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How long is a long tongue

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Joined 2012-11-09

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How long is a long tongue?
Edwards and Jenner describe the tongue of the Buff-tailed Bumblebee (B. Terrestris) as ‘very short’ and that of the Common Carder (B.Pascuorum) as ‘long’.  Worker bees of both species have been visiting my nasturtiums this year and sometimes both hover with tongues out a little way from the flower before going in.  To me the tongues seem to be about the same length, (roughly a centimetre).  Can anyone give me a guide as to the length of a long or short tongue?  I’m still trying to catch one with tongue out on camera!
Kit

     
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Joined 2012-05-24

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Hi Kit,

There’s a New Naturalist book by Proctor, Yeo & Lack.  I think it is called Pollination, or some such.
It was published in 1996.  It might be available now as a soft-cover re-print.

It contains a fascinating table listing a range of bee species and their tongue length.

Here is what it said about Bumblebee Queens :-
The first column in Body Length mm.
Second is Tongue length.
Third is tongue as % of body length - and if my memory is right this is an extra value that I calculated from columns 1 & 2.

Bombus pratorum 16       10 - 12     75
Bombus terrestris 22       14           64
Bombus lapidarius 24       10           42
Bombus pascuorum 15 - 17   11 - 14       82
Bombus hortorum 20       18 - 19     95

I hope this gives you some idea !
Workers of course vary significantly in body size and so in tongue length !

Clive

     
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Hi Clive, 
Thanks for your helpful reply and calculations.  Sadly probably not many more bees now till next year.
Proctor’s figures do seem to disagree with Jenner and Edwards re B. Terrestris’ ‘v. short’ tongue. In your calculations of percentages, B Terrestris come second from shortest, but still longer than B Lapidarius which J and E call ‘mid-length’. A bit confusing, but all adds to the fun -  and room for further study!
Kit

     
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Joined 2012-05-24

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Hi Kit,

I came to bumblebees from being a Beekeeper and honey bees are remarkably standardised body-wise.
BBs though are variable between the different species and also within a species.
And it took me some time to grasp the complexity that results from the within-species variation.

Staying with one species, body size and tongue length must vary within queens and even more so with workers: but perhaps it means that they can work a bigger spectrum of flowers - since flowers vary in size too !

Goulson’s book “bumblebees behaviour, ecology and conservation” has many references to tongue length and a chapter (11) about Competition and Niche Differentiation in Bumblebee Communities - which looks a good place for you to start reading !

Yes, BB numbers in my locality have now dropped off enormously, but I’m still seeing B. pascuorum working a range of flowers and also B. hortorum seems to be coming a few times a day to visit Morning Glory flowers - which must mean there is a second cycle colony somewhere about.  In recent weeks there have been B. pratorum and B. terrestris workers about too.

Yours,      Clive

     
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Thanks again, Clive. 
I have Goulson, but hadn’t yet reached chap 11, there’s a lot to take in.  Certainly interesting on tongue length in chap 11 and other refs.
Here we’ve still just pascuorum visiting Michaelmas Daisies and purple toadflax in garden and clover on the common heath land.
Kit

     
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Postscript
Warm late September day. B. Pascuorum visiting Michaelmas Daisy 3 or 4 at a time through the afternoon after only occasional visits for some weeks.  The one in the photo (I think a male) showing a long tongue in action.
Kit

     

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