Typically considered a nuisance, mosquitoes are tiny insects that are known vectors of various diseases harmful to both humans and animals. Normally consumers of nectar, female mosquitoes also feed on the blood of other animals, including humans. Blood feeding is needed for egg production. There are about 74 species of mosquitoes in Canada of which about 60 are known to bite humans and other animals. The most troublesome pest species are the Aedes species which exist across the country.
Appearance / Identification
What do mosquitoes look like?
Adult mosquitoes like other insects have three body parts: head, thorax, and abdomen. Three pairs of long legs, a pair of membranous, scaled wings, and halteres are attached to the thorax. The shape, pattern, and colour of the wing scales vary depending on species; in some species, the wings are brilliantly coloured and patterned. The body is typically slender with long legs, ranging in size from 4 to 10 mm in length. The head has a beak used for feeding, which in females is modified into a needle-like structure called a stylet used to pierce and suck blood from hosts. Male mosquitoes have long, feathery antennae, while female antennae are slightly hairy.
Mosquitoes typically breed in still water, as running water such as streams wash out eggs, larvae, and pupae. Examples of ideal habitats include storm sewers, flooded areas, tree holes, old tires, bird baths, flower pots, and anywhere water may accumulate for more than three days. Adults rest in tall, shady vegetation near a water source or in other protective resting areas whenever not in search of hosts to feed on. Mosquitoes tend to be more active under sufficient cloud cover or in shady areas compared to locations in direct sunlight.
What do mosquitoes eat?
Both sexes of all mosquito species feed on sugar sources, which include plant nectar, honeydew, fruit juice, and other plant secretions. However, the females also need blood for egg production; therefore, it is only the females that bite and feed on blood. Mosquitoes are less specific in their host preference. Host preference depends on the mosquito species, availability of host, and the environment; it ranges from mammals and birds to reptiles and amphibians. Most species in the arctic feed on warm-blooded animals. Larvae feed on various dead and living micro-organisms in the aquatic environments they live in, including algae, bacteria, fungi, and even flotsam.
Predators: What Eats Mosquitoes?
While little scientific proof exists to confirm that predatory fish, birds, and bats provide effective mosquito control, these predators are known to consume adult mosquitoes and larvae in varying amounts depending on availability and dieting preferences. The Western mosquitofish, or Gambusia affinis, ingests considerable amount of mosquito larvae; however, the fish is found mostly in warmer climates and occurs only in Ontario and Alberta in small numbers. While purple martins and bats are mostly opportunistic feeders of mosquitoes, mosquitoes remain a small percentage of their diets. Relying on bats to provide noteworthy mosquito control may prove futile. Because bats are opportunistic feeders, mosquitoes are not their primary food source. The flying mammals feed on other things, too.
Life Cycle & Reproduction
Mosquitoes undergo complete metamorphosis with four distinct stages: eggs, larvae, pupae, and adults. The larva is the second developmental stage. Mosquitoes lay eggs either singly or in multiples, called egg rafts, either directly in the water or near a source of water. Eggs hatch in one of two cycles: direct-hatching or delayed-hatching. Direct-hatching eggs are laid directly on top of shallow standing water, and the eggs hatch in a matter of two to three days. Delayed-hatching eggs are laid on moist substrates, and they go through a necessary dry period of several days or weeks and then hatch once submerged by water.
Eggs are laid either singly or in clusters on the surface of stagnant water. The eggs hatch into tiny worm-like larvae also known as wrigglers, because they move by wriggling in the water. The larvae go through four instars before becoming pupae, and this stage lasts on average for seven days. Mosquito larvae can grow up to 15 mm long and feed on a diet of algae and other organic matter in the water. Unlike adult mosquitoes, larvae are exclusively aquatic and have the ability to live in any space capable of retaining water for several days. In addition to ponds and flooded areas, rain barrels and bird baths make ideal habitats for mosquito larvae.
Problems Caused by Mosquitoes
Most mosquitoes found in Canada are more of a nuisance than vectors of disease, though a few species are known vectors. The constant buzzing and flying around can be annoying, and they can inflict very painful, irritating, and distracting bites, which can disrupt outdoor activities. The biting and nagging can also cause misery to livestock with some economic implications. As natural vectors of certain pathogens, mosquitoes transmit pathogens and parasites that cause certain diseases. Some of the most common known pathogens include plasmodium that causes malaria, West Nile virus, encephalitis viruses complex, and filarial heartworm in dogs.
Signs of Infestation
The most common signs of mosquito infestation is the buzzing sound the female mosquito makes in flight, followed by bites, and also by seeing adults resting on walls, vegetation, or similar resting sites during daytime. Another common sign is the presence of the larvae – wrigglers in stagnant water, which often seem attached to vegetation or objects in the water. When disturbed, they dive under the water. Together with the wrigglers are the “comma-shaped pupae,” the tumblers. The presence of these immature stages show active breeding.
The most common way to prevent mosquito infestations is to eliminate breeding sites. Inspect backyards or property for potential breeding sites. Any container that can hold water for more than three days should be removed. If the container cannot be removed, such as bird baths or decorative pots, drain them of water at least weekly. This will cut off the development cycle. Level up or fill redundant ditches or holes. Keep ponds and fountains clear of weeds or vegetation, and allow frequent water flow or mixing to prevent egg laying and development. Maintain well-trimmed and managed vegetation to eliminate resting sites for the adults. On large scales, local communities may ditch, dike, and manipulate water management as well as retrofit storm drains and catch basins. When being outdoors, the use of personal protection, such as insect repellants and wearing long sleeves and light-colour clothes, will help to reduce biting. In case of a large and widespread infestation, consult a licensed pest control professional.
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