"Is that a butterfly?"
"No, it’s just a moth."
That exchange is an example of the most common conversation that happens regarding moths; what most people know about moths is "they are not butterflies." Recognizing the importance of moths, a growing group now celebrates their diversity and importance with the annual National Moth Week, happening right now.
Things you might not know
You probably know that moths start out as caterpillars. If you didn’t, you do now.
You probably didn’t know that there are about 11,000 species of moths in the United States alone. That is more than all the bird and mammal species we have. There are 10 times more moths than butterflies. There are moths so tiny that you can barely see their wings; the largest moth species in the United States is the Luna moth with a wingspan of 4.5 inches.
Even more interesting, what the Luna Moth has in wings, it lacks in a mouth. It has no mouth at all. The only purpose this moth has is to mate and produce moth eggs. That’s it. Because it has no mouth, it must do this in about a week before it uses all of its energy and dies.
Most moths are fuzzy and that makes them great pollinators. Their fuzz collects and deposits pollen on every flower where they land. Now, it is true that some caterpillars (that become moths) can wreak havoc on some of your crops and plants. But most don’t.
Moths and their younger caterpillar selves are far more beneficial than harmful, and that includes being food for other animals. Almost 90% of birds depend on moths or caterpillars for food, more evidence that they are an incredibly important part of any ecosystem.
Finally, moths have some incredible adaptations. Giant silkworm moths can use their antennas to smell a female moth seven miles away! Some moths disguise themselves to hide from others, and this includes some that even look like bird poop. And tiger moths produce a clicking sound that jams a bat’s sonar system so they can’t be found and eaten.
Moths and lights
Turn on a porch light and the moths coming running (flying, actually). Why? This happens because most moths are nocturnal, and they evolved to travel by the light of the moon. They keep the moon in sight to help them keep track of where they are. Remember, in evolutionary history, our lights have not been around long at all.
An artificial light acts like a bright stimulant to the moth that it cannot resist. A moth’s goal is to find food (if it has a mouth) and find a mate. The artificial light distracts them from the goal. Often, the distraction is so strong that the moths never leave the light and they die. Scientists agree that our lights have accidentally caused evolutionary chaos to the moth species, and their numbers are falling because of it.
There are early signs that some moths are already evolving to our artificial light. Scientists in Switzerland collected and raised about 1,000 moths – some from the country, and some from the city. They put the moths in a dark room with an artificial light at one end. Nearly 100% of the country moths immediately went to the light, while only about 67% of the city moths went to the light. The other city moths ignored it. Scientists say this could be a sign that moth generations produced in places with lots of lights are evolving away from the deadly tendency.
Have a moth night
Celebrate National Moth Week or any summer night by setting up a moth wall. It’s easy, fun, and super educational.
On a warm and calm night, hang a sheet between two trees or posts in your yard.
Shine a light on one side of the sheet and moths will quickly start landing on the sheet.
Observe and take pictures of the moths and upload to the free iNaturalist app to help you identify them. Join the iNaturalist group "CoMo Eco Challenge" to view all the moths collected in our area.
Mike Szydlowski is science coordinator for Columbia Public Schools.