Rothschildia (Saturniidae) transparent 'windows' function to mimic avian predator, not to aid in dead leaf camouflage
Rothschildia is a genus of Saturniid moths found in the Americas. Rothschildia exhibit four transparent “windows,” one in each wing. What function do these play? The dominant hypothesis is that these windows help to disguise the moths as dead leaves, appearing as holes in a rotting leaf. But the interspecific interactions of this species have been little studied and this hypothesis is merely speculative. Through my observations of bird-Rothschildia interactions in El Oro Province, Ecuador, I present evidence of an alternative hypothesis.
I observed 45 different individual birds of eleven different species mob a Rothschildia for nearly fifteen minutes. Uttering alarm calls and with raised crests, the birds appeared agitated and alarmed. The birds exhibited the same behavior in response to the moth as they typically do to a raptor or other potential predator. These observations provide evidence that rather than camouflaging the moth as a dead leaf, the ‘windows’ instead serve to transform the avian perception of Rothschildia from a prey item into a potential predator.