Mosquitoes need to feed on blood in order to obtain the proteins and iron necessary for the development of their eggs. However, they do not need to consume large quantities of blood in order to become full. Here are some key facts about how much blood mosquitoes drink and how many bites it takes to fill them up:
How Much Blood Do Mosquitoes Consume?
A female mosquito needs between 0.00001 – 0.00003 milliliters of blood in order to get a full blood meal. This is equivalent to approximately 0.0000035 – 0.00001 fluid ounces or 0.00000006 – 0.0000002 cups. These tiny amounts are still enough to allow the mosquito to produce a batch of eggs.
Number of Bites to Fill Up
Most female mosquitoes take between 1 – 3 bites in order to get a complete blood meal. Here are some specifics:
- Aedes mosquitoes (vectors of diseases like yellow fever, dengue, Zika): Usually fully feed with just 1 bite
- Anopheles mosquitoes (malaria vectors): May take 1-3 bites for a full meal
- Culex mosquitoes (West Nile virus vectors): Typically need 2-3 bites to fill up
So for most mosquito species, the answer is 1-3 bites provides them with enough blood to get fully engorged.
Why Don’t They Keep Drinking Blood?
There are a few key reasons why mosquitoes stop after getting just a tiny amount of blood:
- Their stomachs are physically limited in size. With an engorged stomach, they can no longer fly effectively.
- There are sensory receptors that detect stretch in the stomach and signal the brain to stop feeding.
- Blood coagulates quickly, so that limits how much they can consume from one area.
- Feeding for too long increases risk of being smacked by host.
Getting more than the minimum amount needed would not provide any benefit and could actually hinder the mosquito’s ability to fly off safely and eventually lay its eggs.
Do All Mosquitoes Spread Diseases?
No, not all mosquito species transmit diseases. Out of over 3,500 mosquito species worldwide, only a couple hundred are known to transmit diseases like malaria, yellow fever, dengue fever, Zika, chikungunya, and West Nile virus. Mosquitoes fall into two broad categories:
| Type | Disease Transmission? | Examples |
|---|---|---|
| Nuisance mosquitoes | Do not spread pathogens | Aedes vexans, Culiseta inornata |
| Vector mosquitoes | Spread diseases | Aedes aegypti, Anopheles gambiae |
Vector mosquitoes have specialized mouthparts and saliva that make them effective at transmitting certain viruses and parasites between hosts. But many mosquito species do not have these attributes and cannot spread disease.
How Does the Mosquito Digest Blood?
Mosquitoes don’t actually have a true stomach. Instead they have a diverticulated midgut where blood is stored, as well as other specialized digestive organs:
- The crop stores sugar water from nectar meals.
- The midgut temporarily stores blood from feeding.
- The hindgut absorbs nutrients.
- The Malpighian tubules filter out waste.
Within about 3-4 days after feeding, the mosquito’s midgut lining secretes proteolytic enzymes that break down the blood proteins into amino acids. These building blocks are absorbed and used by the fat body and ovaries to create yolk proteins for egg production.
The indigestible blood remnants, like hematin, are compacted into a pellet and excreted out of the anus. This leaves the characteristic dark spots seen on walls and fabrics where mosquitoes have been smashed after feeding.
Why Do Mosquitoes Bite Humans?
Mosquitoes are attracted to humans for several reasons:
- Our body heat and CO2 emissions help mosquitoes locate and target us.
- Compounds like lactic acid in our sweat provide short-range cues.
- Our abundance and lack of thick fur makes us easy targets.
- We provide a convenient blood source for egg production.
Mosquitoes that prefer to feed on mammals (mammophilic) will readily bite humans when we encroach on their habitats. And mosquitoes that prefer bird blood (ornithophilic) may still opportunistically bite humans from time to time.
Conclusion
In summary, it only takes 1-3 brief bites for a female mosquito to get a full blood meal that will allow her to develop a batch of eggs. Specific physiological and behavioral factors limit mosquitoes from overeating blood. While not all species transmit disease, mosquitoes that do can spread pathogens like malaria, dengue, and Zika virus very efficiently with their specialized biting and feeding behaviors. Understanding details of mosquito blood feeding can help inform strategies to disrupt disease transmission and control populations.