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Skip to 0 minutes and 11 seconds In this step we will ask where do you find Aedes aegypti larvae. The ancestors of Aedes aegypti almost certainly lived in Sub-Saharan Africa. The larval habitat of these insects was likely natural container such as tree holes and adults would have fed primarily on wild animals. While this ancestral form still exists in forests and vegetated environments of Africa today, in most parts of the world Aedes aegypti is almost completely domestic, living in close association with humans.

Skip to 0 minutes and 40 seconds This domesticated Aedes aegypti arrived in the new world soon after the first Europeans. The ability of their eggs to survive desiccation and their larvae to resist starvation for several weeks at a time means that they could have travelled on trade ships sailing between Europe and the Americas. It is not known whether the domestication took place before or simultaneously with this introduction to the Americas, but the breeding habitats of the domestic form have been altered considerably. Today, larvae will commonly be found in artificial containers provided by humans. They will even breed indoors, and of course they have a preference for feeding on human blood.

Skip to 1 minute and 15 seconds In the 1950s, concerns about the spread of yellow fever in Malaysia prompted regular surveying of airports and seaports. Surveys were also conducted in the urban areas. The most common habitats to find larvae in were tyres, buckets, flowerpots, and other assorted pots, pans, cups, and jugs, both indoors and outside. While the collections did not extend to more rural areas, it was clear that Aedes aegypti found artificial containers filled with small bodies of freshwater to be suitable for laying their eggs. It’s likely that the female has found these places extremely convenient to deposit her eggs in, as these containers are frequent features in many households.

Skip to 1 minute and 57 seconds A more recent survey of larval habitats in an urban area of Costa Rica with a history of mosquito control supports the earlier findings from Malaysia. Here again, tyres were most commonly found with larvae and followed by gutters, drums, and other containers. In Ethiopia, 750 artificial containers were collected from an urban environment and 54% had mosquito larvae in them. As with previous studies, larvae were found in a range of man-made habitats. The indoor and larger containers may provide a perennial water source for mosquitoes, while many outdoor containers, particularly where seasons are sharply defined, represent only temporary breeding sites.

Skip to 2 minutes and 36 seconds It is not known exactly how a female selects the site to lay her eggs but it is understood that she uses cues of sight, smell, and touch, and will be influenced by different environmental factors such as temperature, rainfall, humidity, and wind speed. It’s important to remember the Aedes do not look after their brood, so selection of a suitable breeding site is a vital part of the female’s role in the life cycle.

Skip to 3 minutes and 1 second So finally, breeding habitat is one of the most critical factors for the survival and population dynamics of Aedes aegypti. The ability to breed in containers around human habitations is no doubt one of the factors contributing to the success of this species and has crucial implications for the control of Zika and other diseases.

Where do you find Aedes larvae?

We now know that Aedes aegypti and Aedes albopictus are present in many parts of the world, and that changes in their distribution have been driven by human activity.

In this step we consider where you might find Ae. aegypti larvae and how the species became domesticated through our influence on the natural environment.

In the last few steps we have been given a number of examples of man-made containers that act as breeding sites for mosquitoes. Think about your own home: where might be a suitable place for a female mosquito to lay her eggs? How many of these places might there be, both inside and outside your home?

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Preventing the Zika Virus: Understanding and Controlling the Aedes Mosquito

London School of Hygiene & Tropical Medicine

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