Bee ID and Behaviour Insight please?

[ste_]

Hi all,

We recently, last Wednesday, visited a climbing venue in Northumberland that we'd visited numerous times before and came across something that isn't a common occurrence.

I several areas along 400m+ of the crag we noticed clusters of the bees I am including photographs of; they numbered perhaps a couple of dozen, were unperturbed by our presence; flitting around between several clumps of little burrow entrances; some occasionally entering burrows, some occasionally exiting, most just pootling around.

I wondered if you could help me with a few things:

a.) Identification - we've got as far as thinking they may be Andrena spp. but are far from sure.

b.) Does anyone know what they were doing?


Many thanks,

Steve

[ste_]

PS Apols in that the above images are sourced off-site: I have submitted these to the Gallery but the mods must be busy. Unfortunately I'm really curious and would like to resolve this, for now, I've sourced off-site, sorry.

[aeshna5]

I think they are Andrena flavipes, which I think have 2 broods/year. They are a gregarious solitary bee (sounds like an oxymoron!). If I'm wrong Eucera, our bee expert, will put it right!

Some mating going on in at least 1 photo!

[eucera]

These are Colletes succinctus, a solitary bee that nests in dense aggregations in northern England and Scotland (less densely in S. England). The bees are almost entirely dependent on the pollen of Calluna vulgaris (Heather). Occasionally, there are populations that will visit yellow-flowered Asteraceae, but this is really rather rare. The bees are very common wherever heather grows and there are suitable nesting sites.

All the bees in your pics are males and they are hanging around the burrow entrances waiting for the emergence of females.

Could you please pm me with the where, when and who details of these. I should like to add this info to the national dataset

[ste_]

Many thanks to you both!

My friends and I had narrowed our own attempts (trial and error) at i.d. to what we thought was the Andrena genus. When aeshna5 suggested flavipes I rummaged around the web and was happy with that. However, when eucera named them as Colletes succinctus and I web-browsed, it was an immediate "yes, spot on".

To me the two species look similar, eucera can I ask you was it anything in particular that enabled you to differentiate, or more a case of overall/general recognition?

Many thanks again, I will pm the info requested.

[ste_]

Originally Posted by ste_

PS Apols in that the above images are sourced off-site: I have submitted these to the Gallery but the mods must be busy. Unfortunately I'm really curious and would like to resolve this, for now, I've sourced off-site, sorry.

Oh well, the images have been approved but I can't edit my first post, not to worry - will do better next time

[eucera]

Originally Posted by ste_

Many thanks to you both!

My friends and I had narrowed our own attempts (trial and error) at i.d. to what we thought was the Andrena genus. When aeshna5 suggested flavipes I rummaged around the web and was happy with that. However, when eucera named them as Colletes succinctus and I web-browsed, it was an immediate "yes, spot on".

To me the two species look similar, eucera can I ask you was it anything in particular that enabled you to differentiate, or more a case of overall/general recognition?

Many thanks again, I will pm the info requested.

Well... yes! First is the indefinable jizz gained form 20 years of experience in dealing with solitary bees in UK and across Europe. However, that isn't much help to you I suspect.

Andrena flavipes is southern in distribution and is unlikely still to be flying, even where it occurs. The species has a spring generation in March-May and a summer brood from Late June to early August.

Colletes succinctus is a classic late summer bee of heath and moorland, and is very obvious in the vicinity of its nesting sites. I have been on south coast saltmarsh fringes these last 2 days and found its BAP-listed relative C. halophilus in a new locality, feeding on Sea Aster, its key forage plant.

By and large, Colletes are a very uniform genus, with a basic body shape and patterning. You should look at my friend Nico Vereecken's page of pics:
Colletes - a photoset on Flickr

On a techical level... Colletes bees have 3 sub marginal cells in their fore-wings, a short, bilobed tongue, and an S shaped vein near the outer margin of the forewing (just about visible in the pic 1 from the bottom of your series.

Best wishes, Stuart