Friday, March 10, 2017

The case of the green and brown grasshoppers - are they the same or different species?

Dr Abe V Rotor
Short horned grasshopper (Oxya velox).  Photo credit, Wikipedia

The old folks tell children they are one and same. The grasshopper is like the chameleon. They can change colors to mimic their environment.  It is a way of defense and offense - to escape their enemies and catch their unwary preys. Here are other examples to illustrate this biological phenomenon.

  • ·         Moths near industrial sites are darker than their counterparts in the countryside, mimicking the bark of trees and walls of buildings darkened by carbon dust.

  • ·         The octopus is a master mimicker; it does not only change colors but patterns as well, sometimes assuming the likeness of other sea creatures, or a piece of coral or simply a colored landscape.

  • ·         Nonpoisonous butterfly species resemble the poisonous species to escape predation. Examples are the nonpoisonous Viceroy butterfly (Limenitis archippus) resembles the poisonous Monarch butterfly (Danaus plexippus). Both are  identical that birds have learned to avoid eating both of them.  

  •  ·         The leaf-footed preying mantis is perfectly hidden among leaves; the walking stick looks like a piece of twig; the bagworm could be mistaken for a thorn.    
Going back to the puzzle of the grasshopper, in summer it is brown; during the rainy season, it is green.  As an entomologist I have observed the various coloration and patterns of short-horned grasshopper (Oxya velox) with the change of seasons. I would tell my students, just like the old folks telling me when I was a kid, “They are one and same.”   

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