Are mosquitos attracted to black skin?

Mosquitoes are attracted to several things:

The number one attractant is carbon dioxide; followed closely by their attraction to body heat. This is on reason why heavier persons seem to get bitten more often than average size people. Mosquitoes often are said to be attracted to dark clothing. This has less to do with the color rather than the fact that dark clothes tend to trap more heat than lighter-colored clothing.

Another form of mosquito attraction is smell. Different people give off different odors. Largely based on human genetics factors such as blood type and cholesterol levels, even the skin's steroid or uric acid content changes our attractiveness to various species of mosquito. Depending on your diet, stress level, or the moisture in your skin, a group of mosquitoes might be swarming you while a nearby friend is left in peace. This may elevate your stress level which may cause you to emit more odor and moisture, which causes more mosquitoes to become attracted to you.

Men tend to get bitten more often than women do.

It is also said that ethnicity may play a minor role in mosquito attraction as well. Caucasians have a tendency to have much more moisture in their skin than other ethnicities do. Also a caucasian's light skin shows more visible contrast against their surroundings, giving mosquitoes a much more visible meal. Whereas other ethnicities with darker skin tend to provide less contrast against some surroundings. There has been insufficient research on this point to allow you to draw broad conclusions.

There is similarly unproven (anecdotal) evidence that scented toiletries draw more mosquitoes.

Keep in mind-- not all species of mosquitoes bite humans. Some feed instead on other animals, and some even prefer to feed on the larvae of other species of mosquitoes. And within a species, although most female mosquitoes need to suck blood to nourish themselves for reproduction, they may also drink nectar. Of those species, the males only obtain sustenance from plant sugars such as nectar from flowers.