Answer:
Mormon cricket, which is actually a shield backed katydid (long-horned grasshopper) is called a Thief. That’s because this cricket feeds on grazing lands in the western United States, especially cultivated crops such as alfalfa and vegetables. Grasses and shrubs such as sagebrush are also eaten. A swarm of these insects can wipe of a farm of its crops. The farmers have thus nicknamed this particular grasshopper as a 'Thief'.
Animal : Grasshopper
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