Which of the following statements is true about Red imported fire ants?

The statement about red imported fire ants originating from Brazil in the 1930s is accurate. These ants were first identified in the United States in the 1930s after arriving from South America, particularly through shipping ports. This introduction led to their establishment in the southeastern U.S. and subsequent spread to other regions. Understanding their origin is crucial, as it provides insight into their behavior, ecological impact, and the challenges involved in managing their populations.

Other statements in the question do not hold true. Red imported fire ants are not well established in Nevada; their primary habitats in the U.S. remain more in the South and Southwest. Additionally, they are not known for sweet feeding habits; rather, they are notorious for their aggressive nature and painful stings. They can indeed pose health risks to humans, particularly to those who are allergic to their venom, which is another reason why knowledge about their origin and spread is important for public awareness and safety.