Sand Wasps to the Rescue!

Sand Wasp 5/8" long, J. Lampkin photo, Sep 2013

Hurricane Sandy may have done us a favor.  Have you noticed some low-flying bee-like insects hovering over the walk in the NE corner of the Garden by the fig tree?  These insects are definitely friends.  They are Bicyrtes quadrifasciatus, commonly known as Sand Wasps. And they would not be in the Garden if there was no sand for them to dig their nests.  The sand is there to hold the walkway bricks in place.  The brick walkways are a project that would not have been built if Sandy had not destroyed our original infrastructure.

Are they dangerous?  No.  Do they sting?  The females do have stingers.  They need them to paralyze the prey they lay their eggs on.  When the egg hatches, it has all the food it needs to grow into a working adult.  The males, who act quite aggressively until they realize you are not a wasp, have no stinger.  They act so to defend their territory in hopes of 'getting lucky'.  It is rare to be stung by a female sand wasp. She is far too busy finding prey for her young.  However, you might feel her sting if you step on her with your bare foot or put your hand on her.  Otherwise, feel free to walk through the little carpet of them in the NE corner.  Better yet, sit a while and observe them digging in the sand between the bricks, coming and going as they provision each chamber for the next generation. Watch this video of a Sand Wasp digging her nest burrow and another of a Female Sand Wasp dragging and carrying in a stinkbug for her young. A single female can kill 40 brown Marmorated stink bugs during its lifetime. 

The adults feed on the nectar they find in our flowers.  Thank them for helping with pollination.  But, a big thank you goes to them for the work they do when providing for their young.  And what is the favorite food choice for this?  True bugs.  In particular, Stinkbugs!  And what stinkbug has now started hatching in our garden?  The Squash Bug!  First sighting was June 28.  Last year they were everywhere.  Check your own zucchinis and other cucurbits.  Do you find clusters of bronze eggs under some of the leaves? If so, they will hatch and hopefully become food for the next generation of Sand Wasps.

Perhaps, if they run out of squash bugs, they will 'harvest' another stinkbug, that attacks our kale and other brassicas every summer -- the Harlequin Bug!

Sept 1, 2014
We've had no sightings of Harlequin or Squash bugs this summer after the arrival in June of the Sand Wasps.  This is in contrast to the heavy infestation of both during the 2013 season.  Last week I sighted a Sand Wasp on the walkway and it had something brown under it that it was holding on to.  Without disturbing her, I could only surmise it was a stinkbug she was stinging -- perhaps the brown marmorated one or the Squash bug.  Nearby was the sighting of recent nesting activity in the sand between the bricks near my plot.  Our Sand Wasps continue to be vigilant for this pest!  :> The Garden Sprite

Dec 2, 2017
Today I was surprised by the sighting two Harlequin bugs in my plot.  They, along with the Squash bug, were more abundant this summer than in 2014. One was on the ground and one on the red Russian kale I had cloched. The weather has been unusually warm this fall, but in the lower 30's a few days this week.  I dispatched what I hope is the last of these bugs for the year.  They are heartier than I thought and sure to return next year!  But the Sand Wasps were also still at work here this year.  The holes in the sand between our bricks gave their activity away.  And so, we rely on our chitinous friends to help keep our chitinous 'enemies' in balance. :> The Garden Sprite

Oct 15, 2018 
The Harlequin bugs have been multiplying on our brassicas and the mild fall weather has been a good  encouragement to their endeavors!  The Sand Wasps are nowhere in sight.  Most of the sand between the bricks has been replaced with dirt spilling out from our plots.  We may need to build a sandbox nursery to encourage them to come back and nest with us!  :> The Garden Sprite