlier posts in this thread, you should find some useful information there.

In the past the colonies I’ve had in Bird Boxes have run out of steam in July.  This is in Bucks.

Come back again if you need any further comments !

Clive

     
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Hi, I have come across this site whilst investigating the bees that are nesting in our loft, accessing under the eaves by my bedroom window and have read this thread with interest as the behaviour described sounds very like what we are seeing, we have small bees going back and forth and have noticed larger bees buzzing around the entrance. I was becoming fairly convinced this was our bee, until my husband tried to get a picture and their heads seem a lot darker than the ones pictured here (pictures are very blurred having been taken of bees in flight whilst leaning out of the bedroom window, he will try again later as he is supposed to be working!) I will try and add a pic later in the hope that some wise person can ID for us.

Helen

     
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Is there anybody out there with access to a B. hypnorum colony which has the usual ongoing Drone bee Nest Surveillance ?

Are they seeing Mating Pairs of the bees ?

I’ve seen this twice now for a very short time period: but they have flown off !

What happens and where do they go ? and how far from the nest ?

I’ve found B. lapidarius (red tailed BB) mating pairs before and they have stayed coupled for ages.

Any comments ?

Clive

     
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Hello all and thanks for all this useful information. I’ve also got some bees nesting under the eaves just above my front door - for about a week now - near Milton Keynes. They are furrier than honey bees, and I’ve seen the odd big one. The behaviour sounds similar to your description - a few busily guarding the entrance and not many actually going in or out. Hard to get a photo, but I will try when I get a moment. I looked in the loft (it’s a bungalow) and there is no sign, but then I spotted a strange pale lantern-shaped thing hanging from a rafter some distance away - it may have been there for years - not very obvious - only 10 or 15 cm high. Wonder if that is the wax moth nest you mentioned, and whether I should try to get at it and put it in the freezer. I’m not very agile, and wouldn’t like to pull it off if it is actually the bee nest (sorry to be so ignorant, I don’t know what the nest looks like).

I previously had a wasps nest under those eaves, and it just died out after a couple of years. They used to strip lots of wood off my garden chairs, but not so much that I minded.

This is just above our heads as we go in and out - that’s me and my brown woolly dog , who might look like a bear to a bee. Do you think they might regard her as a threat? I’m reassured to read that the guarding ones don’t sting, as they look rather annoyed with me as I stand and watch them.

     
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Got a better look at them today. They have a white tail, black tum and ginger thorax, so most likely hypnorum. They are currently all over the snowberry blossom (Symphoricarpos Albas).

     
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Hi karenandmerry,

You have raised several points, so let’s take them in turn.

The bees going in an out above your door will almost certainly be a colony of the Tree Bumblebee, B. hypnorum.  They nest frequently in Bird Boxes, but commonly also in House Eaves and Soffit Boxes - the things behind gutters.  The fur colour you describe fits well and is an excellent identifier, but quite frequently I see much darker bees of this species and sometimes ones that can look mainly black, but with a white tail.

The nest won’t necessarily be close to where they are going in/out, because bumblebees sometimes walk a few feet to the nest.  It might be in an old bird nest, or maybe in a bit of loft-insulation, or Cavity Wall insulation.  They tend to be about 1 - 2 litres in volume, often much less and contain cocoons etc which look like an accumulation of tiny birds eggs.  (See if the BBCT Photo Gallery has some pictures, or check for videos on YouTube - there was an excellent one there last year.  Try searching for “Bumblebee Nest”, or “Bombus hypnorum nest”.

It sounds like the colony is strong enough to produce new (virgin) queens - which you are seeing as large bees - and they will be the start of a new generation colony, either later this summer, or next spring after hibernation over winter.  Not all colonies get this strong, so produce only workers.  If this species is like other bumblebee species, some colonies produce only male “reproductives”, some virgin queens only, others both.

Most of the bees you are seeing flying in the air above the door will be visiting drone (male) bees which are hoping to mate with a virgin queen.  These chaps sometimes collide and fall out of the air/ fall a short distance and you can sometimes hear a bit of a bang !  Sometimes I see them on a surface beneath my nest with one wing looking a bit dislocated, and they might be a bit “bruised” or winded too, but mostly they quickly pick themselves up and re-join the throng.  You should also see bees coming into the ‘cloud’ and others moving on to another site.

And also you are seeing a low level of smaller sized bee-traffic going out from and back into the nest “entrance” (flight -point).  These are the workers and they seem to ignore the crowd of drones in the air outside.  Workers can sting, which they can do if they sense their colony is threatened.  The sting is un-barbed, so the ‘bee-threatener’ gets a low dose of venom - just a quick jab - but humans find it painful and there may be some later redness and swelling. 

