Lately Symmerista moths have come to the lights at our cabin, and we found one at a rest area along Interstate-75. An odd one showed up at the lights in the wee hours (2:51 am) of July 26. It was quite fluttery and not stopping at first for photos. It seemed weighted-down, and something dark was apparent at the end of its abdomen, possibly another moth?

Eventually the Symmerista settled with its own wings tucked under the wings of its hitchhiker and I was able to concentrate on getting enough light to reveal the identity of a second moth, firmly attached by the end of its abdomen to the end of the Symmerista’s abdomen. I know that sometimes the female of a moth species looks very different from the male, but this smaller, dark moth was a completely different shape than the Symmerista. It looked like a very big tortricid.

Which it was! I have encountered the Large Aspen Tortrix (Choristoneura conflictana) before.

This one was locked in attempted copulation with the larger Symmerista. I tried to measure the length of each of the two moths, but the larger, dominating Symmerista was not about to keep still. It hopped onto the ruler, so I used the opportunity to photograph the two moths from beneath and in profile to show their connection.

The Symmerista took flight from my ruler and landed on my shirt. In this view I could not see the tortricid. On closer examination I could see the tortricid’s back end, so it must have been more sharpIy folded under the Symmerista. The Symmerista flew again and landed at the window beyond which a UV light beckoned. After another flight the pair landed with the tortricid’s wings beneath the Symmerista’s. The Symmerista took off again and I lost track of it in the darkness. The tortricid’s movement was totally at the whim of the Symmerista.

Soon after all this I found a lone Symmerista (below) and snapped a photo to see if I could figure out if this was the same moth minus its partner. A close-up view on my laptop revealed some differences in markings. Also, I could see this new Symmerista had pectinate antennae, while the coupled moth lacked any branching on the antennae. This indicates that the mating Symmerista was a female, and this new moth was a male. The copulating pair was probably somewhere off in the darkness.

How could such a mismatch happen? My guess is that the air was laden with pheromones of both species, and the coupled moths managed to back into the wrong mate. While this coupling wouldn’t result in hybrid offspring (they are not even in the same family!), this certainly reveals how possible it could be for closely related species to hybridize.

I don’t know if this sort of thing is observed very often! I felt it was especially important to document. I’m interested in hearing about whether other people have found mismatched moths.