8/18/2019 CDC - Mosquito Life-cycle - Dengue

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4/3/2016 CDC - Mosquito life-cycle - Dengue

http://www.cdc.gov/dengue/entomologyEcology/m_lifecycle.html

Mosquito Life-Cycle

 Aedes aegypti  and other mosquitoes have a complex life-cycle with dramatic changes in shape,

function, and habitat. Female mosquitoes lay their eggs on the inner, wet walls of containers with water. Larvae hatch (picture 1 , inset) when water inundates the eggs as a result of rains or theaddition of water by people. In the following days, the larvae (picture 2) will feed onmicroorganisms and particulate organic matter, shedding their skins three times to be able togrow from first to fourth instars. When the larva has acquired enough energy and size and is in thfourth instar, metamorphosis is triggered, changing the larva into a pupa (picture 3). Pupae do nofeed; they just change in form until the body of the adult, flying mosquito is formed. Then, thenewly formed adult emerges from the water after breaking the pupal skin (picture 4, inset). Theentire life cycle lasts 8-10 days at room temperature, depending on the level of feeding. Thus,there is an aquatic phase (larvae, pupae) and a terrestrial phase (eggs, adults) in the Ae. aegypti life-cycle.

It is this life-cycle complexity that makes it rather difficult to understand where the mosquitoescome from. Similar complex life-cycles with aquatic and terrestrial forms are observed inamphibians. For educational and training purposes, it is rather useful to make life-cycle kits(http://www.cdc.gov/Dengue/images/Aegypti_Stages.jpg) , so people have an opportunity to watch howthe aquatic stages turn into terrestrial ones.

There is a v ery important adaptation of dengue vectors that makes controlling their populations adifficult task. Their eggs can withstand desiccation for several months, which means that even if alarvae, pupae, and adults were eliminated at some point in time, repopulation will occur as soon asthe eggs in the containers are flooded with water. Unfortunately, there is no effective way to

http://www.cdc.gov/Dengue/images/Aegypti_Stages.jpghttp://www.cdc.gov/Dengue/images/Aegypti_Stages.jpg

8/18/2019 CDC - Mosquito Life-cycle - Dengue

2/2

4/3/2016 CDC - Mosquito life-cycle - Dengue

http://www.cdc.gov/dengue/entomologyEcology/m_lifecycle.html

Page last rev iewed: September 1 0, 20 09

Page last updated: Septem ber 27 , 201 2

Content source: Cent ers for Disease Contr ol and Prev ention

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control the eggs incontainers.

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