Bembix  (Bembix americana?  There are several species.)

A Google book report

Otis Redding sat on the dock of the bay, watchin’ the tide roll away. Jimmy Buffet nibbled on sponge cake watchin’ the sun bake. Yesterday I wasted away in Juno Beach-a-ville watchin’ a sand wasp. One of the best parts of botanizing is spotting cool creatures, from anhingas to zebra longwings, and then using the internet to research their stories.  Today’s object of wonder was a splendid piece of creation, a sand wasp digging a burrow in the dune sand.

Click  for a speedy peep at hot digging action!

Where does it find the energy to dig like that under the 94-degree sun?   The wasps have  two forms of nutrition:  nectar and prey.   They visit flowers, and I’ve read they prefer white ones.   Are most scrub flowers white?   Yea, no, maybe so…at least many are.  As with so many fascinating Florida insects, today’s is not well studied, and no doubt has its secrets including mouthparts adapted to collecting nectar.

In addition to floral nectar,  the sand wasp is a little buzzbomb designed for nabbing prey, although  the range of victimized species seems to be one of the wasp’s secrets.  Googling leads to “flies.”  Somebody even said that sand wasps hanging around humans are not interested in the humans, but rather in the flies they attract.  I dunno. Would like to think I don’t often attract flies.  But in any case, the sand wasps are not belligerent.  Just the opposite, they let you sit there broiling in the sun watching them come and go.  Seeking mates? Shooing competitors?  Nabbing  flies?  Sucking flowers?, and dig dig dig.   

The wasps are solitary and ground-nesting.  The female provisions her tunnel with the prey insects as larval food.   Usually the female brings a victim to the nest and lays an egg on it.  Like a mother bird, she can then return to the burrow repeatedly with supplementary provisions. I can’t even remember where I leave my car keys.

The one I watched yesterday had two behaviors in addition to digging.  One behavior was backing into the burrow for brief periods, okay: shady, moist, and restful.   The other behavior was more puzzling:  she would fly away and return all within maybe 20-30 seconds if that long.  The flights were too brief for floral visits or fly-catching, and she always returned empty-handed.   Maybe my presence was disturbing, but unlikely—the short flights had no apparent relation to me.  Mating was the likely motive.   After all, no tunnel nest is complete without a fertilized egg.   The males cruise around near the ground looking for hookups, so maybe the female’s brief sorties are procreational.