Moths are Pretty Too!

Butterflies are so well loved – we put them on jewelry and greeting cards. Meanwhile, their moth relatives are underappreciated and even disliked. In a recent survey, 75% of respondents had negative views of moths, replying that they eat clothes, are pests, or are just plain DULL. But there are lots of beautiful moths, including many daytime fliers – so how could that be??! Turns out, when people see a beautiful moth, they misidentify it as a butterfly!

Moths are Pretty.

Moths can be found in every color, size, and shape. And why not, they’re so many! Across the US there’s an estimated 12,000 moth species (835 for butterflies). Camouflage is critical for easy hiding in tree trunks, leaf litter, and the plant understory. Their amazing patterns and colors support hiding. And yes, some moths are dull, helping them blend in as bark, twigs or rocks. Others have features like bright colors, “eyes” that wink, and tails that scare predators. Some don’t look like typical moths, but instead mimic wasps, bees, hummingbirds, bird poop, or inanimate objects.

How to tell a butterfly from a moth?

The easiest differentiator is the antennae. Moths have highly variable antennae shapes ranging from thin and straight to long, curved and “feathery.” But all lack a particular feature of butterflies—a club or hook (skippers) at the end of a stalked antenna. If it’s flying at night, it’s probably a moth. During the day or dusk it could be either.

Like butterflies, moths undergo complete metamorphosis. Their adult lives are relatively short compared to their other stages – egg, caterpillar, and pupa (called a cocoon for moths). This complete cycle is a generation. Some species have a single generation each year, while others have many.

Here are some of the moths out during the day that don’t look like moths:

Moths are Important Ecologically.

Aside from being a great food source for other wildlife (mostly as caterpillars), many adults are wonderful pollinators. While some moths are out during the day, they’re usually misidentified as wasps (that some of them mimic) or assumed to be butterflies. Observing moths pollinating at night is challenging, but as an example, I have documented 60 species of moths feeding on our summersweet shrub (Clethra alnifolia) alone. That’s more species than all the butterfly species we have ever observed in our yard. Some plants, particularly orchids, rely on moths exclusively for pollination. While some moth species sip nectar and consequently pollinate plants, other food sources include tree sap, honeydew, rotting fruit, and bird or mammal excrement. Some adult moths live such short lives, they don’t feed, or even have mouth parts! Instead, their plant-eating caterpillar stage does all of the eating.

Moths are a good environmental indicator group with importance as a food source for other wildlife. Many populations of moths are found exclusively in specialized ecosystems, dependently linked to the success of specific native plants. This makes them particularly sensitive to changes, including habitat loss and climate change.

As creatures of the night, moths are more numerous and diverse than we perceive. While Pennsylvania lacks any scientific group to oversee lepidoptera, we’re fortunate to have a strong community science effort that documents moth records by county in Butterflies and Moths of North America (BAMONA). Current moth species listed for the state are 2287 species (compared to 162 for butterflies). Moth species are even undercounted, since many species require DNA or microscopic review instead of visual identification.

Nocturnal moths rely on patterns, often to hide from predators during the day. Here’s a sample of some amazing moth patterns:

Conservation.

As you can likely guess, moth populations are declining for the same reasons as other wildlife – habitat loss, pesticide use, and climate change. But moths have an extra challenge – the loss of dark night skies. For millions of years, wildlife has evolved with light (solar) and dark (lunar) cycles that have daily and seasonal variation. At the beginning of the 20th century, artificial light at night (ALAN) started to disrupt the natural light cycles.

Why are moths attracted to light? Guesses include that artificial lights seem like daylight or the moon. By night, some moths are believed to navigate (migration or dispersal) by the brightest object in the sky. Because a street light or a light at your front door will look brighter than the moon, moths can incorrectly perceive those lights to indicate daytime. The result is that the moth will rest or sleep motionless during the night instead of fulfilling its life cycle reproduction role. Complicating the understanding of ALAN is that both light intensity and spectral distribution matter. And of course, humans are making continual changes to our types of external lights, as well as increasing our usage both in currently lit locations and expanding into previously dark geographies.

Nocturnal moths are believed to be impacted by ALAN throughout their lifecycle in many ways. The most significant include reduced reproduction from disturbed mating, increased predation of adults and caterpillars, and decreased dispersal. While most studies suggest ALAN has a negative impact on moths, a few recent studies suggest some positive results, like caterpillars eating for longer periods. There’s much yet to learn.

How We Can Help Moths (& Birds)

• Plant a diverse mix of native plants, the predominant food source for caterpillars. Woody plants are particularly important. Native oak, cherry, and maple trees host hundreds of moth species.
• Leave your leaf “litter.” Many moth species winter in leaves (usually as pupa or caterpillar). A recent study reported a 45% reduction in moth and butterfly abundance when leaves were removed from suburban yards!
• Reduce external light use. Consider using lights that work on motion detectors for safety concerns, and never leave lights on all night.
• Don’t use pesticides. They’re particularly harmful to moths, as caterpillars eat vegetation.

These moths rely on us to Leave the Leaves, as that’s where they overwinter. (So does that beautiful Luna moth and a few others in this post.)

Karen Campbell, a member of Lehigh Valley Audubon and PA Master Naturalist, provided the content and images for this article. Follow Karen on Instagram @kareninnature or visit her website at focusonnatives.com.