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possible cuckoo bee?

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Joined 2017-01-17

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I saw a number of bees at Minsmere in August that I think may be cuckoo bees.

I can’t upload the photos here but they are on my blog

http://dorsetdipper.blogspot.co.uk/2017/01/bee-id.html

Longish abdomen, yellow on the flanks, no pollen, possibly Gypsy Cuckoo Bee or Vestal Cuckoo Bee?


thanks for any responses

     
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Total Posts: 340

Joined 2013-01-10

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Hi John,
Welcome to the forum.
As you say, the bumble in your blog pic is a cuckoo bumble, foraging on a thistle species - no pollen baskets - however, as to which of the 2 species you mention -  its not always possible to split i/d from a pic ....  although it does have yellow flashes adjacent to white tail etc.  Its wings look a bit ragged at the edges - probably old & worn, therefore possibly faded colours .......  Here in VC55,  Bombus vestalis [Vestal Cuckoo Bee] tends to be the more regular option each summer , with Bombus bohemicus [ Gypsy Cuckoo Bee] less common, even though I often check for the antennal segment [3 & 5] differences between the two to make sure if necessary [need a captive bumble & a x10 handlens to do this - can’t do it with a pic].
Perhaps someone else on this forum can offer an opinion as to your bumble’s identity? Otherwise check out all the information elsewhere on this BBCT site; or bumblebee identification books such as by Steve Falk;  - and Mike Edwards.    or is there a bumblelist for Minsmere?  Keep bumble watching in 2017.                   
urbanbumble

     
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Joined 2017-01-17

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urbanbumble - thanks for your reply. Really appreciate your expertise here, and quite excited to have found a cuckoo bee even if its not clear which sort. There were quite a few of them on the thistles.

     
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Joined 2014-02-14

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Hi John,
As Urbanbumble says, that’s definitely a cuckoo, one of vestalis and bohemicus.  It’s a male, so the antennae are the way to go (females need you to look at the underside of the abdomen instead) but your pictures don’t show this quite well enough to call it. 

However, bohemicus seems mainly to be parasitic on magnus and cryptarum, less so on lucorum, whereas vestalis is parasitic on terrestris.  As magnus and cryptarum will be considerably less common than terrestris at Minsmere that tips the scales towards vestalis.  Check thistles or other big sturdy nectar-producing flowers between June and August and you should find some more!