In grizzly bear country, they say it is standard practice to sew tiny jingle bells onto your hiking clothes and to carry a can of pepper spray at all times when on the trail. The constant jingling wards off bears and the spray acts as an effective last minute deterrent in the event you are charged by one of these irritable beasts. They also say that it is easy to identify grizzly droppings because they are packed with jingle bells and smell like pepper spray! I was reminded of this when I recently spotted a beautiful Io (pronounced I-Oh) moth clinging to the wall under one of our museum porch lights. I will explain, so bear with me.
These solid little members of the giant silk moth family (named after a mythical Greek maiden) are known for flashing a pair of startling eyespots when attacked – as a deterrent. Theirs is a classic textbook case of predator evasion. This reflexive action, which involves a spasmodic lifting of the upper wings in order to flash hidden “eyes” on the hind wings, is intended as a visual “pepper-spray in the eye” toward the attacker. To be effective, this action needs to be followed by an immediate escape. Because of the fact that I frequently find detached Io wings scattered under this very light tells me that this defense is less than perfect. The presence of pepper-spray wings, pulled off by hungry birds, is akin to finding a pile of human-enriched bear dung.
I was, in fact, quite surprised to find a whole Io moth under the light for a change, so I took the opportunity to photograph it. This individual was a male with bright yellow upper wings. The females have more matronly proportions and have reddish brown upper wings. Both sexes possess the startling eyespots on their hind wings. It took a little prompting, but I managed to persuade the moth into flashing those famous eyespots (see below). His enthusiasm was less than impressive and he failed to drop off after doing it, but the act was photographically adequate.
Oddly enough, another “eye-spot” moth was perched on the morning wall beneath the Io. It was a nice example of a Blind-eye Sphinx. These medium sized moths rest with their wings folded back like withered leaves in order to blend into the background. Their black-bordered blue eye spots are subtle but potentially effective. I was unable to persuade this fellow to flash even when I called him a “do-nothing butterfly” and “a glorified house fly.” Nothing worked except my finger physically pushing the upper wing away to reveal the secret eyes beneath.
Perhaps these two moths were in a stupor – their brains fried by the electromagnetic waves of the porch light. They would soon both be bird bait there on the wall, so I carefully plucked them off and took them home for some more photo work. Positioned on the bark of one of my backyard maples, the Io and sphinx looked a bit more natural but were still unresponsive. The Sphinx blended in so well that it was near impossible to see (see here) while the lemon-colored Io stood out like a Greek goddess at a weight-watchers meeting. I left them both to safely enter the night and fly away.
By the next morning, they were both gone. I assume the superbly camouflaged sphinx made good his return to the night air without needing to “flash wing” at a predator. His Greecian friend, however, did not fare as well. A single battered hind wing lay on the ground as mute testimony of a fatal run-in with a hungry bird (see below). Apparently jingle bells and pepper spray can only go so far.