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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Breath So Bad It Could Save Your Life
30 December 2013 3:00 pm
For tobacco hornworms, bad breath might be the key to surviving the night. As their name suggests, these desert-dwelling caterpillars (larvae of the Manduca sexta moth) regularly chomp on nicotine-laced tobacco leaves. Scientists observed that caterpillars feeding on genetically modified, nicotine-free tobacco plants were more likely to disappear during the night than those chowing down on regular tobacco, leading them to suspect that the hornworms might be repurposing the toxic chemical to defend themselves against nocturnal predators like wolf spiders (Camptocosa parallela, pictured above feasting on a larva). The researchers investigated a gene called CYP6B46, which is active in the hornworm’s gut. Turning the gene off resulted in higher nicotine levels in the hornworms’ poop, suggesting that the gene helps the larvae avoid excreting the chemical by pumping it out of their guts and into their blood. The caterpillars had to be exuding the toxic nicotine somehow, so the scientists gave them an insect version of a breathalyzer test and discovered that they breathe it out with every exhale, the team reports online today in the Proceedings of the National Academy of Sciences. This “toxic halitosis” repelled wolf spiders, which actually flee from caterpillars with nicotine on their breath, as you can see in this video. Still, bad breath is no guarantee of a long life: It didn’t deter some of the hornworms’ other predators, including big-eyed bugs and antlion larvae.