The study, published in the Journal of Experimental Biology, shows that Aedes aegypti mosquitoes can learn to link the smell of DEET with food. Researchers restrained the insects behind a fabric mesh and placed a bag of warm blood just out of reach. When the mosquitoes began to feed, the scientists introduced the scent of DEET. After repeating the procedure four times, more than 60% of the mosquitoes tried to feed when presented only with the DEET odor.
In a second experiment, mosquitoes chose between an untreated hand and one coated with DEET at normal concentrations. Untrained mosquitoes avoided the DEET hand, but trained ones were attracted to it. The same effect appeared when sugar replaced blood as the reward. The team says DEET remains an effective repellent, but users should reapply it and be cautious with treated clothing as concentrations fall over time.
The findings build on earlier work showing that mosquitoes can learn and remember odors linked to blood meals and defensive hosts, and that understanding mosquito behaviour is important as Aedes aegypti expands its range.
Difficult words
- restrain — hold back or prevent movementrestrained
- introduce — bring something in for the first timeintroduced
- repeat — do again one or more timesrepeating
- repellent — a substance that keeps animals away
- concentration — amount of a substance in somethingconcentrations
- attract — cause someone or something to move nearerattracted
- avoid — stay away from or not do somethingavoided
- scent — a smell that an animal can recognise
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Do you think people should change how they use repellents because mosquitoes can learn? Why or why not?
- How could this research affect what people wear or do in areas with many mosquitoes?
- What other simple steps could help reduce mosquito bites besides relying on DEET?
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