Naturespeak A naturalist's view of the world

June 17, 2007

The Ways of the Water Wasp

Filed under: Uncategorized — wykes @ 10:54 pm

  Somehow, I find it comforting to know that there are creatures out there in the world for whom upside down is right side up. For us humans, an upside down world is a mixed up one. The sooner things are righted, the better. For an animal like a flamingo, the only proper head position is down side up when feeding. This bird spends so much time with its head in reverse pose that the bird’s beak only functions properly when upside down.  Sloths spend their entire life upside down – only making things right when descending the home tree to take care of bathroom needs (yes, when it “goes,” it does it right side up).

  Since only plastic flamingoes and zoo-enclosed sloths inhabit our neck of the woods, we need to look to the aquatic realm to find a resident topsy turvy beast, the Backswimmer.  This is one of those insects that are perfectly named.  It carries on most of the functions of life while belly side up. I’d like you study a few of these Backswimmer shots to see what I mean (see here and here

  Backswimmers are insects that are members of the True Bug group.  True Bugs are not the opposite of Fake Bugs, but rather insects that are typified by leathery half wings and piercing moth parts. Assassin Bugs, Stink bugs and the infamous Box Elder Bugs are land lubbing representatives of this group. Backswimmers share the water world with other “bugs” such as the Giant Water Bug, Water Scorpion, and the interestingly named Ferocious Water Bug.  Because most of the aquatic “bugs” are predators, they can inflict painful bites if mishandled. To go along with the tough street names given it’s fellow waterbugs, the Backswimmer is also known as a “Water Wasp” on the lower east side.

  There are many different kinds of Backswimmers out there.  I think the one that sat for my portrait session is a Buenoa margaritacea, but not entirely sure.  Many of these creatures don’t have cute little common names, so we need to talk about them as a group rather than as individuals.  A cute little name can be derived by looking into the scientific name. In this case, margaritacea means “pearl like” and Buenoa means “good or beautiful,” so we have the Beautiful Pearl Backswimmer.

  As an insect, the Pearly backswimmer has six legs, but only two are immediately obvious. Superbly adapted for swimming, the last pair of legs is equipped like a set of oars – with the paddle end made up of stiff bristles. The middle pair are fairly short and used for grasping vegetation, while the front legs are bent into gaff hooks to snare prey. Once the prey is pursued and pounced upon, the water wasp impales it with a hollow stiletto beak and proceeds to pump out all its nutritious life fluids. Like disposing an empty box drink carton, the shell of the victim is discarded when the drink is done.

  This species exhibits another interesting upside-down trait through a feature called reverse counter coloration.  Most animals of the air and water are subject to attack from predators lurking below or above them.  To make themselves harder to locate, such critters are normally dark colored on top and light colored below. In this way, they are more difficult to see against the lighter sky above, when viewed from below, and equally as hard to see against the darker background when viewed from above. This is called counter coloration.  Being a reverse kind of dude, the Backswimmer is therefore light colored above (nearly white, as a matter of fact) and dark colored below. Neat, eh? 

    Like other aquatic insects, the Pearly Backswimmer takes along a bubble of air in order to breathe underwater. Patches of bristles on the abdomen trap and hold a silvery blanket bubble during dives.  When at the surface, the Backswimmer suspends itself – up side down of course – and projects the tip of his abdomen into the air in order to replenish the oxygen supply. Our pearly friend breathes through tiny breathing pores on the abdomen that open into the trapped air.  According to one reference, the water wasp can remain underwater for up to 6 hours if inactive.  They are rarely in an inactive state, however, so they are constantly diving and rising in their quest for life.

  Part of that life quest involves locating a mate, and male backswimmers are known as accomplished serenaders.  The males rub their front legs along a “stridualatory” structure on their chest to beat out a romantic melody that is irresistible to female backswimmers (I do not believe that this song contains a secret message if played right side up, either). 

  Should no females answer the call, the water wasp has one more backhanded trick to perform – it can fly to another pond (or to your pool).  As far as I know, Backswimmers yield to the laws of aerodynamics and fly right side up.

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