Annoying as they are, you may want to think twice before you crush a cockroach or swat a fly-you could be killing a future foot soldier in the war on terror. Increasingly, scientists are turning to insects and other creatures for better ways to identify biohazards. â€Cockroaches can detect all kinds of things, from anthrax spores to DNA,â€ says Karen Kester, an entomologist at Virginia Commonwealth University. With $1 million in funding from the Pentagon´s Defense Advanced Research Projects Agency (Darpa), Kester is studying ways to use roaches and houseflies as toxin sentinels inside contaminated buildings or subways. This, of course, spares humans the job, and it may prove more effective than mechanical sensors, which often lack the range and sensitivity of their living counterparts.