I was very happy to come across a huge bumblebee whilst walking on the heather-clad hills of Galicia in NW Spain. To be honest I have never seen such a big bumblebee. It really was huge. White-tailed bumblebee  (Bombus lucorum) queens are supposed to get up to a maximum of 22 mm (less than an inch), but this bee seemed to be much larger than that. Perhaps it was my imagination, or do they get larger in Spain?

I always find identifying bumblebees a bit of a challenge, but I am fairly sure that this was a White-tailed bumblebee queen. The yellow bands were more lemon-coloured than orange-yellow (as in B. terrestris) and the tail was a very clean white. It was also up in the hills, which is typical of Bombus lucorum in Europe. (1)

Bombus lucorum is a species complex comprising three taxa (called B. lucorum, Bombus magnus and Bombus cryptarum), but it is rather unfortunate that they cannot be separated from one another by just their morphological characteristics. It seems that a combination of morphological, physiological and molecular characters are needed! (3, 4) Not much hope of the field naturalist separating them then! Or is there?

“Morphological, physiological, and molecular operational taxonomical units (OTUs) clearly separate the specimens of the Bombus lucorum complex into three clusters that correspond with the taxa defined as B. lucorum, B. cryptarum and B. magnus” (Bertsch, 2009).

There are references to the fact that Bombus magnus queens are bigger than B. lucorum queens (2) and it seems that this species also likes moorland (5). So perhaps this lovely insect was Bombus magnus (?) and I was not imagining the huge size, it really was a big ‘un! On further reading however, I discovered that there seems be some doubts about the validity of the older Spanish records for Bombus magnus (6), even though there are some nice yellow dots in exactly the right location on the Atlas Hymenoptera map for this species (1).

After I had taken these photographs, I wished I had stepped back a little and tried to get a shot of the bumblebee in context with the heather, which might have illustrated its size a little better.

One thing which struck me whilst looking at these photos, is how worn the wings are. The left fore-wing looks more like an oar! (See above). Yet the bee seemed to be flying perfectly well. In fact in one shot (below) she almost appears to be flying on one wing! This could be an effect of the fast shutter speed however: 1/1,250 of a second.

The more we know about the habits and behaviours of bumblebees such as this, then perhaps we can separate the cryptic species without the need for bar-coding? Call me old-fashioned, but it would be nice to be able to identify species in the field without resorting to a medly of  ‘operational taxonomical units’. Perhaps we just don’t know enough about them to be able to recognise them?

These photographs were taken near a look-out point called, Mirador Da Miranda, above the town of Cariño, in the province of A Coruña, NW Spain.

It is a gorgeous location in late summer when the heather is blooming.

Links and references

1. http://www.atlashymenoptera.net/page.asp?id=169
2. https://en.wikipedia.org/wiki/Bombus_lucorum
3. Bertsch, A. (2009). Barcoding cryptic bumblebee taxa: B. lucorum, B. crytarum and B. magnus, a case study (Hymenoptera: Apidae: Bombus). Beiträge zur Entomologie= Contributions to Entomology, 59(2), 287-310.
4. Carolan, J. C., Murray, T. E., Fitzpatrick, Ú., Crossley, J., Schmidt, H., Cederberg, B., … & Brown, M. J. (2012). Colour patterns do not diagnose species: quantitative evaluation of a DNA barcoded cryptic bumblebee complex. PloS one, 7(1), e29251.
5. Falk, S. J. (2015). Field guide to the bees of Great Britain and Ireland. British Wildlife Publishing.
6. Bossert, S. (2015). Recognition and identification of bumblebee species in the Bombus lucorum-complex (Hymenoptera, Apidae)–A review and outlook. Deutsche Entomologische Zeitschrift, 62, 19.