Then Pruitt went back to find out how many babies the aggressive colonies produced compared to the more passive ones. He found that the aggressive colonies produced more babies while more of their juveniles survived the storms compared to the passive colonies.
"There's clearly some kind of selection going on here for the aggressive individuals in response to these extreme weather events," Uetz told Wired. "And that's what's really fascinating."
According to the Wired story, Uetz observed a similar phenomenon after a deadly tornado ripped through Montgomery, Ohio, in 1999. Uetz studied wolf spiders in the devastated sections of UC's Harris Benedict Nature Preserve and found differences in populations affected by the storm compared to those that escaped the disaster.
"On the one hand, it's not surprising that natural disasters have an impact on the survival of animals," Uetz told Wired. "But to see their impact on selection, how they actually drive the direction of evolution in a species, is pretty rare."
Uetz has been studying various aspects of spider behavior and communication in his UC lab. In a recent study published in the journal Behavioural Processes, Uetz found that the spider's courtship rituals make them more obvious to blue jays, a major predator. Likewise, their tendency to freeze when they hear the call of a blue jay effectively renders them invisible to nearby birds.