By Constance Taylor
Perusing the shelves of the library looking for reference books about moths, I couldn’t find a single one. There were books dedicated to termites, lobsters, crabs, coral, slugs & snails, the friggin’ kraken- the dozens of books about butterflies I found mentioned moths as an aside, but nary a tome was dedicated entirely to moths, the far larger portion of Lepidoptera. An internet search for popular scientific literature about moths also yielded slim results. Considering the staggering diversity and beauty of many moths, I was surprised to find that few nerds had written book length (or even magazine article length) love letters to these critters.
Order Lepodiptera is made up of butterflies and moths; butterflies are often day-flying and brightly colored, which is probably why the amount of attention paid to them seems skewed when compared to the brain melting variety of moths. Within Lepidoptera, butterflies are contained in two superfamilies: Papilionoidea (true butterflies) and Hesperioidea (skippers). The remaining 42 superfamilies are all moths! About 6,000 moth species of can be found in California alone, compared to approximately 500 species of butterflies in our fair state. Moths in Oakland can be as innocuous as the tiny specks that try to fly up your nose on warm nights, or hummingbird-sized wraiths colored like storm clouds at sunset. With that much diversity, where does one even start to understand basic identification?
Fortunately, Ken-ichi Ueda, amateur lepidopterist and moth enthusiast, was willing to help initiate newbies such as myself to the basics of moth identification. We had our Wild Oakland moth walk in Knowland Park on a warm October evening- Fall in the temperate Bay Area is the best time to find these (usually) nocturnal flyers.
Meeting a half hour before sunset, we found a good spot to set our light traps to lure our quarry. The traps consisted of a rope tied between two trees, a white sheet clipped to the rope, and an ultra-violet light hanging over the sheet. The moths are lured to the light and then land on the sheet, where they often stay motionless long enough to photograph or take a good look at them.
While we waited for the sun to set, Ken-ichi answered questions about moth natural history and identification.
“Why are moths attracted to light?”
No one really knows. There’s a theory that moths navigate by the light of the moon- if they keep the moon at a certain angle, they can fly in a straight line. If there’s a light source nearer to them, they’ll get confused and start to fly in circles around it.
“How do moths avoid getting eaten by predators?”
Oooh, another question that gets a lepidopterist’s heart pumping faster. Bats are the primary predator of night-flying moths; some moths can emit high-frequency sounds that might confuse a bats’ echolocation, but the sound might also advertise that a moth tastes disgusting and warn away any bat that hears it. Additionally, day-flying moths can mimic unpalatable insects like wasps, mimic toxic butterflies like pipevine swallowtails, or be toxic themselves.
“What are the differences between moths and butterflies?”
Fuzzy bodies, fuzzy antennae, and they fly at night, right? Response: Sometimes, sometimes, and sometimes. Generally speaking, butterflies have thin antennae with club-like tips and fly during the day, while moths have furrier antennae with no club on the tip, fly at night, and have fuzzier bodies to trap heat as the sun goes down. But like everything else in nature, there are many exceptions; there are brightly colored day-flying moths and drab night-flying butterflies.
Some lepidopterists claim that all butterflies are actually day-flying moths, while others maintain that butterflies and moths are more distinct. Evolutionarily speaking, all the important moth families were around by the time the first butterflies appeared; the oldest butterfly fossil is about 55 million years old, whereas primitive moths are estimated to have appeared about 195 million years ago.
Since moths are so diverse, Ken-ichi’s lesson for the evening was teaching us the differences between the two of the largest superfamilies of moths we were most likely to see- Geometroidea (geometrids) and Noctuoidea (noctuids). When at rest, geometrids look flat because they hold their wings horizontally and have slim abdomens, whereas noctuids “stick up” more because of their fatter abdomens; they also look like they’re wearing a “hairy vest” on their thorax. Of course there are exceptions and similarities galore across species, but if you ever want to impress someone with your knowledge of moths just start saying “geometrid” and “noctuid” a lot.
As it got darker, moths started to fly to the light trap and we saw some gorgeous species like the lichen moth and the gold striped filbertworm moth. We didn’t see the large and stunning Edward’s Glassywing that lives in Knowland Park, but rumor has it one needs to stay out ’till the wee hours of the morning for this moth to make an appearance. Let me know if you see one!