Do Mosquitoes Like You?
Arts & Humanities
Scientists have discovered that what repels mosquitoes might be more important than what attracts them.
Before reading, write the words attract and repel on a board or chart. Ask students to tell what those words mean to them. Accept all reasonable responses.
Next, introduce these words that appear in the News Word Box on the students printable page: attract, repellent, chemical, odor, powerful, and natural. Discuss the meanings of any of those words that might be unfamiliar. Then ask students to use one of those words to complete each of these sentences:
Suzie placed a piece of cheese on the mousetrap in order to _____ a mouse. (attract)
Some gasoline includes a _____ that helps to lubricate a cars engine as it runs. (chemical)
The potato chips were made with no chemicals. They were made with all _____ ingredients. (natural)
The smell of Mrs. Ryans perfume was so _____ that people turned her way as soon as she walked into the room. (powerful)
To keep beetles away, Uncle John sprayed a _____ on his rose bushes. (repellent)
The ____ of freshly baked pies filled the air inside the house. (odor)
Read the News
Click for a printable version of this weeks news story Do Mosquitoes Like You?.
Reading the News
You might use a variety of approaches to reading the news:
Read aloud the news story to students as they follow along.
Students might first read the news story to themselves; then you might call on individual students to read sections of the news aloud for the class.
Photocopy the news story onto a transparency and project it onto a screen. (Or use your classroom computer's projector to project the story.) Read the story aloud as a class, or ask students to take turns reading it.
Arrange students into small groups. Each student in the group will read a paragraph of the story. As that student reads, others might underline important information or write notes in the margin of the story. After each student finishes reading, others in the group might say something -- a comment, a question, a clarification -- about the text.
More Facts to Share
You might share these additional facts with students after they have read this weeks news story.
Researchers have identified a handful of the body's chemical odors -- some of which may be related to stress -- that are present in significantly larger concentrations in people that mosquitoes are happier to leave alone. The odors repel the mosquitoes. When the combination of human odors is wrong," Dr. James Logan says, "the mosquito fails to recognize this signal as a potential blood meal."
It has been known for some time that mosquitoes are attracted to humans by blends of common chemicals such as carbon dioxide, released from the skin and by exhaling, and lactic acid, which is present on the skin, especially when we exercise. But everyone produces those attractant chemicals that mosquitoes seem to like. None of those chemicals explained why mosquitoes preferred some people over others. Dr. Logan and his colleagues have discovered repellent chemicals" that may mask the attractive chemicals or may confuse" mosquitoes so they cannot recognize the attractive odors.
Mosquitoes cause hundreds of millions of cases of disease each year. For example, as many as 500 million cases of malaria are reported each year around the world; more than one million people die from it. Mosquitoes can also spread West Nile virus, dengue fever, yellow fever, and other illnesses.
The Wall Street Journal reports that Dr. Logan and his colleagues separated human volunteers into two groups: those who were attractive to mosquitoes and those who weren't. They then put each of the volunteers into body-size foil bags for two hours to collect their body odors. Using a machine known as a chromatograph, the scientists were able to separate the chemicals. They then tested each of them to see how the mosquitoes responded. By attaching microelectrodes to the insects' antennae, the researchers could measure the electrical impulses that are generated when mosquitoes recognize a chemical. The chemicals were then tested to determine their impact on actual biting behavior. Volunteers put their arms in a box containing mosquitoes, one arm coated with repellent chemicals and the other without, to see if the arm without the coating got bitten more.
Some of the chemicals researchers identified are believed to be related to stress, Dr. Logan says. He suggests that mosquitoes may deem hosts that emit more of those chemicals to be diseased or injured and "not a good quality blood meal."
Use the News
Print out this weeks Use the News printable page for students. Or use the questions on that page to check student comprehension.
Use the News: Answer Key
1. Scientists say the human body gives off 300 to 400 different chemicals.
2. They will use the information they have learned to try to create natural mosquito repellents.
3. Repellents often evaporate.
4. DEET is the common repellent chemical that can be unsafe when used in large amounts.
6. False. They have discovered seven or eight chemicals that repel mosquitoes.
8. False. Scientists hope the new repellents will be available in a year or two.
10. False. DEET is not a natural chemical.
Think About the News. Accept reasoned responses. For example: When some people think of soup, they think of a mixture of many ingredients. Our air is a mixture of many things, most natural but some from other man-made sources.
Use the Use the News printable page (above) as an assessment. Or have students work on their own (in their journals) or in their small groups to respond to the Think About the News question on the news story page.
Lesson Plan Source
LANGUAGE ARTS: English
GRADES K - 12
NL-ENG.K-12.2 Reading for Understanding
NL-ENG.K-12.12 Applying Language Skills
PHYSICAL EDUCATION AND HEALTH: Health
GRADES K - 4
NPH-H.K-4.2 Health Information, Products and Services
GRADES 5 - 8
NPH-H.5-8.2 Health Information, Products and Services
GRADES 9 - 12
NPH-H.9-12.2 Health Information, Products and Services
GRADES K - 4
NS.K-4.3 Life Science
NS.K-4.5 Science and Technology
NS.K-4.6 Science in Personal and Social Perspectives
GRADES 5 - 8
NS.5-8.3 Life Science
NS.5-8.5 Science and Technology
NS.5-8.6 Science in Personal and Social Perspectives
GRADES 9 - 12
NS.9-12.3 Life Science
NS.9-12.5 Science and Technology
NS.9-12.6 Science in Personal and Social Perspectives
See recent news stories in Education Worlds News Story of the Week Archive.
Article by Gary Hopkins
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