Page "Mosquito" Paragraph 57

Blood is directed straight into the mosquito's stomach.

In species that feed on mammalian or avian blood, hosts whose blood pressure is high, the mosquito feeds selectively from active blood vessels where the pressure assists in filling the gut rapidly.

If, instead of slapping a feeding mosquito, one stretches one's skin so that it grips the proboscis and the mosquito cannot withdraw it, the pressure will distend the gut until it breaks and the mosquito dies.

In the unmolested mosquito however, the mosquito will withdraw, and as the gut fills up the stomach lining secretes a peritrophic membrane that surrounds the blood.

This membrane keeps the blood separate from anything else in the stomach.

However, like certain other insects that survive on dilute, purely liquid diets, notably many of the Homoptera, many adult mosquitoes must excrete unwanted aqueous fractions even as they feed.

( see the photograph of a feeding Anopheles stephensi.

Note that the excreted droplet patently is not whole blood, being far more dilute ).

As long as they are not disturbed, this permits mosquitoes to continue feeding until they have accumulated a full meal of nutrient solids.

As a result, a mosquito replete with blood can continue to absorb sugar, even as the blood meal is slowly digested over a period of several days.

Once blood is in the stomach, the midgut of the female synthesizes proteolytic enzymes that hydrolyze the blood proteins into free amino acids.

These are used as building blocks for the synthesis of egg yolk proteins.