Andrena sp?

[jezlee]

Hello all - I collected this bee off Knapweed earlier today. Size was probably around 10-15mm (from memory, I didn't measure! ) Is it one of the Andrenas do you think?

[eucera]

Megachile - check out the pollen collecting hair on the underside of the abdomen

[Jason Green]

Afternoon Jez,

I like the neutral setting! Well done on the approach. As for what it is, it has one too few sub-marginal wing-cells. The position of the scopal hairs put it in Megachilidae, and the tarsal claws if facing the right way would have visible areolae. This is I believe an Osmia species which I always recognise as such by the big head! It's a habitus thing, quite unmistakeable.

As for species-level, no idea. I've tried several times with various hymenopterists to get recommendations on lierature, but haven't had a reply. I think some bee-book is coming out some time, but I find it all rather frustrating having several myself that I'd like named. I don't have this problem with other orders - just Hymenoptera! Annoying, since it's a group I'm becoming increasingly interested in.

Keep up the good work.

Take care,

Jason

[Matt Smith]

As Eucera said - its a Megachile species.

[Jason Green]

Do you have any further images of the tarsi, Jez? The fore-tarsi on yours looks to have an areola, and the gena too deep for Megachile in my opinion.

Having checked both a Megachile, and an Osmia specimen with orange scopal hairs, at various angles it's only my Osmia showing anything between the claws. The depicted individual's claws look too short - Megachile are usually longer and straighter. None of my Megachile specimens have deep orange mandibular hairs but are a notable feature on my Osmia.

[jezlee]

Originally Posted by eucera

Megachile - check out the pollen collecting hair on the underside of the abdomen

Thanks, eucera - I have noticed these on flowers and watched them sweeping their legs up underneath their abdomens and wondering if they were collecting pollen somehow. That would explain it!

[jezlee]

Originally Posted by Jason Green

I don't have this problem with other orders - just Hymenoptera! Annoying, since it's a group I'm becoming increasingly interested in.

You and me both, Jason - this year I made an effort to plant more bee-friendly flowers in the garden and it has already made an impact, especially attracting larger numbers of 'solitary' bees. I also put up a 'bee-house' for the first time and am pleased to say that it has already been used (several of the ends of the bamboo tubes are sealed up!). I also saw my first Tree Bumblebee in the garden a couple of weeks ago!

[jezlee]

Originally Posted by Jason Green

Do you have any further images of the tarsi, Jez? The fore-tarsi on yours looks to have an areola, and the gena too deep for Megachile in my opinion.

Having checked both a Megachile, and an Osmia specimen with orange scopal hairs, at various angles it's only my Osmia showing anything between the claws. The depicted individual's claws look too short - Megachile are usually longer and straighter. None of my Megachile specimens have deep orange mandibular hairs but are a notable feature on my Osmia.

Thanks for all your help, Jason!

I suppose this is where having specimens to refer to is a bonus - as long as you know you have correctly identified the specimens to which you are referring, I suppose!

[JRsbugs]

Originally Posted by Jason Green

Do you have any further images of the tarsi, Jez? The fore-tarsi on yours looks to have an areola, and the gena too deep for Megachile in my opinion.

Having checked both a Megachile, and an Osmia specimen with orange scopal hairs, at various angles it's only my Osmia showing anything between the claws.

None of my Megachile specimens have deep orange mandibular hairs but are a notable feature on my Osmia.

The morale of this is, don't judge until you have far more experience.

[Jason Green]

Originally Posted by JRsbugs

The morale of this is, don't judge until you have far more experience.

We haven't concluded yet!

Well, a useful image of Osmia rufa there. I took the liberty of editing that in with Jez's, both of which show the tarsal claws either folded under the insect or pointing outwards and in both the case of yours and his, you'll see the areola in contact with the ground:

...but as I said, I identified Jez's on the basis of habitus in it being more Osmia-like, then used the claws for confirmation. Note how the eyes are rather forward-produced for one, leaving a comparatively wide gena. This is a female; perhaps with the odd exception they usually have short adpressed whitish hairs clothing the hind margins/marginals of the tergites. Looking here, you'll see they're long, scattered and semi-erect. Can anyone see a lustre to the uniformly-punctate surface?

You're probably right in what you said about the orange mandibular hairs in the case of your photos. I don't have rufa, and based it on my Osmia that's the same Megachile-looking one. My Megachile don't have the same degree of orange hair coverage on the mandibles that I find on my Osmia spp.