One of the neat things about hairstreak butterflies is they display a behavior known as “wing rubbing.” Wing rubbing is an amazing behavior that acts as a deterrent against birds and other predators.
It seems that birds typically grab a butterfly by its head. When a butterfly is captured in such a manner, it has little to no chance of surviving. However, if a predator attacks a butterfly from the rear, there is a greater chance that the butterfly will survive the attack.
Remarkably, the hairstreak butterfly displays what appears to be a false head on the rear margin of its hind wings. If you will look closely at the picture of a grey hairstreak that accompanies this blog, you will notice its rear wings feature orange eyespots that a predator might mistake for eyes. In addition, the hindwings are equipped with tiny hair like “tails” that look much like a butterfly’s antennae. To make the ruse complete when a gray hairstreak is nectaring on a flower, it constantly rubs its hindwings together. If a gray hairstreak is lucky, when spotted by a hungry predator, the combination of the false eyes, and fake antennae and hind wings slowly moving back in forth, often results in the bird trying to grab the butterfly by its hindwings instead of its true head and body. When this happens, the butterfly can fly to safety having lost only a portion of its wings.
Recently I watched a gray hairstreak nectaring for more than five minutes on goldenrod blossoms. The entire time the butterfly dined, it was rubbing its hindwings slowly back and forth.
