Houston's warm weather and high humidity mean it's a perfect breeding ground for mosquitos, and species that originally inhabited tropical, sub-tropical, and temperate climate zones can all make comfortable homes in the city. There are 85 known species of mosquito in Texas. But Houston is home to both a major port and one of the world's busiest international airports, meaning that the introduction of new species of mosquitos and new diseases for mosquitos to carry are always a threat.
Mosquitos are a essentially a year-round pest in Houston, only disappearing in the cooler parts of January and early February. Mosquito infestations in the city will go through yearly cycles, the intensity of the mosquitos in any given year usually depending upon the amount of rain in the spring and early summer. Mosquitos need standing water to lay their eggs, so more rain will mean more water and more mosquitos.
Like many insects, mosquitos have a complex life cycle. Understanding the mosquito life cycle can help you understand how to control mosquitos around your home.
Water is an essential part of a mosquito's ability to reproduce. Mosquito eggs need to be floating on water to hatch. Most mosquitos will lay their eggs in any available standing water. However, some species, including species found in Houston, will lay their eggs in damp soil and these eggs will lay dormant until the area floods. While most mosquito eggs will hatch into a larvae a few days after they are laid, dormant eggs can remain viable for several years and can withstand severe drought and sub-zero temperatures. That's why a year of drought followed by a year of rain usually means a bad mosquito season in Houston. Then, not only are this year's eggs hatching, but so were all the eggs that lay dormant in the previous year's drought.
Once the eggs hatch, they become larvae. In this stage of its life, the mosquito is small and worm-like and lives floating near the surface of the water, feeding on passing organic matter and breathing through a tube it extends to the surface. Mosquito larvae are visible to the naked eye, and appear as small, transparent squiggles floating at the top of stagnant water. The mosquito will remain in this state for several days, before sinking to a safe place below the surface of the water and forming a hard cocoon. This is the third stage of its life, the pupal state.
Once inside the cocoon, the mosquito's body transforms into its new form, and after several days the adult mosquito rises to the surface of the water. After its body hardens and its wings dry, the mosquito takes flight and after several days will begin to seek out blood to feed upon. Once fed, mosquitos will mate. Although most mosquitos have a short life cycle and will only live several weeks, they can mate multiple times during their life, and each female mosquito can lay as many as 200 eggs at a time. Some estimates say that at the height of the breeding season, an area in a suitable climate can contain over one million mosquito eggs per acre.
The chief threat posed by mosquitos is their ability to spread disease. In Houston, West Nile Virus and St. Louis encephalitis have both been known to be spread by mosquitos for some time. Both of these diseases are series and potentially life-threatening. Both diseases can begin with symptoms such as fever, headache, dizziness, and weakness.
More recently, a new species of mosquito, Asian tiger mosquitos, have begun to be established in Houston. Asian tiger mosquitos spread chikungunya virus, a debilitating disease that can cause severe joint swelling and pain.
Controlling mosquitos can be a challenge. Keeping standing water from around your home is an important step, including making sure that all gutters are kept clean and that birdbath water is changed regularly. Wearing an effective mosquito repellent can help prevent being bitten, but eliminating the eggs and larval forms of mosquitos is an important part of reducing the entire population. Methods such as mosquito barrier fogging can help reduce overall mosquito populations around your home.