Curious behavior

On a walk the other day I noticed several adult female grasshoppers on the edge of the asphalt walking path, probing the ground with the tips of their abdomens.

female two-striped grasshopper

This is mostly likely the common Two-striped Grasshopper, displaying some curious behavior as it spun around in a circle in front of me.  At intervals it touched the tip of its abdomen to the surface, poked up and down, and then continued to move around in a circle.

female two-striped grasshopper abdomen

A closer look showed that this was indeed a female grasshopper. Those shovel-shaped plates that make up her ovipositor at the tip of her abdomen dig into soft soil to create a long burrow in which she will lay her eggs.  Males, in contrast, have a blunt-ending abdomen.

A summer of eating and growing from the very tiny nymph that hatched last spring has matured this female into an egg-laying machine this fall.  She might be testing to see what lies under this rocky substrate, but a soft sandy soil would be the best type of soil for her egg-laying efforts.

female two-striped grasshopper abdomen-closeup

Those sturdy looking appendages at the tip of her abdomen are keratinzed plates that are moved by the actions of 10 sets of muscles in the two terminal segments of her abdomen.

Sets of opposing muscles open or close the plates together, protrude or retract the ovipositor, as well as moving it side to side and up and down.  As the ovipositor enters the soil, it opens, pushes soil to one side of the hole, and gradually lengthens to expand the depth of the hole.  Continued maneuvers of the ovipositor deepen the hole until it is sufficient for the egg mass she plans to leave there.

female grasshopper laying eggs in burrow-Thompson 1986

Who knew that a female grasshopper could extend its abdomen 3-4 times the length of its relaxed body length? But that is only part of what is amazing about this grasshopper’s reproduction. Apparently, the nerve control for this entire operation rests in a terminal nerve ganglion, not in the grasshopper’s small brain. This means even a beheaded grasshopper can still finish laying its eggs.

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