obliging enough to pose…

Author Deb Taylor ◦

This wasp was first sighted moving across gravel and mulch on the ground (as shown in last 3 photos) but after flying away alighted in a nearby Cotoneaster where it stayed for quite some time.

kerrileeharris suggested an ID
Bembix palmata, a member of Sand Wasps Tribe Bembicini
The shape of the front tarsus is distinctive in this species, and it ticks all the other boxes too. Notably, the shape of the clypeus and labrum, and the overall colour pattern.

I’m currently putting together some notes on this genus, for reference, but it will be a few more days before they’re finished. In the meantime, this has been a great opportunity for me to test my summary table (matrix) … and it worked! 🙂

debtaylor14
Thanks kerrileeharris for both your kind words and a potential ID 🙂 I can’t begin to tell you how excited I was to spot this little beauty! The colours on it were extraordinary, and I was particularly taken by the blue banding on its abdomen ….. not even striping as I usually see on other striped insects but a little bit squiggly so they looked as though they’d been drawn by an unsteady hand. I note that these wasps are predatory, and particularly so of flies? Perhaps it made its way up to the flowering Cotoneaster because it was buzzing with lots of insect activity and lots of potential snacks.

Bembix palmata, a member of Sand Wasps Tribe Bembicini…
Fantastic! Great to have an ID on this one ….. thanks so much.

kerrileeharris
mmm … not this one. It’s a male, so he’ll only be after an occasional nectar feed. He ate his fill of flies as a baby (ie larva) 😉

debtaylor142
Ah! Good to know 🙂 How are you able to identify this one as male? Asking since you’re the one with the matrix ….. and all the knowledge 😀

Oh wait ….. if it was a female it would have an ovipositor? Asked the question before I put my brain into gear.

kerrileeharris
Well, yes it would, but not an easily seen one. The ovipositor is only obvious (strongly exserted) in some wasp families, and not in Crabronidae.

With most crabronids, there are two clues to sex: the number of antennal segments, and the number of visible metasomal (‘abdominal’) segments.

in Bembix and most crabronids (but not all), males have a total of 13 antennal segments (scape, pedicel, then 11 flagellomeres). Females have just 10 flagellomeres). These are not always easy to count, and in your wasp the terminal segments are quite small, but Photo #4 shows them rather nicely.
again, metasomal segments can be tricky, as the apical ones can be small and tucked away. But there are clearly 7 here … females have just 6 segments visible dorsally.

In addition, in some species of Bembix (including B. palmata), there is a medial ridge or other elevation on the second sternite (ie 2nd segment of abdomen, ventrally). It shows up nicely in Photo 4.

debtaylor142
This is great to know for future reference Kerri-Lee 🙂 Chuffed that I was able to get images that show the features of a male so nicely. It helps when the subject is obliging enough to pose for a multitude of photos from multiple angles ….. unfortunately, as I’m sure you are aware, it often isn’t the case.