Our mosquito story is a climate story. In the Early Holocene around 8200 years ago, the area that is today the Sahara Desert was much wetter and supported grassland vegetation. During the mid-Holocene, about 5000 years ago, changes in the monsoon began to dry out much of north Africa. This caused the Sahara to expand, and the yellow fever mosquito (Aedes aegypti) was forced to retreat to areas where they could still find standing water to breed. These were also the same places where humans migrated, congregated and settled. A changing climate brought people and mosquitoes together, and the yellow fever mosquito adapted by preferentially biting humans instead of other animals for their blood meal. They also adopted human-manufactured containers as a preferred breeding site over the natural tree holes that had been their breeding habitat in the past.
Today, changes in climate are creating new habitats for mosquitoes far outside the range they occupied a hundred years ago. Mosquito observations by citizen scientists using the GO Mosquito Habitat Mapper will help us track certain mosquitoes-such as the yellow fever mosquito- as its range expands north in the northern hemisphere, and south in the southern hemisphere.
With the expansion of vector mosquitoes comes also transmission of diseases into new areas. But that is not the only impact of a warming climate. We also know that certain arboviruses (viruses carried by insects) have higher rates of transmission in warmer temperatures. The viral particles spread more rapidly in the mosquito when the ambient temperature is higher. At higher temperatures, mosquitoes become more effective vectors of disease!
For those who would like more information about mosquito biology and the transmission of disease, I highly recommend a video that was released last week by our colleagues at FIOCRUZ, a research institution in Rio de Janeiro, Brazil that is renowned worldwide for its contributions to our understanding of public health. The documentary includes both real HD and 3D virtual modeling and animation images that will help you understand the morphology and behavior of the species of Aedes mosquitoes that transmit pathogens that can cause disease. The video also clearly describes how a viral infection in a mosquito interacts with the mosquito’s physiology and renders them capable of transmitting viruses to new hosts.
There have been some requests for information on basic mosquito biology in this group, and I would like to hear your comments on the video and if you think you could use clips of it in your classroom- please tell me what you think. You can put your comments in the "ask a scientist" thread. The video is available in English, Spanish and Portuguese.
Knowing the mosquitos of Aedes - Transmitters of arboviruses https://youtu.be/lnIEvefMW5Y
Conociendo los mosquitos Aedes - Transmisores de arbovirus https://youtu.be/jpNFe3l2h3A
Conhecendo os mosquitos Aedes - Transmissores de arbovírus https://youtu.be/3tiuRHuzST4