In humans, anti-histamine tablets will help reduce the symptoms.  Zirtek type anti-histamine tablets have 24 hour effect, whereas some of the older types (eg Piriton) have a shorter action.  Perhaps the majority of people probably won’t need to take any medication for a bumblebee sting.

In the loft the “strange pale lantern-shaped thing hanging from a rafter” will be an old wasp nest.  Lots of these get made in lofts, and die out before they get to full size, or are made by a wasp species that make just small nests.

Wax moth (Aphomia sociella) silk structures are like major accumulations of cobwebs inside the remains of a bumblebee nest, but eventually the caterpillars seem to move a short distance for the nest and build themselves a block of silk composed of dense tunnels lying close together.  It has the resilience of a piece of furniture foam and is incredibly strong and will be perhaps 10 x 5 x 3 (or more) cm in dimensions.  When still occupied it will contain a large number of caterpillars which are 2 -3 cm long and have brown heads with very powerful jaws.  There might be ~100 of them.  They can chew wood to make themselves a shallow scooped depression which fits the silk tunnel.  The caterpillars rest in the tunnels until the following year, then pupate.  The moths look like big clothes moths and are speckled greyish colour (the females) and can move very fast.  The males are much smaller and also greyish.

Your dog should be quite safe, being a long way from the nest entrance.  You, since you will be taller, might possibly be chased if you hang around too close while you are admiring the spectacle: but I regularly watch my colony in a bird-box from about 2- 3 metres away and have had little bother.

Since the flight point is above a doorway, if the bee activity gets to be annoying, you could consider diverting the bee activity zone to a less inconvenient place.  You can do things like this by (at night) fixing a piece of kitchen waste-pipe up where the bees are coming in and out, and using something like Duct Tape, or a pipe elbow etc ,to make the bees walk down the inside of the waste-pipe to the far end.  There would be a period of flight chaos until the bees have left enough scent-trace (from their sweaty feet) down the pipe and around the end of the pipe where they fly.  Bumblebees are fairly “plastic” in their location memory of where home is; and can fairly easily accept diversions like this.  You will need to work quickly, or you might upset any Guard Bees.  Doing it at night and working with red light (cycle rear light) will allow you to see what you are doing, but as the bees can’t see red, they will still think it is dark, so be much less mobile / ready to fly.

Yes, I’ve seen this species on Snowberry flowers in the past, but haven’t looked yet this year.  They have however been busy recently working the bright blue flowers of Green Alkanet in my garden!

I hope the above helps you and gives you some perspective about these bees - there is not much available about them in most bumblebee books, because they are pretty new to the UK.

Enjoy and, like me, be amazed and intrigued at the spectacle ! 

Yours Clive

     
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Hi saagmum,

Hopefully the long and detailed answer I gave above to karenandmerry will be helpful to you as well.
Don’t worry about blurred photos, you are looking for the fur colour combination, it doesn’t have to be all that clear to be useful !

Clive

     
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Hi Clive and thank you for all this fantastic information. I kept the old wooden fascia board rather than getting plastic board with soffits, when it needed painting recently, and I think this makes it a welcoming place for bees and birds. There was a robins nest a metre or two along a few years ago, before the magpie got him, so maybe that is what the bees are using.

In case of stings, I remember the rule that you put acid - lemon or vinegar - on a wasp sting, and alkaline (bicarbonate of soda) on bee stings. Presumably these tree bumblebee stings are like other bee stings in this regard?

The bumblebees are round the back too now, enjoying the roses which have all burst into bloom this week, after holding back with the cold weather. Actually I just went to take a photo, and they are ignoring the roses, and even the highly scented philadelphus, but are all over the blue geranium. There are a couple of honey-bees too, and the odd other bumblebee with a black body and ginger tail. Interestingly, the white-tailed ones feeding in the garden seem to vary in size - as if some drones are out feeding too. Could that be the case, or can the workers vary in size?

I will be careful not to intrude too closely in the bees territory. Your helpful advice on this was much appreciated.

     
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Here is one on the blue geranium.

     

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I was intrigued by this one today, with her great big pollen-bags (I’m sure they have a technical name). There was also a queen out, sleepily crawling over the philadelphus.

     

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Hi karenand merry,

To go back to your earlier post, lemon juice and bicarbonate etc may be a folk medicine, so have good placebo effects, but the active materials in bee stings are proteins, so not grossly affected. 
Go for an anti-histamine for a real sting-reducing effect !

Clive

     
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Hi again karenandmerry,

Pollen is carried around by bees in their “corbiculum” - plural corbiculae.
This is the latin word for a basket.
It is a hair-fringed area on the back leg and they use a structure called a Pollen Press to pack the pollen into the basket.
Try Googling it - there is much detail to learn, or forget !

Clive