Mosquitoes

With over 3,500 species worldwide (Hawkes), mosquitoes are often seen as blood-sucking pests responsible for spreading disease. While this is partially true, there’s much more to these insects. Mosquitoes play crucial roles as pollinators and as food for numerous animals. Interestingly, only female mosquitoes drink blood, only 6% of all mosquito species bite humans, and a mere 3% transmit diseases (Forest Preserve District Will County, 2021).

Some have proposed eradicating mosquitoes entirely to prevent diseases, but such an approach would be unnecessary and ecologically harmful. Targeting specific disease-carrying species would be a more sustainable solution. In the Amazon Rainforest, three main mosquito genera—Anopheles, Aedes, and Culex—are known to spread diseases to humans.

Anopheles

The Anopheles genus includes about 460 species globally, with 49 species found in the Amazon (Meireles et al., 2022). These mosquitoes are best known for transmitting malaria, a disease responsible for millions of deaths throughout human history. Only 70 Anopheles species can transmit malaria (Scott, 2012). These mosquitoes are nocturnal, making bed netting crucial for prevention.

Deforestation exacerbates the problem by creating more sunlit pools, prime breeding habitats for Anopheles. Human settlements and cattle ranches also provide blood meals for these mosquitoes. The most significant malaria vector in the Amazon is Anopheles darlingi, a species highly adapted to human environments (Conn & Ribolla, 2016).

Aedes

With around 950 species worldwide, Aedes mosquitoes spread diseases such as yellow fever, dengue, Zika, and chikungunya. In the Amazon, three species are of concern: Aedes aegypti, Aedes albopictus, and Aedes scapularis.

Aedes aegypti, originally from West Africa, arrived in the Americas via the transatlantic slave trade (Sokol, 2023). This species specializes in human blood meals and thrives in urban environments, where its larvae develop in small water containers (Ferede et al., 2018). Similarly, Aedes albopictus, a generalist species from Southeast Asia, benefits from cattle ranching and other human activities (Nava & Debboun, 2020).

Culex

Culex mosquitoes include 770 species globally, with Culex quinquefasciatus being the primary vector for filariasis in the Amazon. These nocturnal mosquitoes lay eggs in various water sources, from lakes to artificial containers (CDC, 2024).

Deforestation and Mosquito Populations

Deforestation in the Amazon reduces overall mosquito biodiversity but creates favorable conditions for disease-carrying species. By decreasing predator populations like fish, dragonflies, and frogs and increasing standing water pools and human proximity, deforestation helps mosquitoes like Anopheles darlingi and Aedes aegypti thrive. Fragmented landscapes with sunlit pools and polluted water further aid these vectors.

Ultimately, less rainforest means more disease-carrying mosquitoes and heightened health risks for humans (Tascoff, 2019). Addressing these challenges requires balancing conservation efforts with targeted public health interventions, such as using insecticides, providing bed nets, and controlling standing water.

References:

Hawkes, Frances M. Hopkins, Richard J. Mosquitos the Place of Pest in a Healthy World National Library of Medicine

https://www.ncbi.nlm.nih.gov/books/NBK585164/

(August 9, 2021) The Buzz Five facts about those pesky mosquitos Forest Preserve District Will County

https://www.reconnectwithnature.org/news-events/the-buzz/5-things-mosquitoes/

Scott, Thomas W. Takken, Williem (March 2012) Feeding strategies of anthropophilic mosquitos results in increased risk of pathogen transmission Trends in Parasitology Volume 28 Issue 3 pages 114-121

https://www.sciencedirect.com/science/article/abs/pii/S1471492212000049

Meireles, Anne Caroline Alves. De Silva Lucas Rosendo. Simplicio, Marlon Ferreria. De Lima, Alzemar Alves. Rios, Flavia Geovana Fontineles. De Menezes, Carla Augusta. Fietoza, Luiz Henriqiue Maciel. Juliao, Genimar Reboucas. (September 6, 2022) Anophiline diversity in urban and pre-urban malaria foci: comparison between alternative traps and seasonal effects in a city in the Western Brazilian Amazon Malaria Journal

https://pmc.ncbi.nlm.nih.gov/articles/PMC9450372/#:~:text=Mosquitoes%20of%20the%20Anopheles%20genus,the%20Brazilian%20Legal%20Amazon%

