It happens every summer. You’re outside enjoying some time with mother nature, minding your own business, when out of nowhere, you feel a slight sting. You look down, and there’s a pesky little creature sucking your blood again.
And no, it’s not America’s favorite vampire Edward Cullen. It’s a mosquito.
Pamela Lovejoy, Ph.D., assistant professor of biology at SJC Brooklyn, answered a few questions about the blood-sucking bugs.
OnCampus: Starting with the very basic question, why do mosquitoes bite humans?
Pamela Lovejoy, Ph.D.
Dr. Lovejoy: Mosquitoes drink blood because it is a good source of nutrients. Mosquitoes, like other flies, butterflies and bees, have three life stages: larvae, pupa and adult. The larvae live in aquatic environments that are not very rich in certain nutrients, like iron. Female mosquitoes feed on blood as adults to obtain enough nutrients to produce eggs. Male mosquitoes do not drink blood because they do not produce eggs. If you get bitten by a mosquito, it is a female mosquito. There are many species of mosquito, and some bite humans, but others prefer birds or other mammals and do not bite humans.
OC: What about their bite makes us itchy?
Dr. Lovejoy: While mosquito bites are generally painless, the itch afterwards is a reaction by your body to the bite. The bite triggers an immune response from your body, which causes the inflammation and itchiness you feel. Some people have very minor reactions, while others can have bad swelling. If a person is bitten by a mosquito species that they have never encountered before, they may have a larger reaction than to one they experience frequently.
OC: Why do mosquitoes bite some people more than others?
Dr. Lovejoy: Unfortunately, there is no one right answer to this question. Mosquitoes are attracted to the amount of carbon dioxide that we breathe out, and they can also sense body heat and certain molecules in body odor. These factors, along with having certain genetic variants, may make a person more attractive than others to mosquitoes. This being said, nobody is immune.
OC: Are mosquitoes necessary to our ecosystem?
Dr. Lovejoy: There are many species of mosquitoes on Earth — about 3,500 known species. Only a few of those species bite humans. Mosquitoes have been on earth for more than 100 million years and so have had time to coevolve with many different species. Mosquitoes also play an important role as a food source for many fish, bird, and bat species. There is controversy among scientists whether the roles that some mosquitoes play in the ecosystem is essential or not.
OC: Aside from using bug spray, what are some ways to help prevent mosquitoes from biting you?
Dr. Lovejoy: In general, the best way to keep mosquitoes from biting you is to use bug spray. However, spraying chemicals like DEET directly on your skin can be hazardous. There are some organic and natural bug sprays out there which can be safer, but they tend to be much less effective. Some products claim to produce a subsonic sound to deter mosquitoes, but those do not work at all.
Another way to reduce mosquito bites is to reduce mosquito habitats if possible. Mosquitoes lay their eggs in any available standing water, like tree holes, old tires, toys that are left outside, or birdbaths. Removing or frequently emptying these water sources eliminates possible mosquito habitats.
It is also helpful to physically prevent mosquitoes from getting to you. Cover gaps in your home, for example in screens or doors, that would allow mosquitoes to enter. When going outside, wear long sleeves and long pants to reduce exposed skin. Some mosquitoes can bite through thin clothing, however. Stay indoors if possible, especially when certain mosquito-borne illnesses such as West Nile or EEE have been reported in your area.
OC: Why is it potentially harmful to spray DEET directly on your skin?
Dr. Lovejoy: Products with DEET are approved by the EPA to be sprayed directly on your skin. DEET products should not be harmful if applied correctly, but can cause reactions in some people. The percentage of DEET can vary drastically from product to product, so this is important to pay attention to.
In order to avoid reactions, products with DEET can be sprayed on top of clothing to prevent mosquitoes from biting through. DEET products should never be sprayed on cuts or directly on the face. If you do apply DEET to your skin, wash it off as soon as it is not needed. Wash treated clothing before wearing again as well. DEET products should not be sprayed under clothing, and they should not be used on very young children.
Research on DEET seems to determine that it is broken down in the environment relatively quickly, so it is not considered a risk to wildlife.
