Mosquitoes, vectors of pathogens - Anopheles gambiae, Aedes aegypti, Culex pipiens: life cycles, biting habits, transmitted diseases at MetaPathogen

Please help keeping these websites open for everybody as long as possible

Mosquitoes

Download this page in pdf format (can be old)

Brief facts

There are currently more than 3,000 mosquito species in the world grouped in approximately 39 genera and 135 subgenera.
The word "mosquito" comes from the Spanish or Portugese meaning "little fly" (mosca - fly; -ito - one of most common diminutive suffixes in Spanish). Indeed, mosquitoes are Diptera - the earliest "true" flies.
The oldest known mosquito fossil, preserved in Canadian amber, dates 76-79 million years ago. Because of its very close resemblance to modern mosquitoes, some researchers estimate emergence of mosquitoes as early as 160 to 205 million years ago.
Some most fierce and relentless mosquitoes live in Arctic tundra. They operate only for several weeks of the year but, apparently, are able to bring considerable grief: dead caribou have been found literally sucked dry by swarms of hungry mosquitoes.
Among blood-sucking insects two feeding procedures are found: first when the insect inserts the tip of proboscis with some precision into a blood vessel of the host (vessel feeders or solenophages), and those when it cuts and stabs in a suitable place and feeds on the extravasated blood (pool feeders or telmophages). Mosquitoes belong to the former group. If the mosquito did not prick the vessel on the first try, she will withdraw its proboscis just a little and will probe around through the same hole until she found one.
All mosquitoes share two common traits: only females are blood-feeding in order to lay eggs, and their larvae must develop in the water.
Feeding habits vary widely. For example, infamous New Jersey mosquito Ochlerotatus sollicitans attacks by spiraling down on its victims directly from above, biting the head or upper body. Many mosquitoes will target their targets for considerable distances. Some mosquitoes buzz loudly and bite painfully, others are stealthily quiet, practically weightless and are great anesthesiologists. The list of variations can continue on and on.

A system for the classification of mosquito life cycle types

For mosquito species found in the northeastern United States include the following primary subdivisions:
- Univoltine Aedine,
- Multivoltine Aedine,
- Multivoltine Culex/Anopheles,
- Unique Life Cycle Types (monotypic, or restricted to single species).
Criteria for assighments include:
- where eggs are laid,
- typical larval habitat,
- number of generations per year,
- stage of the life cycle that overwinters.

Mosquito mating behavior

Mating in mosquito is probably of one of most understudied aspects of their life cycle. It recently came to attention with development of sterile insect technique (SIT) as a control measure of mosquitoes, vectors of important human pathogens. SIT is based on the concept of releasing sterilized, but sexually competitive males who will mate with wild females that will lay sterile eggs thus reducing vector populations. Some of most general characteristics of mosquito mating behavior:
- Males are not competent to mate at emergence because terminalia, sexual organs and antennal fibrillae must first mature. Mating activity and insemination success generally peak between 3^rd and 7^th day post emergence.
- Females of majority of species are ready to mate as soon as they emerge from the pupal cases.
- As a rule, female mosquitoes mate before taking a first blood meal, but in several anophelines a large proportion of virgins may blood-feed prior to mating.
- Many culicine species, characteristically mate in swarms, when males aggregate in large numbers, forming nearly-cylindrical swarms of several meters high. Single females fly into the swarm and are detected by their lower wing-beat, and then, depart in copula.