Hinne, Issac A. Attah, Simon K. Mensah, Benedicta A. Forson, Akua O. Afrane, Yaw A. (April 7, 2021) Larval habitat diversity and Anopheles mosquito species distribution in different ecological zones in Ghana Parasites and Vectors

https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-021-04701-w

Conn, Jan E. Ribolla, Paulo O. (2016) Genetic control of malaria and Dengue Academic Press

https://www.sciencedirect.com/science/article/abs/pii/B9780128002469000053

Rogers, Kara. (November 3, 2024) Aedes Britannica

https://www.britannica.com/animal/Aedes

Ferede, Getachew. Tiruneh, Moges. Abate, Ebba. Kassa, Wondmeneh Jemberie. Wondimeneh, Yitayhi. Damtie, Demekech. Tessems, Baley. (April 23, 2018) Distribution and larval breeding habitats of Aedes mosquito species in residential areas of northwest Ethiopia National Library of Medicine

https://pmc.ncbi.nlm.nih.gov/articles/PMC5968207/#:~:text=Aedes%20mosquito%20potential%20larval%20breeding%20habitats&text=The%20type%20of%20water%2Dholding,and%20plastic%20containers%20(14.8%25).

Rose, Noah H. Baldolo, Athanase. Sylla, Massamba, Akorli, Jewelna. Otoo, Sampson. Gloria-Soria, Andrea. Powell, Jeffrey R. White, Bradley J. Crawford, Jacob E. McBride Carolyn S. (March 10, 2023) Dating the origin and spread of specialization on human hosts in Aedes aegypti mosquitoes National Library of Medicine

https://pubmed.ncbi.nlm.nih.gov/36897062/#:~:text=The%20globally%20invasive%20mosquito%20subspecies,West%20African%20Sahel%2C%20where%20Ae.

Sokol, Joshua. (March 27, 2023) Slave trade records help reveal when first yellow fever mosquitoes bit humans Aedes aegypti may have developed a taste for humans at the birth of the Saharan desert Science

https://www.science.org/content/article/slave-trade-records-help-reveal-when-first-yellow-fever-mosquitoes-bit-humans#:~:text=Some%20500%20years%20ago%2C%20a,ripple%20through%20the%20colonial%20world.

Nava, Martin Reyna. Debboun, Mustapha. (2020) Mosquitos, Communities, and Public Health in Texas Academic Press

https://www.sciencedirect.com/science/article/abs/pii/B978012814545600002X

Moore, Chester G. Mitchel, Carl J. (September 1997) Aedes albopictus in the United States: Ten-Year Presence and Public Health Implications Emerging Infectious Diseases Volume 3 Number 3

https://wwwnc.cdc.gov/eid/article/3/3/97-0309_article#:~:text=1983%20(4).-,Ae.,to%20be%20infested%20with%20Ae.

Culex Mosquitos Global Vector Hub

https://globalvectorhub.tghn.org/vector-species/culex-mosquitoes/

Featured Creature southern house mosquito University of Florida

https://entnemdept.ufl.edu/creatures/aquatic/southern_house_mosquito.htm#:~:text=Both%20males%20and%20females%20take,will%20take%20multiple%20blood%20meals.

(April 16, 2024) Life cycle of Culex mosquitos Center for Disease Control

https://www.cdc.gov/mosquitoes/about/life-cycle-of-culex-mosquitoes.html#:~:text=Life%20stages-,Eggs,%2C%20ditches%2C%20and%20marshy%20areas.

Tascoff, Harrison (October 16, 2019) Malaria in the Amazon Stanford University School of Sustainabiliy

https://sustainability.stanford.edu/news/malaria-amazon