Why Do Mosquitoes Drink Blood?

Female mosquitoes drink blood to produce viable eggs. The proteins and iron in blood are essential for mosquito egg maturation, meaning that a blood meal is a crucial part of their reproductive cycle. Different species of mosquitoes show host preferences and, in many cases, have narrow restrictions as to their host animals. Females of the species Uranotaenia sapphirina, for example, feast mainly on earthworms and leeches and do not bite humans. Male mosquitoes and non-fertilized females feed on flower nectar and are known pollinators.

When a female mosquito bites, it uses its specialized mouthparts to pierce the skin and access blood vessels. The mosquito injects saliva into the host, which contains anticoagulants to prevent the blood from clotting. This allows the mosquito to feed efficiently. The saliva, however, triggers an immune response in humans, leading to the familiar itching and swelling associated with mosquito bites.

While feeding on blood, mosquitoes can transmit various diseases to their animal hosts. Several species are vectors for serious illnesses such as malaria, dengue, and Zika virus. The transmission occurs when a mosquito ingests blood from an infected host and later bites another host, passing on the pathogens. Indeed, mosquitoes are one of the deadliest animals to humans, and they are responsible for spreading diseases that cause significant morbidity and mortality worldwide.