Batesian Mimicry in the Immature Flying Gurnard

How far do I have to haul this thing?

   Of late, we have enjoyed some interesting sightings.  On my last swim with Charles, on the Ironman side of the Kailua pier, we found a modestly sized blood crab in an enormous Marlinspike Auger.  Why a hermit crab would choose to haul that 15 cm shell over the coral is a  question for the ages.  But our experience with an immature Flying Gurnard two days ago is even more thought provoking.

   It is widely accepted that some large moths (and a few butterflies) through evolutionary pressure, have developed large spots on their wings as a form of Batesian mimicry.  The large spots suggest the eyes of an owl and in this model deter predators, such as lizards and birds, that are taken by owls as prey.   The polyphemus moth, which ranges over much of North America, is a classic example. 
 

Polyphemus Moth, Dan Mackinnon

   Henry Walter Bates was a British naturalist who studied the insects of the Brazilian rainforest.  He worked for over a decade, collecting and cataloging the insects.  In the process, he noted that the wing pattern of some butterflies closely resembled that of a vastly disparate species.  Back at the Linnaean Society in London, he proposed that one species of butterfly had developed the wing pattern of another less desirable species as a defense mechanism against predators.  While Bates was considering his butterflies, Darwin and Wallace were independently working on the theory of evolution.  Thus, Batesian mimicry was immediately proclaimed as a classic example of this radical new theory of evolution;  the tasty butterflies had evolved the wing pattern of the nearly identical poisonous species.  And, of course, Bates was derided by

God Creating Batesian Mimicry

those who chose not to accept an explanation for the natural world that did not involve a creative deity. (Thanks to Wikipedia from which this information has been condensed.)

    A bit of thought will show that if moths have spots that look like the eyes of an owl, it is not classic Batesian mimicry.  And papers have been written to suggest other adaptive reasons for these large eye-like spots.  Never the less, the idea that the wing spots on large moths have evolved to mimic the eyes of an owl is firmly entrenched.  Not only that, but lots of other animals have eye patterns.  (The Ferruginous Pygmy Owl of Mexico has an eye pattern on the back of his head!)

    With that background, I will bring you back to the cool waters of the inner harbor.  Not out by King Kamehameha's heiau, but right by the sandy beach, where, having completed my swim, I was just getting

Flying Gurnard prior to agitation.

 ready to stand up and remove my fins.  At this climactic moment I looked down to find a small Flying Gurnard.  He was grazing peacefully on the soft sand with his wings tucked in at his sides.  In this posture, he blended in and it required a probing eye to pick him out.  As I approached him for a picture he did something that I had not seen before.  He flitted quickly, simultaneously opened his fins to their full extent and raised his poisonous dorsal spine.  (Gurnards are closely related to scorpionfish.)  Not only that, his colors became instantly more vivid.  I have never seen a more beautiful gurnard!  I proceeded to stalk him across the floor of the lagoon, seeing this behavior four or five more times and capturing a few pictures.

    As a social aside, I spotted the gurnard a few feet away from three chubby adults of a certain age...two matrons and a gentleman.  They had been standing in that very spot, pot belly deep in the lagoon, when I shoved off thirty minutes before, recounting every foible of every person known to them.   And there they stood in full gossip, not the least disturbed that a crazed snorkeler was turning watery doughnuts, hard by their chubby elbows.  (Two ladies taking pictures on the beach were more interested in our exciting observations.)

Flying Gurnard in signal coloration.  Do you see the eyes?

Back at Casa Ono, looking at my photographs, I could not help but be reminded of owl eyes.  Do you see them?  Certainly, the sea is full of classic examples of Batesian mimicry.  Sandra and I saw many Mimic Angelfish in Bali and a few of the poisonous pufferfish that they so faithfully impersonate.  And a few fish (the Devil Scorpionfish with his brilliant red and yellow axillae comes to mind) will flash bright colors, encouraging you to abort your unwise approach. 

Never the less, I can not get away from the image of these eyes peering back at me from the fins of the immature gurnard.  To the best of my knowledge,  there are no owls in the sea.  Thus, I am left wondering just what they might represent from an evolutionary point of view.  And does this similarity between "eyes" on the wings of the gurnard point to the adaptive significance of similar owl eye-like pattern in other animals?

jeff  October 2012