Discovered: A gene that makes teens easily persuadable; the evolution of fireflies; NASA announces new Mars mission; the Mayans may have brought on their own demise.

More missions to Mars in NASA's future. With the Curiosity rover still scooting around the red planet, NASA has announced plans for a new mission to Mars. In 2016, they'll send a probe to Mars to study the planet's evolutionary history. The InSight lander will penetrate deep into Mars' core, gathering information about its interior composition and tectonic features. NASA is classifying InSight as a low-budget mission. Unable to resist a pun, associate administrator of NASA's Science Mission Directorate John Grunsfeld says, "InSight will get to the 'core' of the nature of the interior and structure of Mars, well below the observations we've been able to make from orbit or the surface." Bruce Banerdt of NASA's Jet Propulsion Laboratory will lead the mission. [Scientific American]

The recent evolution of fireflies. Glowing insects are one of nature's truly mesmerizing wonders. But researchers now think that fireflies haven't been making humans go "ooh" for very long in the grand scheme of things. Peter Vršanský, a palaeobiologist at the Slovak Academy of Sciences in Bratislava, conducted an analysis of insect bioluminescence in order to study the evolutionary history of glowing bugs, and he found that they emerged only tens of millions of years ago. In comparison, the bioluminescent creatures of the sea—imagine those creepy deep sea specimens—have been around for at least 400 million years. Vršanský also believes that glowing land animals may not be around for much longer. "While bioluminescent insects have diversified into 13 known species, most of them are known from a single collected individual," he says. "That suggests they are extremely rare and vulnerable to extinction." [New Scientist]

How genes can make teens easily persuadable. When it comes to peer pressure, some teens' genetics make them unable to just say no. A study conducted by the University of Colorado Boulder's Jonathan Daw shows that teens with two copies of a the short version of the 5HTT gene were more likely to drink and smoke at the behest of their friends. Teens with two long 5HTT genes could easily abstain from bad behavior, while teens with one short and one long gene fell in between. "Our data suggest that, alongside many other influences on adolescent substance use, genetics partly underlie individuals’ susceptibility to peer smoking and drinking," says Daw. Many recent studies have shown that genetics, as well as environment, play a crucial role in behavior. [Science News]

Mayans hastened their own decline. The mystery of why and how the ancient Mayan civilization collapsed has plagued scientists for a long time. Drought is thought to be the main culprit. But researchers at the Columbia University Lamont-Doherty Earth Observatory think that the Mayans may have made the drought worse, partially bringing about their own undoing. Benjamin Cook and colleagues have unearthed evidence that the Mayans cleared away wide swaths of forest, aggravating the drought brought on by a nasty dry spell. "We’re not saying deforestation explains the entire drought, but it does explain a substantial portion of the overall drying that is thought to have occurred," says Cook.  [Columbia University]