Alien Invasion

Last year was a big year for cicadas.  Their whirring hum was a constant backdrop for any outdoor activity.  It was also the first time we became acquainted with cicadas' natural predator, a variety of wasp uninterested in typical wasp-like behavior -- that is the unprovoked and incredibly painful stinging of hapless humans.  This species, whose official name is Sphecius speciosus, is commonly referred to as cicada killer because its sole (and rather perverse) purpose is to keep the population of cicadas under control.  Couldn't we have skipped this symbiotic relationship altogether and reduced the count of the insect world by two species -- who would have noticed?


In any event, we first saw a couple of these bugs last year.  They're hard NOT to notice.  The females are the larger of the two genders and they're the insect equivalent of a C-130 Hercules cargo plane.  They're huge -- about 2" long and bigger than some hummingbirds.  It's hard to get a sense of scale from this picture, but trust me, she's ginormous.

The females have stingers but use them primarily to stun their prey, though they will defend themselves if you step on them.  The males, smaller and a bit nimbler (more like a B-52), have no stingers and spend much of their time wrestling in midair with one another over who gets to date which lady.


We adopted a benign attitude towards them last year.  They reciprocated.  A good time was had by all.


This year, not so much.


It turns out that the bountiful cicada supply of last year was used to nourish a bumper crop of cicada killer larvae who slumbered through the winter and emerged in legions this summer.  And this year's population has been busy getting ready to multiply exponentially -- even though the cicada pickins' are slimmer.  And how do we know this?  Because these insects don't cover their tracks.  At all.  They burrow into sandy or dry soil, excavating huge mounds of debris with a telltale tunnel down into an insect catacomb where they deposit larvae in multiple cells, walling each in with one or two cicadas (dead) to serve as their room service meals throughout the winter.  


This is not a problem if you have a patch of barren soil in an inconspicuous place in the corner of your backyard.  However, on our property the only dry sandy soil is between the flagstones in the patio.  In the middle of our outdoor dining area.  Which now looks as though a small army has been digging foxholes and preparing for battle.

They have heaved up at least half of the patio. The dining table, no longer level, now sits at a rakish angle and corn cobs roll off it if you don't pay attention.  And although we know that they don't sting, it's still unnerving to have half a dozen of these dirigibles buzzing our heads as we try to enjoy dining al fresco.  And unless we do something about these larvae-filled mazes below the patio, next year we'll have to start setting places for them at the table.  Any suggestions?