Yet another video is circling my facebook feed, once again with cries of “What is that?!” coupled with either “Eww gross!” or “What are you talking about that’s super cool!”
Here is the video in question, and you should go ahead and turn on the sound.
While I admit that the camouflage is well done, if you freeze the video and search for basic body plan, it’s actually fairly simple to spot what it is. Well, at least, more simple than it was the last time.
So, what is it, and what is it doing?
It is a moth, more specifically Dudusa sphingiformis, which has undergone an interesting revisiting of the basic moth body plan. Instead of having the wings lay flat across its back, they are angled and kept down at the sides. It also has a funny mossy growth on the end of its abdomen, as well as a strange coronet running between its head and thorax.
It is found in Asia, most notably in Japan, Korea and Nepal. They are part of the Notodontidae family of moths, which means that the adults do not feed, but rather reserve their energy as grown ups to mate and reproduce. In the video description, this display is characterized as a courtship display, meant to entice the lady moths around. However, others have characterized it as defensive posturing, meant to scare off a predator rather than attract a female.
This seems to be the more likely explanation. First of all, both sexes look like this, which would be pointless if the tufts were only necessary for a male courtship display. Furthermore, they both respond in this way if prodded or poked*, rather than if they are in the vicinity of a moth of the opposite sex. Also note that the movement puts one in mind of a scorpion attacking, which might be a useful and deadly arthropod to imitate.
So, why bother going through all of this trouble?
According to researchers, this moth has no other defensive mechanism that is common amongst moths or butterflies. It is not poisonous or distasteful, nor does it possess a color pattern to mimic another poisonous or distasteful species. It does not have irritating hairs or scales on its body. Furthermore, it cannot make a quick getaway if the temperature is around 25°C, meaning it has to vibrate its wings and warm up for over a minute before it can fly. Therefore, it seems to have devised a way to freak out a potential predator to buy itself some time before it can make its escape. The motion, the noise, all of it to distract a potential predator while it warms up the engines enough to fly away.
So, for me, I’m going with cool. Maybe not the best defensive strategy ever to come out of the evolutionary process, but cool all the same.
*To read more, see The aggressive defence mechanism of a Himalayan moth available at http://images.peabody.yale.edu/lepsoc/nls/2000s/2007/2007_v49_n2.pdf