Cockroach Wars

May 23, 2013 - 2:36 PM
This image made from video provided by Ayako Wada-Katsumata shows glucose-averse German cockroaches avoiding a dab of jelly, which contains glucose, and favoring the peanut butter. For 30 years, people have been getting rid of cockroaches by setting out sweet-tasting bait mixed with poison. But in the early 1990s, a formerly effective product stopped working. Some cockroaches had lost their sweet tooth, rejecting the corn syrup meant to attract them. Later studies showed they were specifically turned off by the sugar glucose in the syrup. Scientists reported Thursday, May 23, 2013 that the key is an altered behavior of certain nerves that signal the brain about foods. (AP Photo/Ayako Wada-Katsumata)