When Are Mosquitoes Most Active?
Mosquito Behavior & Activity
Mosquito activity depends upon a number of factors, some of which are described below. We’ll begin at the most basic, obvious signs of mosquito activity and progressively introduce other indicators, which may not be so easily recognized.
There are more than 3,000 species of mosquitoes worldwide, so it is very difficult to accurately describe the behavioral differences of many of these species.
Therefore, within some very specific and distinct mosquitoes groups, behaviors and activities may be fairly unlike the general mosquito behaviors reported here.
Within North America, general mosquito activity generally increases from south to north and from coastal to inland habitats simply because the diversity and the size of mosquito populations increase, as well.
While certainly not always the case, the likelihood of observing mosquitoes actively flying or taking a blood meal is greater in the southern states and those specific habitats that are close to large bodies of waters.
Meteorological Conditions Affecting Activity
Conditions that affect mosquito activity are:
- Wind: Mild, little or no wind since mosquitoes generally are not strong flyers.
- Temperature: Low temperatures that may reduce, suspend or entirely prevent adult flight activity, plus excessively high temperatures that also retard flight activity. Warm temperatures of approximately 80° F are very favorable to most species of mosquitoes.
- Humidity: Relative humidity is important to mosquito activity. In general, high humidity conditions favor mosquito activity, while low humidity suppresses activity and may even cause mortality.
- Precipitation: Rainfall, if heavy enough may injure flying, exposed mosquitoes and force them to seek shelter, thus preventing flight.
- Drought & Rainfall: Both drought and above normal rainfall conditions can considerably affect suitable breeding sites for mosquito development.
For example, a sustained, long drawn out drought will evaporate the surface water from a wetland and temporarily halt mosquito larval production. A mosquito development season with frequent rainfall will maintain a higher water level, which usually favors development of mosquitoes.
Activity During a Mosquito Swarm
It is not uncommon for hundreds or perhaps even thousands or more of new male and female adults to be seen actively flying in a swarm. One of the most important activities taking place in the swarm is copulation with and insemination of the females by the males.
In fact, these behavioral necessities for mosquito reproduction usually occur while the mosquito “couple” is airborne. Mosquito experts have researched this behavior and discovered that sound and wing beat frequencies produced by the males and females are at least one of the various phenomenon that serve to attract them to each other.
Unlike male mosquitoes, which will continue to mate until they die, most female mosquitoes will mate just once and will store the male’s sperm to fertilize all eggs she produces for the remainder of her life.
After completing its pupal stage and developing into an adult mosquito, one of the first things the adult does is seek out a place that is dry, shaded and protected from wind so they can finish their transition from being an aquatic organism to becoming a terrestrial creature.
Once the new adult mosquito has completed this transitional process, they are ready to take wing and begin searching for food to energize their activity. However, one may be surprised to learn their first meal usually consumed by mosquito adults is sugary, energy yielding meals provided by plant nectar.
At this new stage of their lives, both males and females search for nectar, foods that will energize the male and female each time they feed on plant nectars for the remainder of their life.
But wait, I thought females fed on blood. While that is obviously true, most species of female mosquitoes require blood feeding, which primarily enables them to lay viable eggs that hatch and thus begin the life cycle of a new generation of mosquitoes.
Once her egg laying is done, she will again search for nectar and won’t take another blood meal until she is ready to deposit subsequent batches of eggs.
Blood feeding activities of the females vary between species and habitat location. Those mosquitoes occurring in the northern regions of the U.S. and Canada that have perhaps only one or a very few generations per year, feed in huge swarms containing so many blood feeding females that hosts can become anemic or may even die as the result of blood loss.
Some mosquito females are general feeders, while others feed only on specific groups of vertebrates such as birds or reptiles. Their flight habits are also variable, some species flying no more than several hundred feet from their breeding sites and others flying several miles or more.
Flight Activity While Seeking Suitable Egg Laying Sites
In general, warm, humid and windless conditions favor the gravid (pregnant) female’s search for places to deposit eggs. Studies using mosquito traps showed that catches of gravid mosquitoes decreased when wind speed went up.
Also, low temperatures, low ground moisture, low relative humidity and low light intensity may affect the flight and egg laying behavior of many mosquito species. In addition, those female mosquitoes that are normally active at night will lay eggs at dusk, early nightfall and during moonlit nights.
This behavior is thought to be the result of water at egg laying sites reflecting both natural and artificial sources of light, thus making these sites more visible to gravid mosquito females.