Friday, February 20, 2015

[Entomology / Behaviour • 2015] Moth Tails divert Bat Attack: Evolution of Acoustic Deflection


Luna moth Actias luna
 photo: Geoff Gallice | flic.kr/p/7TwV7q

Abstract
Adaptations to divert the attacks of visually guided predators have evolved repeatedly in animals. Using high-speed infrared videography, we show that luna moths (Actias luna) generate an acoustic diversion with spinning hindwing tails to deflect echolocating bat attacks away from their body and toward these nonessential appendages. We pit luna moths against big brown bats (Eptesicus fuscus) and demonstrate a survival advantage of ∼47% for moths with tails versus those that had their tails removed. The benefit of hindwing tails is equivalent to the advantage conferred to moths by bat-detecting ears. Moth tails lured bat attacks to these wing regions during 55% of interactions between bats and intact luna moths. We analyzed flight kinematics of moths with and without hindwing tails and suggest that tails have a minimal role in flight performance. Using a robust phylogeny, we find that long spatulate tails have independently evolved four times in saturniid moths, further supporting the selective advantage of this anti-bat strategy. Diversionary tactics are perhaps more common than appreciated in predator–prey interactions. Our finding suggests that focusing on the sensory ecologies of key predators will reveal such countermeasures in prey.

Keywords: antipredator defense; bat–moth interactions; Lepidoptera; Saturniidae


Jesse R. Barber, Brian C. Leavell, Adam L. Keener, Jesse W. Breinholt, Brad A. Chadwell, Christopher J. W. McClure, Geena M. Hill and Akito Y. Kawahar. 2015. Moth Tails divert Bat Attack: Evolution of Acoustic Deflection. PNAS. doi: 10.1073/pnas.1421926112


Why Do Luna Moths Have Such Absurdly Long Tails? http://on.natgeo.com/1D5tpvs via  @ngphenomena
Luna moths’ gorgeous wings throw off bat attacks  http://po.st/ZV8dO9 via @SmithsonianMag

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