Moth Goggles

Eighty-nine percent of the order Lepidoptera is moths, and yet the other eleven percent, butterflies, seem to get all the love. In this series, two Bay Area enthusiasts shine light on why “mothing” deserves its moment.

Part 1: A reflection by Cat Chang.

Pilina: the threads of connection to all that’s nearby

I’m a nature nerd—totally excited to see my favorite plants in bloom, geeking out on miniature gardens of babystars and native clovers or deeply appreciating the grandness of our gnarled oaks outstretched, their limbs seeking the horizon. All my life, plants have been my go-to companions, allowing me to come back to ground. When I was a child, my Hawai’ian grandmother and I would walk clockwise around her home on O’ahu, stopping at each plant to say hello, stroking some of them, paying attention to where the plant was in its phenology: Was it sending out shoots? Flowering? Going into dormancy? Understanding what plant was where in its life meant we knew when to harvest, make leis, cook with or offer it to someone in need. I still do this today in my own yard here in the Bay Area, especially in stressful times. This lifelong connection to the growing things around me has always been a source of inspiration but also a focus of curiosity. 

The more I encounter our Bay Area native plants in their natural habitats, the more my curiosity stirs with questions: Why is this plant here, now? What part does it play with what’s around it? In Hawai’ian: What are its pilina or threads of connection to everything around it? 

Uncovering these threads is fascinating, especially learning how a plant can host insect life. Ten years ago, a couple of lepidopterists—the late UC Berkeley entomologist Jerry Powell and author and artist Liam O’Brien—realized I was game to hang out with them. They were excited to have someone identify the plants encountered on their forays; I was excited to be out in new habitats with fun people. But nothing is ever that simple. Spending time with them meant I was learning about the butterflies and moths they were surveying. It was a deep dive into a whole other order of life.

I imagine most of us think about moths when it’s time to take a sweater out of storage only to find holes in it. Those dang moths! I prefer my sweaters hole-free, and although I’m 100 percent down to banish these moths from my domicile, I’ve come to appreciate that even these species are worth knowing, as are, indeed, the other 4,500 or more moth species calling California home. Not all of them are as pernicious, and in fact some of them challenge the notion there’s a difference between moths and butterflies (other than a familiar human reaction: “yech, moths are gross!” and “butterflies are beautiful!”).

Let’s review what makes a butterfly a butterfly. It’s an insect with six legs, club-shaped antennae, and often wings covered by tiny scales. The scales can be brilliantly colored, arranged in patterns of fantastic stripes, dots, gradients—either in the service of camouflage or, conversely, as a reminder to predators that creatures with such markings can taste very bad. Butterflies fly in the day when temperatures are warm, visiting flowers to feed on nectar, transferring pollen, extracting salts from mud to aid in reproduction, and, as always, looking for mates. They famously metamorphose from caterpillar to pupa to their adult form. 

Moths are almost the same. They have similar physiology, differing mostly in wing shape and posture and antennae form. Many have less brilliant scales, but like butterflies’ the scales are arranged in patterns. Some are day-flying; the vast majority are nocturnal. And moths also transform from larva to pupa to adult. They’re so similar, I sometimes mistake a moth for a butterfly.

Both creatures find their mates by sensing pheromones. But unlike butterflies, which exchange pheromones at short ranges, many male moths, using their antennae, can detect females from miles away; smell is a necessary advantage for night-flying creatures. When looking up close at moths, I marvel at the variety of antennae: some have bristly leaf shapes, others are feather-like, and some are tucked in under the wings, almost modest. 

Together, moths and butterflies make up the order Lepidoptera (meaning scaled wing). With more than 89 percent of the order being moths, “moths are really the story,” O’Brien says. Most moths in our Bay Area have evolved with host plant relationships. Indeed, without the plant species present, the moth can’t be present. Understanding these relationships brings me joy when I see the moth with the plant. Calscape, a project of the California Native Plant Society, is a great resource for learning which plants host which moths and butterflies. Should you discover a favorite moth, you can create habitat for it by planting the host and other nectar-providing plants, just like a butterfly garden. Within my own garden, a cloud of mint moths flutter up from my mint as I come through the gate. Their scales are a bright brick-red over orange in an intricate pattern. Neoterpes edwardsata, a beautiful creamy-hued geometrid moth marked with a heavy brown band, will fly up from my California poppies. The moth-eating birds have a field day every day in my yard. Moths are as important to supporting an ecosystem as butterflies.

Epilogue

While I’m not including our hole-making bandits in our short list of moth tourism, here’s a little tribute to them. There are two culprit species in abundance in our area—the webbing clothes moth and the case-bearing clothes moth. They likely have been around since prehistoric times, having traveled the world with us humans. They eat keratin and do not limit their appetite to wool goods, also enjoying feathers, fur, silk. 

The larva of the webbing clothes moth makes a silken cocoon, nestling into the fibers of a garment or rug. The adults are rarely seen as they hide in dark places. The case-bearing clothes moth is more adventurous. I find their larval cases—roughly the same size as a basmati rice grain and oddly deflated if there’s no inhabitant—made from fibers they’ve harvested. Late moth expert and entomologist Jerry Powell noted that these cases are “sometimes blends of many colors, depending on the richness of the scarves and sweaters they have encountered.” But if you discover one with a larva inside, watch how it emerges and then pulls its case forward, ensconcing the larva entirely in its home again. The deliberate movement is reminiscent of an inchworm (which is the moth larva in the Geometridae family).

—Cat Chang