The cover of darkness hides an extraordinary evolutionary arms race between bats and moths. “Aerial insectivorous bats use echolocation to navigate and hunt prey,” says Juliette Rubin, PhD student at Boise State University in Idaho. To outmaneuver their predators, silk moths (Saturniidae) have developed an array of anti-bat strategies, from bat-detecting ears and ultrasonic sound production to chemical protection and longer hindwing appendages.
The African moon moth (Argema mimosae) is no different. A recent study showed a 75% success rate in deterring bat attacks.
“From this study it seems that the bat’s sonar reflects off the moth’s hindwings, confusing the bat,” says Rubin. The hindwings seem to draw the bat away from the moth’s body, decreasing capture success.
“Previous studies indicate that moths can fly with reduced or removed hindwing areas, but some fine motor movements seem compromised in this situation.
“Saturniidae moths spend most of their life as caterpillars, eating, growing and preparing for pupation – during which they metamorphose into moths,” explains Rubin.
The African moon moth caterpillar relies on torchwood (Burseraceae) and cashew (Anacardiaceae) trees to pupate. They spend a week in moth form, dedicated to breeding. It is during this time they are at risk from bat attacks. Males fly frequently, seeking out mates, and are more likely to encounter bats.
There are an estimated 2 300 species of silk moths, many occurring on the African continent.
Written by Georgina Lockwood
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