Nothing Personal, You're Just Not My Type; February 1995; Scientific American Magazine; by Mirsky; 2 Page(s)

The world was safe all along. Back in the 1950s, moviemakers regularly served up the spectacle of creatures from other planets attempting to take over our bucolic little orb. Heroic earthlings fought the aliens with dynamite, napalm, atomic torpedoes and bad acting. But had the heroes been better acquainted with life-history strategies--the reproductive behaviors that determine patterns of population growth--they might not have bothered.

In general, says May R. Berenbaum, professor of entomology at the University of Illinois, "none of [the aliens] exhibit the opportunistic sorts of reproductive traits or characteristics of organisms that successfully colonize." Her findings help to explain why earthlings should be afraid of at least some contemporary invaders--such As zebra mussels, bark beetles, medflies and, perhaps, the sluglike aliens featured in one of last year's movies, the Puppet Masters.