Hi - I undertook my first beewalk yesterday, having recently done the FSC ‘identifying bumblebees’ course (and having been press-ganged into signing up by the BCT’s own Sinead Lynch!).
My first question is: I do not know how to tell the difference between acid, chalk/limestone, and neutral grassland. I can rule out chalk/limestone on my walk, but what key plant species do I need to find to distinguish whether the meadow grassland of my transect is acid or neutral? (For reference, it is Chingford Plain in Epping Forest, east London).
My second question is that I realised I was seeing female lucorum in a ratio of about three queens to every one worker. Can this be right? Even with new queens about, I’d still have expected to see a proportionately greater number of workers. Hence maybe I need to recalibrate my mental scale for the size at which I consider a female to be a queen. These ones weren’t huge but somewhere in between. I’d say about 17-19mm. And they weren’t males. And sorry, no I don’t have any photos…
If they were queens, then where are all the workers? Advice on separating queens from workers by size/behaviour would be appreciated, if possible.
Apologies for the lack of replies! I think this may be because it is quite tricky to answer!
I don’t know about the grassland flower species, but here are my thoughts about queen/worker sizes.
First - it is really variable!
It threw me when I first started my beewalk, and still does, at times, especially with common carders!
Bumblebee queen sizes varies with species, and also how well fed they were. Ditto with workers.
The first workers of the season are often particularly small. After that, they tend to get bigger, if the nest is being well provided for. As the nest grows, the smaller workers tend to remain in the nest and do nest-keeping/young-rearing duties, and the larger workers go out and forage. However, if the nest is struggling, or if the weather is poor/not much forage, the smaller bees will also go out to forage. This also seems to happen at the end of the season, as the nest begins to break down.
The size difference between workers of the same species can be really obvious.
So, when it comes to recording what I have seen on BeeWalk, I put down queen if it is clear (time of year, colour pattern in the species where this is different, and yes if it is just a huge one for that species!), and worker if it is clear. Otherwise, it is fine to put down in the ‘unknown’ column, and in the comments you can note that it was female.
You are probably getting much more confident by now, with several BeeWalks under your belt, and you may well have already got your answer. But hope this is of some help. Trust you are enjoying being a BeeWalker!
Species assemblages for acid grassland, etc, are on the JNCC website at http://jncc.defra.gov.uk/page-3559 As B.eehappy says, there’s often not a clearcut distinction between workers and queens, so when you’re not sure it’s best to put them down as unknown caste.