The Assassin Who Came in from the Cold: The Wheel Bug

Wheel bug. J. Schaeffer

A well-equipped  assassin dropped by the nature center recently, and we were happy to see him.   It was a wheel bug, a member of the assassin bug group, and its mouth is its weapon of choice.  Wheel bugs attack and consume a wide  variety of insects, many of which are considered garden, agricultural and forest pests.

Why do we like it?  Let me count the ways:

1.  It's a big bug.  A bug this big (1.5 inches) is noticeable and it's easy to see the three insect characteristics: six legs, three body parts, two antennae.

2.  It looks cool.  The semi-circular, cog-like structure on its back gives it a  bizarre, mechanical look.   In fact, no one is quite sure of the purpose of the "wheel". 

3.  This bug means business.  It has formidable and prominent mouth parts (also called a beak or  proboscis) equipped for piercing and sucking, much like a hypodermic needle or the straw on a juice box. When a suitable prey item comes near, the wheel bug lunges forward, seizes the prey with its front legs and plunges its sharp beak into a soft part of the prey insects' exoskeleton.  It then injects enzymes which paralyze the prey and digest its innards.  Finally, the bug sucks up its liquefied meal, leaving only an empty shell behind.  Be careful handling this critter--its bite has been likened to the sting of a wasp, only ten times more painful.


4.  It eats stink bugs.  We've been looking for a way to eliminate, or at least reduce, the number of the marmorated stink bugs which have invaded the nature center again this fall, and the wheel bug may be part of the answer.  Our new friend devoured two stink bugs in a dramatic (and smelly) predator/prey encounter.   Dr. Mike Raupp, University of Maryland Extension, has an action video of a wheel bug/stink bug contest at his Bug of the Week web site at:  http://www.bugoftheweek.com/BugOfWeek_38F.html#writelink1
                  


Wheel bug vs. stink bug. J. Schaeffer

I think we'll keep our friendly assassin around for a while--should be a wheely good show and wheel certainly have plenty to feed him.  Thanks, Larry, for noticing this armed (mouthed?) intruder.