Mosquito larvae move in water, earning them the common names “wigglers” or “wrigglers.” This aquatic stage is a necessary part of the mosquito life cycle, which begins when a female lays eggs in or near standing water. Larvae spend approximately four to fourteen days in the water, depending on the temperature, where they feed and grow before transitioning to the pupal stage.
How Larvae Propel Themselves
The characteristic movement of the mosquito larva is a rapid, jerky motion resulting from the contraction of its segmented abdominal muscles. Unlike many other aquatic insects, the larva does not possess specialized appendages for swimming. It propels itself by vigorously twisting and contorting its entire body in a thrashing manner.
This locomotion is primarily a defensive action, allowing the larva to quickly dive away from the water’s surface. Larvae are highly sensitive to disturbances, such as shadows cast by potential predators or vibrations in the water. The downward, wriggling dive offers immediate protection, after which they slowly float back up to the surface when the threat has passed.
The Role of the Siphon in Movement
Larval movement is linked to the need for atmospheric oxygen, which is collected through a structure called the siphon. This tube-like organ is located at the posterior end of the abdomen and functions like a snorkel, piercing the water’s surface tension to take in air. When the larva is at rest, it hangs suspended upside down just below the surface, with only the tip of the siphon breaking through.
The siphon allows the larva to anchor itself to the surface film for respiration. When the larva executes its defensive, downward movement, it must detach from this surface anchor to dive into the water column. Specialized species, such as those in the Coquillettidia genus, can pierce aquatic plant stems to draw oxygen directly, eliminating the need to rise to the surface.
Where Mosquito Larvae Are Found
Mosquito larvae are found in any body of standing water that remains undisturbed for a minimum of about four days. This includes a wide range of habitats, from large, permanent water sources like ponds and marshes, to temporary floodwater pools and drainage ditches. However, the public is most likely to encounter them in artificial, human-made containers.
These small, translucent larvae are frequently found in neglected items such as bird baths, flowerpot trays, old tires, and clogged rain gutters. The presence of these “wigglers” is a clear sign of a mosquito breeding site.