Bernie Myers, age 11, of Richmond, Virginia, for his question:

Do mosquitoes also bite animals?

Right now, a cruel epidemic of sleeping sickness is killing hundreds of our horses. The virus that causes this disease is carried and transmitted by mosquitoes. These blood sucking insects attack many warm blooded and cold blooded animals. Some viruses are injected by bites; others are left on the skin by a mosquito's sticky feet. We know that these insects transmit at least ten serious infections to humans. Goodness knows how many they spread through various populations of the animal kingdom.

There are at least 2,000 species of mosquito living from the tropics to the polar regions. Some species bite frogs, toads and other cold blooded creatures. Some species live in jungles and prefer to attack the monkeys. Other species attack birds, pigs, cattle or horses. Several species found in torrid, temperate or polar regions prefer to bite human beings. Few land animals are mosquito proof and hungry hordes of mosquito larvae even attack fishes and other creatures in the water.

However, half of the world's mosquito population dines only on plant juices. Only the female mosquito attacks people or animals. This, we think, is because the male's beak is too weak and fragile to pierce through skin. Both the male and the female are limited to liquid food. The male is limited to sipping sap from tender foliage. The female is a pesky blood sucker and some species may need at least one liquid red meal to develop their eggs. The females of a few species prefer plant sap and some of the blood suckers resort to plant sap when no animals or people are available.

Actually the female mosquito has no teeth and her so called bite is a cunning stab. That beak of hers is a fantastic tool kit, kept inside her bag shaped lower lip. Her light body comes in for a light weight landing on the victim's skin. Then she gently feels around for a soft spot and starts her delicate operation. Her kit bag rolls back as she stabs the skin with jabbers so small that the victim does not feel them. She uses a sort of hypodermic needle to inject the flesh with a saliva mixture that prevents the blood from clotting.

This part of the operation is completed without alerting the victim. Then the wretched creature syphons up a helping of liquid blood. She may gorge herself with a meal that weighs more than she does. Then she gently withdraws her stabbers, and whisks herself away. However, the substance injected to keep the blood liquid may stir up all sorts of chemical reactions in the cells around the would. This is what makes the area itch and swell    and this painful sting may last several days.

The virus that causes deadly encephalitis in horses does not kill off the mosquitoes that carry it. It does not appear to be fatal to infected pigs and cattle, though they can transmit it to horses and other creatures. But as a rule, the epidemic is introduced into a region by female mosquitoes that attack a variety of animals.