orchid_b's picture

Telling female lucorum from male terrestris

Observed: 3rd August 2013 By: orchid_borchid_b’s reputation in Invertebratesorchid_b’s reputation in Invertebratesorchid_b’s reputation in Invertebratesorchid_b’s reputation in Invertebrates

The bumblebee books don't tell you how you actually i/d in the field. They always start 'Count the segments on the antennae'. This is great for a dead bee in a museum, but useless in the field. What you actually do is 1)know what females, males and workers are about and 2) work out the possibles from the main pattern and a process of elimination.
Pretty much any of the six common spp can be i/d by doing this without counting antennae segments - except male terrestris and female lucorum, which have basically the same pattern: black face, single yellow stripes thorax and abdomen and white tail. This can be buff in male terrestris, but can be pretty gleaming white as well, and it is these that are the problem.
As these are the two most common species, you'd have thought the i/d books would think to mention how to tell the two main confusion-forms (at this time of year) apart, but no.
However I have worked out one way which you can even use without catching sometimes: hair colour on the hind tibia.

Species interactions

No interactions present.

Species with which White-tailed Bumblebee (Bombus (Bombus) lucorum) interacts


Mydaea's picture

The problem is that 'lucorum'

The problem is that 'lucorum' is not a single species. There are at least two and maybe four species under that name and no-one knows how to tell them apart reliably without chemistry. Also there are continental white-tailed terrestris that look like 'lucorum'. A little experience will identify sexes without counting segments. Any significant buff in the tail of a 2-banded bee makes it terrestris (unless of course it is magnus or soroeensis, which you will have in Dorset and many other places). All white and you have a problem that can't be solved in the field. Whoever told you identifying Bombus was easy, or that you only had to consider lucorum complex and terrestris was wrong.

orchid_b's picture


I'm not quite sure what your point is here, but whatever it is I don;t think you've chosen the best example to illustrate it. It's like saying that because dandelions are hard, you have to start by keying out every yellow composite you see. As with dandelions, B.lucorum agg. is fine for most of us to record in our gardens and most non-specialised habitats, and I will leave any further i/d to the Dead Bee Society until some useful reliable field characters have been worked out.

If I was lucky enough to get soroensis, I think the peach-coloured band would alert me if there were several about.

It might be worth starting a forum thread on this - I'll put a note back here if I do.

Jamie from Briantspuddle

Mydaea's picture

The point is that field

The point is that field recognition of Bombus is not easy, and assuming (as you seemed to do) that two-banded females are either terrestris or lucorum s.s. is wrong. If you are looking for a 'peach-coloured band' to identify soroeensis you may well be overlooking them - you would not be the first - as many females have a completely white tail, and they are not by any means averse to gardens in the right area and habitat.

orchid_b's picture

Well, I'll look out for them

Well, I'll look out for them - but I'm not holding my breath.

Going back to my original para, I take it then that you would disagree with Ted Benton in the New Nat Bumblebees, who was attempting to do just that: recognise that by far the majority of us will most regularly encounter the common six (now seven with hypnorum) species, and therefore to sort out their i/d first. He pointed out this difference in hind tibial hair colour in male & female terrestris, in fact, which I was hoping to develop to include lucorum (and no he didn't worry about ss/sl in this part of the text).

What I was hoping for from Ispotters was helpful comments on my suggestion that this would be a good field character, viz. 1) Yes it is, or 2) No it isn't as there are exceptions. If we then have to add an atypical form of a localised species into this, then OK, what extra field character/s would we look for?

I do agree with you that field i/d of bumblebees here is difficult, but feel this is more due to the quality and approach of the field guides than the bees themselves. I'm posting a rupestris shortly to further support this point.

Jamie from Briantspuddle

Mydaea's picture

"Well, I'll look out for

"Well, I'll look out for them" - Good - you will never find them otherwise (a number of soroeensis were found in the NHM collection, under lucorum; if the NHM can confuse them you can, and they are more widespread than you might think).

"I take it then that you would disagree with Ted Benton" - No I don't disagree.

"he didn't worry about ss/sl in this part of the text" - He mentions cryptarum and magnus on pp316-18, and life has moved on since 2006.

"What I was hoping for from Ispotters was helpful comments" - I think you have had them.

"field i/d of bumblebees here is difficult ... more due to the quality and approach of the field guides than the bees themselves" - You can write as many field guides as you want, but the anatomy of the bees will remain the same and some (like lucorum complex and terrestris and the brown Thoracobombus) will always remain impossible or difficult to identify with certainty in the field.

eucera's picture

ID Comment

B. magnus is one of the B. lucorum group!

What the guide books are actually saying is that species level id in the field is extremely difficult, and in the case of workers of terrestris/"lucorum" often impossible. However much we might want it otherwise.... this is how it is (until we all have hand-held DNA barcoders).

Chairman BWARS

orchid_b's picture


Yes, as I mention above, I am happy with lucorum agg. until reliable field characters have been worked out - maybe it is a case of looking for extreme examples of say magnus if there are a lot about.

Your point about workers I think supports what I am saying - which is that basic Bombus i/d could do with a bit of de-mythologising. Most of us backyard bee-watchers are happy to record lucorum/terrestris workers as such, only going to species level with the queens and males.

I've been trying my pale hairs on hind tibia character for field i/d of male terrestris v female lucorum and I think it works pretty well - better than counting antenna segments anyway!

I may start a forum thread on Bombus i/d - will post a link here if I do.

I hope to post a vestalis/bohemicus with more controversial comments later this evening!

Jamie from Briantspuddle