THIS SPECIES ORIGINATES FROM NORTH AFRICA AND IT HAS BEEN SUGGESTED THAT THE URGE TO MIGRATE IS TRIGGERED WHEN AN INDIVIDUAL ENCOUNTERS A CERTAIN DENSITY OF ITS OWN KIND WITHIN A GIVEN AREA. THIS THEORY MAKES PERFECT SENSE SINCE THIS SPECIES CAN OCCUR IN HIGH DENSITIES THAT RESULT IN FOODPLANTS BEING STRIPPED BARE ON OCCASION WITH MANY LARVAE PERISHING AS A RESULT.
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