Hovering Hymenoptera

Observations at a Volleyball Court, accompanied by an ID & Behavioral Challenge

While on holiday in Oklahoma this weekend, I happened by this volleyball court on the way to the pool.   My attention was immediately drawn to movements that I observed in my periphery.  Here is what I observed from sand level…

and close-up from above…

The species may be territorial.  While individuals came close to each other it appeared like there were brief chases and overall there was an emergent spatial pattern (I think you can see it in the first video) suggestive of territoriality.   I tried to follow the movement of a single individual but it was too difficult for me.

After spending more time, continuing to ignore my children swimming and doing flips of the side of the pool, I made these more detailed observations suggestive of territoriality as well.  In the first video, you will see interactions between numerous live individuals with a single dead individual of the same species…

Here is a close-up image of an instance of this behavior…

In the second video, you will see interactions of these hymenoptera with a mottled leaf…

Here is a close-up image of an instance of this behavior…

The fact that the colors of the leaf are similar to some of those found in the wasps themselves made me wonder if I could elicit the behavior with another leaf.  The leaf I chose to use, unlike the one I found them naturally interacting with, was entirely yellow.  What do you hypothesize will happen?

Around the periphery of the volleyball court, I noticed holes in the sand that were approximately the same diameter as the cylinder shape of the insect themselves (see below), although maybe a bit weathered.  I should have dug them up but didn’t think of it at the time.

I had noticed similar behavior in a much smaller number of cicada killers in a children’s sandbox, but had no idea what type of hymenoptera this species was.  Similar, I wondered, was this a mating swarm?  Where they recently emerged individuals?  What was the ratio of genders?  How long does this behavior persist?  What resources might they use to maintain their energy?

A few curious individuals did happen to come by while I was making my observations, and I received seemingly conflicting reports on their longevity.  One adult mentioned that they are there all the time, while a couple of kids arriving to play volleyball hadn’t noticed them there the day before.  In fact, later that night I saw, from afar, four people playing volleyball.  I might add, that to get some of the images and video, I walked in amongst the swarm.  I did so slowly but felt that they may have ignored me even if I had walked in at a normal pace.

So, here’s the challenge…

  • What is the genus and/or species of this hymenoptera?  and
  • What the heck are they doing?

As mentioned in response to Brad’s post on aphids, I think a collection of such videos and images could make an interesting series of ecological activities for students, and possibly a series of models for them to produce their own reports, blogs, etc… on interesting outdoor observations that can motivate learning of particular ecological principles.

For anyone that responds with the answers, unknown to me with any certainty, it would be nice, and potentially helpful in the future, for you to provide links to websites that helped in your identification.