Maryland Pesticide Applicator Category 8: Public Health (Mosquito Control) Practice Test

Most mosquito larvae stay submerged in water but must access air. They have a snorkel-like siphon that projects from the last abdominal segment up to the surface, allowing them to draw air into their tracheal system without fully leaving the water. This provides a steady supply of oxygen from the air, which gills or diffusion through the cuticle alone can’t efficiently deliver in their aquatic environment. Breathing through spiracles at the abdomen isn’t the typical setup for their larvae, and diffusion through the cuticle would be too slow to meet their needs. So the siphon tube near the last abdominal segment is the key feature that enables their underwater breathing.