Sunday, August 12, 2012

Cooperative Grasshopper

I chase a lot of grasshoppers around the prairies in hopes of getting some quality photos of these fascinating creatures.  The process usually involves slow crawls through the tall grasses.  When I do get close enough to take pictures, it’s almost impossible to get side shots without blades of grass getting in the way.  While I was walking past the garden, I scared up a Coral-winged Grasshopper, Pardalophora apiculata, that was obliging enough to land on the horizontal brace timber of the fence corner.

The Coral-winged Grasshopper and the look-alike Orange-winged Grasshopper are commonly seen on the prairie.  Their pinkish red hind wings are highly visible while they are in flight.  Upon landing, they easily blend into the surrounding ground cover.  The visible difference between the two is found on the inside surface of the hind femur.  Orange-winged shows bright blue in this area and Coral-winged is without blue.  This area is usually hidden from view, but is often exposed as the grasshopper walks.

One of the distinguishing features of this grasshopper is the V formed by light bands running the length of the forewings.  The V is so prominent that it is the first thing you notice about this animal.

The grasshopper form has some remarkable features.  One of my favorites is the pronotum, a tough shield-like affair that sits like a saddle atop the thorax.  It makes the grasshopper appear as though it is dressed for battle.  I’ve watched mantids gnaw futilely against the pronotum in an attempt to feast upon the grasshopper.  Of course, all the mantid had to do was adjust its grip and attack a vulnerable spot, so the pronotum never actually saved the grasshopper.

The workings of the hind leg have always impressed me.  In order to jump, the tibia acts as a lever with the fulcrum, or pivot point, being in the large joint at the meeting of the two leg segments.  When we use levers, we apply a small force on the long end of the lever in order create a large force on the small end.  The grasshopper leg works in the opposite way.  A great amount of force must be applied to the short segment of lever in the joint in order to produce enough force in the long segment to propel the grasshopper’s body into the air.  The force of the jump may only be five or ten percent of that applied in the joint.  That inefficiency of transfer makes a long distance jump even more amazing.

4 comments:

  1. Fascinating. It all reminds me of catching them when we were kids, then trying to get the "stuff" off of our fingers. It surely served us right for bothering them. ;)

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  2. Hi Lois. I know what you mean. I spent a lot of time catching those "tobacco chewers."

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  3. They really do look like they're wearing armor. Nice detail shots of this little creature.

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