Missouri Master Naturalists- Springfield Plateau Chapter

Tuesday, August 2, 2011

Giant Leopard Moth

Giant Leopard Moth
One advantage of being in Master Naturalists is that friends bring you lots of interesting bugs and plants to identify, a game called "Stump the Chump".  I sometimes have to remind them that "Master Naturalist" is an organization, not a degree.

Larry Whiteley brought this Bass Pro special today.  Fortunately he he had found a uniquely colored moth with an interesting story.  The Giant Leopard Moth, Hypercompe scribonia, is very distinctive with dramatic dark ovals and circles on its dorsal forewings resembling a leopard's spots.  This specimen was long dead so I livened it up on a floral arrangement.


Caterpillar Defensive Position- Wikimedia
Also known as the Eyed Tiger Moth, it is a member of the Arctiidae family which includes Tiger, Tussock and Lichen moths.  Its beautiful hairy caterpillar is related to the Woolly Bear caterpillar, touted as a forecaster of winter weather.  The Tiger Moths get their name from the bold bands of various colors on their dorsal wings.

Tiger Moths have a unique defense against bats, a formidable predator during their nocturnal flights.  They have long been known to produce ultrasonic sounds but now we know a reason why.  A Discover Magazine blog describes sounds the moths emit as interfering with the echolocation system of bats.  We can think of it like a fighter plane jamming a missile's radar signal.  This tactic greatly reduces the bat's successful rate of moth captures.

New studies of bat echolocation from Brown University add to the wonder.  They describe how a bat can isolate the echos of a small insect amidst all the echos from the environment (tree branches, leaves, wires, etc) and those of other bats. Since the attack sequence of a bat lasts less than a second, the moths have to react fast.  Fortunately, the moths can produce up to 450 clicks in one-tenth of a second.