Which statement about Anopheles quadrimaculatus is true?

• A. Main U.S. malaria vector east of the Rockies.
• B. Overwinters as fertilized female in trees and basements.
• C. Eggs laid in rafts on water surface.
• D. Larvae inhabit fast-flowing streams only.

Answer: (A)

This question focuses on identifying the primary malaria vector in the United States east of the Rockies. Anopheles quadrimaculatus has historically been the main malaria vector in that region, which is why the statement about it being the principal U.S. malaria vector east of the Rockies is true.

Understanding the Mosquito biology helps here: malaria transmission is linked to Anopheles mosquitoes, and this species has long been associated with eastern U.S. malaria risk because it breeds in clean, sunlit, standing or slow-moving waters such as ponds, marsh edges, and similar habitats. Its eggs are laid singly on the water surface rather than in rafts, and larvae develop in these quiet, clean water bodies rather than exclusively in fast-flowing streams. Overwintering strategies can vary among mosquitoes, and being described as a fertilized female overwintering in trees or basements isn’t a defining trait of this species. The option describing eggs laid in rafts and the one limiting larvae to fast-flowing streams do not fit Anopheles quadrimaculatus.