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How hawkmoths jam the sonar signals from bats

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In a 2009 article in the Scientific American, Aaron Corcoran, a biology PhD student at Wake Forest University and the lead author of the paper about how tiger moths jam bat sonar, described how scientists studied and tested behavior of the Bertholdia trigona against the big brown bat Eptesicus fuscus, using high-speed infrared cameras and an ultrasonic microphone to record the action over nine consecutive nights.

"Normally, a bat attack starts with relatively intermittent sounds. They then increase in frequency—up to 200 cries per second—as the bat gets closer to the moth "so it knows where the moth is at that critical moment," Corcoran explains. But his research showed that just as bats were increasing their click frequency, moths "turn on sound production full blast," clicking at a rate of up to 4,500 times a second. This furious clicking by the moths reversed the bats' pattern—the frequency of bat sonar decreased, rather than increased, as it approached its prey, suggesting that it lost its target."

But sonar jamming is not the only weapon in the moth's self-defense system. Researchers have known for 50 years that moths have an early warning system: They can hear the ultrasonic hunting calls of their nocturnal predator.

In a 2006 paper in Current Biology, Dr. James Windmill who was at the University of Bristol, England, at the time, wrote that not only was the simply designed moth ear detecting the echolocation pulses of the bat, but it was actually fine tuning its receptivity when under attack.

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