I have been taking photographs of butterflies for a long time, and I have some photos that I consider pretty good. However, I have had a hard time getting photos that I really like of monarchs. I think I figured out why, but that only posed another question.
Monarchs have a series of white spots on a black background that break up their profile, and hide their eyes.
My definition of a good butterfly photograph usually starts with the eyes being in focus. Here the eye is in focus, but you don’t really notice it.
And another shot–the eye is clearly in focus, but not obvious to look at.
One would assume this is a defensive mechanism–a predator might attempt to strike the monarch and miss the eye and head. But what predator? Monarchs are toxic to birds. Most insect predators would be too small. Maybe defense against lizards? Lizards would not be a big issue here in the north, but might be further south.
I looked at my other butterfly photographs to see which ones have similar spots. Soldiers and queens, the other milkweed butterflies, have spots that are similar. Viceroys, red-spotted purples, white admirals, spicebush swallowtails, and black swallowtails all have white spots which might disrupt the coloration and hide the eye, but to a much lesser extent than the monarch.
Typically, brushfoot butterflies have an eye color that is the same as the ground color of the butterfly. For example, the mourning cloak:
And the red admiral:
And the common buckeye:
The major exception I found was the little wood satyr, which has black eyes on a brown body.
Skippers and gossamer wing butterflies tend to have black eyes.
Here is a coral hairstreak:
The western pygmy-blue has blue-gray eyes, but they match the ground color of the butterfly:
Of course, some butterflies like hairstreaks have eyespots on their wings, which can divert predators (thought to be mainly jumping spiders) from their heads.
Why do monarchs and other milkweed butterflies hide their eyes? What particular predator is this a defense against? Let me know if you know.