Eye spots of moths and butterflies that are revealed with a sudden flick of the wings are widely accepted as a signal to scare or confuse predators. If you have ever seen the up-side down stance of an Eyed Silkmoth that feels threatened you can easily imagine that a hungry bird might be scared away from this fat clumsy morsel that suddenly resembles a cat or an owl. And maybe the scare even works as a defense against the attack of a lizard?
|Antheraea oculea (Western Polyphemus Moth)|
But this isn't where the relationship ends. Evolution has linked insects and reptiles through more than just the food chain.
Papilio rutulus (Western Tiger Swallowtail) caterpillar
Observe the spots on the bloated body of the Western Swallowtail caterpillar: to my eye they not only distract from the real head that remains tucked down and hidden, they also seems to suggest the face of a snake.
|Elephant Hawkmoth, Deilephila elpenor by Amy MacDonald|
When my friend Alex Pelzer was working on his Ph.D. using these moths as his model, we tried to test whether birds are indeed afraid of the snake mimic. At the time, I had a young tame Jackdaw (small corvid). When offered the big writhing worm the bird seemed confused, but then attacked the caterpillar and tried to eat it.
|My trusting friend Jakob the Jackdaw|
So instinctive aversion? Not really.
But: the jackdaw was young, hand-raised and inexperienced. Like young wolves, chimpanzees, and humans, the highly social and intelligent corvids are born with very little instinct. Instead, they have a great capacity for learning. In fact, this young bird looked to me for approval of any new food it found, and it would try to eat everything I offered. So he wasn't a good test animal at all, we should have tried something more precocious, like a young chicken. We just all had a lot to learn.
|Macacha (Fulgora laternaria) by Leonel Baldoni|
My friend Lois O'Brien is an expert of the group Fulgoromorpha. She writes:
To humans this planthopper looks so dangerous that there is a widespread legend that its bite kills within 24 h - the only antidote being to have sex before that time runs out. O'Brien speculates whether the 'alligator mimicry' targets birds, reptiles or monkeys, even humans, and wonders about the size difference between model and imitator. As baby alligators are quite small and quite ferocious hunters (and often under the fierce protection of their really terrifying mother), the size difference bothers me less than the difference in habitat between presumed model and mimic. But birds and monkeys get around ... and maybe they are wary enough of alligators to carry the image in their memory wherever they go.
|Fulgora laternaria from Cuvier's La Regne Animal|
But if all else fails, Fulgora can still flash two big eye-spots at the attacker as well.
|Chrysalis of Dynastor darius stygianus (photo V. Izerskyy)|
We found another unexpected reptile imitator closer to home:
|Do you see the snake lurking?|
But - overemphasized detail aside - I had had my morning coffee already! - so to me it was just a sleepy moth, a beautiful Glover's Silkmoth.
|Glover's Silkmoth (Hyalophora columbia gloveri)|
Literature: The Wild Wonderful World of Fulgoromorpha, L. O'Brien, Denisia 04, zugleich Kataloge des OOe. Landesmuseums, Neue folge Nr. 176 (2002) pp 83-102