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3 Ocelli

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Just looking at a photo from last year and was wondering what purpose the 3 Ocelli have…..
Are they for thermal imaging or flight navigation / orientation ?
The photos are not the sharpest in the world but they can clearly be seen between the 2 compound eyes.

     

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Hello Peter,

I’ve been meaning to come back with some comments here, but not been organised to do so until now.

I too have some photos which show bumblebee ocelli, but I haven’t yet worked out how to send in photos - must learn soon !

I’m a Beekeeper and when I saw your note I checked in some of my honey bee text books.

I found that Ocelli were thought to function as overall light level sensors. 
Honey bees whichhad their ocelli painted over experimentally were much slower to start foraging than bees with unobstructed ocelli.
And here, later foraging was judged to correspond to brighter light levels.

Also, my memory says that I’ve picked up somewhere that ocelli tell a bee what direction is ‘up’ - where the sky is a brighter source of light than landscape or vegetation.  Snow can cause havoc here, because a snow surface reflects much light and can cause the bee to move towards an ‘up’ which is actually the cold surface of snow.  Once they’ve ploughed-into snow, honey bees quickly chill and die.

And I’m assuming that what happens in honey bees is the same for bumblebees - but they forage in much lower light levels than honey bees.

Clive

     
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Hi Clive,

Thanks for that…... It’s nice to know that my thoughts on orientation / navigation are not a million miles from be being on the right track !

Peter

Ps .. just posted an answer to Venessa (B Hyp;) similar to yours, not realising the thread has now gone on to page 2… so, apologises to you.

     
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Hi Peter,

Thanks for your comments.
I should have replied ages back, but I couldn’t remember which thread this message was under - but have now found it !

Yes, in some ways it would be useful if lengthy threads could be reversed at the click of a mouse, which would make it easier to read new inputs.

Clive

     
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Hi Peter,

I have been following this post, and was hoping that I may have your permission to use the photo of the bee in the next Bumblebee Conservation Trust newsletter. Ican be contacted at .(JavaScript must be enabled to view this email address) if you have any questions.

Regards,
Anthony
BBCT Outreach Officer

     
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Hi Anthony,

Thanks for asking….... Yes, it would be nice to see it in print !

Kind regards…. Peter

     
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Hi Peter,

Thanks for giving us permission to use it. Are you a member of BBCT? If so, you’ll have just received our latest Buzzword newsletter, with your photo in it. If you haven’t I can post you a copy if you email me your address (email to .(JavaScript must be enabled to view this email address)).

Thanks,
Anthony

     
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Hi,

I read that Wellington (1974) said “Western bumblebees fly straight while homing by polarized light, but zigzag when they use landmarks. That flight difference was used to determine the roles of the dorsal ocelli and parts of the compound eyes in homing. Polarized light and ocelli can prolong foraging at twilight, when landmarks are no longer visible.”  I couldn’t find the full text article, but here’s the reference -
http://www.sciencemag.org/content/183/4124/550.abstract

The Western is a US species, I wonder if them same can be assumed of those in the UK ?

     
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Hi Platdujour,

Thanks for the link to ” sciencemag”, I shall have ago at trying to wade through the info; from the various other links it contains.
Could be that some of it will go straight over my head….. comes from having a brain like a sieve !

Many thanks….... Peter