Floodwater Mosquitoes

Many people associate mosquitoes strictly with standing water, with the belief that mosquitoes must have water to lay their eggs. The fact is, mosquito eggs need water to HATCH – but some species lay their eggs in moist soil (not standing water) and the eggs need to dry out before they can hatch. These mosquitoes are the “floodwater” species. As far back as one year from the time the floodwater mosquitoes are noticable, the adult female mosquitoes were flying around, feeding on blood, and laying eggs (one female floodwater mosquito has the potential to lay 200 eggs per batch) in moist areas of pastures, citrus furrows, salt-marsh, and swales. These moist areas eventually dry out, and the mosquito eggs also dry and become encased in the cracks and crevices of the dried mud. Because of their unique biology, the eggs need to dry out before they could hatch into larvae. The eggs survive in the dry soil through the winter and spring, and then with rains from storms, those areas are inundated with water. The water that reaches the eggs provides a cue to hatch. One can consider the potential extent of this habitat by thinking about how much land in Florida is pasture, citrus grove, or large expanses of uninhabited flat land. There are estimates of the number of mosquito eggs in a floodwater habitat between 0.7 and 1.3 million eggs per acre. Yes – per acre. If only a small percentage of those eggs hatched and survived to the adult stage, the number of adult mosquitoes flying around looking for blood at one time is almost incomprehensible. Unfortunately, for those who are diligent about dumping water and cleaning up containers around their home, this type of local and small scale effort will not contribute much impact to reducing mosquitoes in the floodwater sites. Florida floodwater mosquito species include Culex nigripalpus, Ochlerotatus taeniorhyncus, and Psorophora columbiae.

Florida floodwater mosquito species
Culex nigripalpus Aedes taeniorhyncus Psorophora columbiae

Permanent Water Mosquitoes

Mosquitoes that are not in the “floodwater” group lay their eggs on standing water. A difference between the two groups is that mosquito eggs in this category can not withstand drying out. If the water dries up, or the egg gets stranded on the grass or soil, the egg dries and that will be the end; it will not hatch into a larva. Females will lay their eggs on the water surface and the eggs will typically hatch in about 24 hours. Water is necessary to complete the life cycle, and soon the larva will change into pupa and then emerge into an adult that is hungry for blood. After the newly emerged female mates and finds a blood source, she can start the cycle all over again by laying her eggs on standing water. Florida permanent water  mosquito species include Anopheles quadrimaculatus, Culex quinquefasciatus, and Mansonia dyari.

Florida permanent water  mosquito species
Anopheles quadrimaculatus Culex quinquefasciatus Mansonia dyari