By: Michael Mut, Miami-Dade County Public Information Officer
As a species, mosquitoes haven’t changed much in 46 million years. There is fossil evidence documenting the existence of a creature very similar to the modern day pests dating back to the Cretaceous Period, or 79 million years ago. Some studies date them as far back as 210 million years. They are widely regarded as the most deadly animals on planet Earth, killing more than 1 million people per year (according to World Health Organization estimates), mostly in Africa and by transmitting malaria.
So what can we attribute their long-lasting existence to? Some point to their short, efficient life cycle. Going from egg to full-blown, bloodthirsty adult in as little as four days, there always seem to be winged reinforcements coming. This is especially true in an area such as Miami-Dade County, which up until about 100 years ago was largely wild and untamed Everglades swampland.
Mosquitoes go through four separate stages during their short, happy lives: egg, larva, pupa and adult. Depending on the species, females lay single eggs or multiple clutches, which are bound together and called rafts. Most are laid on or very near to standing water; at least two known species spawn on damp soil likely to be covered by water. The majority hatch within a couple of days, but eggs are affected by extreme heat, which can prevent them from hatching.
Mosquito larvae live in the water, frantically wiggling about and coming to the surface to breathe through siphon tubes. Some species attach themselves to plant matter and get their oxygen there. They mostly survive on microscopic organisms and organic matter, and shed their skin four times, getting larger with each molt.
The pupa stage is similar to the cocoon stage seen in butterflies, and is characterized by rest and non-feeding. This critical phase is one where the mosquito transforms into an adult. Pupae remain mobile, quickly moving by flipping their tails. Once ready to emerge, the pupa rises to the surface and its skin splits.
Adult mosquitoes emerge from their pupal chrysalis and rest on the surface of the water until all body parts have dried and hardened. When ready, the youngling spreads its wings and takes flight. Within a couple of days, the mosquito begins to seek out mates and blood victims, and lives for up to a month.
There are more than 45 species of mosquitoes found in Miami-Dade County, but we are most concerned with three types: Aedes aegypti (the infamous carriers of Yellow Fever and the Zika virus), Aedes albopictus (the Asian Tiger mosquito) and the Aedes taeniorhynchus (the Salt Marsh mosquito).
Here are some fast facts about adults:
- Only females bite
- Mosquitoes do not have teeth, but instead pierce skin with a serrated tube-like “proboscis”
- Both males and females feed on fruit and nectar
- A female can drink up to three times its weight in blood
- Females lay up to 300 eggs at a time
- The Aedes aegypti and Aedes albopictus mosquitoes can’t fly far (up to a city block), fast (1.5 miles per hour) or high (about 25 feet)
- The Aedes taeniorynchus mosquitoes are fierce biters, attack any time of day but are especially active during the dark hours, and can travel 20-40 miles when assisted by wind speed and direction
- Females find their prey by smelling the CO2 in their breath, tracking body heat and by detecting the octanol, cholesterol, and folic acid emanating from skin
- Dark clothing retains heat, thus attracting mosquitoes
- Fish and dragonflies are the mosquito’s main predators
Miami-Dade County’s Mosquito Control and Habitat Management Division, a part of the Solid Waste Management Department, uses the most effective methods, techniques, equipment and products to control the area’s mosquito population. Through a year-round Integrated Vector Management program of surveillance, site inspections, manual, truck and aerial spraying, as well as community education and outreach efforts, Mosquito Control works to enhance the quality of life for residents and visitors and to reduce the transmission of mosquito-borne illnesses.
For more information about how you can Fight the Bite and learn more ways to Drain & Cover, please visit www.miamidade.gov/mosquito or call 311.
Above content provided by Miami-Dade County.