Quick, name a pollinator! What’s the first thing that popped into your mind? Maybe it was a honeybee. Or maybe native bumblebees and wasps. Possibly even showy butterflies like monarchs and swallowtails, or feathered pollinators like hummingbirds, or warm-blooded pollinators like the lesser long-nosed bat. But are moths anywhere on your list?
If not, they should be! Though these pollinators are active mostly at dusk and at night, and often get the short shrift when compared to their day-flying butterfly cousins, they also play an important role in pollination. More than that, they can be every bit as striking, weird, and wonderful as other pollinators — and you can observe them right in your backyard, if you know what you’re doing. So let’s talk moths for a minute.
THE OTHER LEPIDOPTERA
What exactly are moths? And how can you tell them apart from butterflies? They’re insects in the order Lepidoptera, and like butterflies, they’ve got scaly wings, antenna, and a hankering for flower nectar. They also have a similar life cycle. Moths start out as eggs that hatch into caterpillars and spend all their time eating food — mostly leaves, though some moths love to feast on wool and silk. Once the caterpillars are grown, they form cocoons, and eventually metamorphose into their winged adult stage. That’s when some species of moths take on the role of pollinators.
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Keep in mind that “moth” isn’t as clear-cut a group as butterflies — “moth” is kind of a catch-all term for any Lepidopteran that’s not a butterfly. In fact, butterflies only make up 10% of all ~180,000 known Lepidoptera! Here’s a quick list of things to look for if you’ve got a bug on hand and want to know if it’s a butterfly or moth (though none of these are always going to work):
- Antenna: Do its antenna have clubs on the end? If not — if they’re just straight, and especially if they’re feathery — it’s a moth.
- Wings: Is it holding its wings flat or upright while sitting still? If it’s holding them flat, it’s probably a moth.
- Time of day: Is it dark out? If it’s after sunset, it’s probably a moth. That being said, some moths can be active during the day, and some butterflies are around in the early evening.
- General weirdness: Since “moths” isn’t a united taxonomic group, there’s some moths that just look plain weird! Plume moths, for example, have narrow wings that don’t really look like what you’d expect from a butterfly or moth.
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SECRET POLLINATORS
So how important are moths as pollinators? The things is, we still don’t really know. Biologists interested in pollination tend to focus on those that are out and about during the day, so there’s been a lot more research done on pollinators like honeybees and butterflies than on moths. That’s not to say that there aren’t researchers working to change that! Here’s what we know so far. Unlike honeybees, moths probably aren’t directly important to crop pollination. There’s some notable exceptions, though — one study found, for example, that moth pollinators may be playing a larger role in setting cloudberries and blueberries than we previously thought. More than that, just because moths aren’t themselves pollinating crop plants doesn’t mean they’re not important to crops. In agricultural landscapes, pollinators that are mostly visiting wildflowers and weeds around the edges of fields can still benefit crops by increasing the local biodiversity, and supplementing honeybee populations. There’s recent evidence suggesting that moths may be doing the same thing. They might not be visiting as many flowers as honeybees do, but they visit a lot more different ones, and in the end that’s good for agriculture, too.
If you zoom out a bit more, moths are crucial in maintaining native biodiversity. Biodiversity all over the world is under threat from habitat loss, climate change, and pollution, and pollinator-plant relationships are more important than ever. A lot of moths are specialized pollinators that have mutualistic relationships with specific plants. In the Midwest, there’s the endangered western prairie fringed orchid, which depends on hawkmoths for pollination; in the Southwest, sphinx moths and hawk moths pollinate yucca plants. We don’t really have a good idea of how much and how frequently moths are carrying pollen in most ecosystems — different studies have found that anywhere from 10% to 76% of moths studied were carrying pollen. What we do know is that they’re probably more important than we’ve realized.
BACKYARD MOTHS
Moths are incredibly diverse and important pollinators. And if you’ve become convinced that they’re important and fascinating, you’re in luck — you don’t have to go beyond your backyard to find moths! While summer is the best time for observing them, they’re around for as long as temperatures are above freezing. To observe them, you really just need a dark backyard, a porch light, and a white sheet (so they’ve got somewhere to settle). If you want to get fancy, you could point a flashlight (or a blacklight, if you’ve got protective eyewear) at the sheet instead. Sooner or later, moths will start coming by.
Want to know what moth you’ve found? Consider snapping a photo and making an account on iNaturalist, where other citizen scientists can identify your moth for you, and your observation can become part of a database used by biologists to document biodiversity. Or submit it to a website dedicated specifically to invertebrates, like Bug Guide.
Want to make your backyard more moth-friendly? Try using fewer pesticides and planting more natives — just like butterflies and native bees, moths benefit from fewer pesticides and more native plants; many beautiful varieties are available for any Pennsylvania garden, from red columbines to Virginia bluebells to showy goldenrod. Also consider leaving leaf litter and debris on the ground, since that’s where moth larva spend the coldest months of the winter. And if you don’t have a backyard to refurbish, moths — like other native insects — could use your help in other ways. If you have the means, you can donate to organizations like the Xerces Society or Butterflies and Moths of North America, which are working to ensure that moths and other native pollinators are still around in the future.
Related POP Resources:
POP Plants & The Pollinators They Attract
https://www.phillyorchards.org/2020/08/05/on-the-wings-of-dragonflies-observational-ecology-practices-for-students-of-all-ages-pdf-lesson-pack-download/
https://www.phillyorchards.org/2015/05/13/beneficial-insect-releases-for-orchards/
https://www.phillyorchards.org/2019/07/15/expert-interview-howard-goldstein-on-building-a-pollinator-friendly-habitat/
Outside Resources:
https://xerces.org/
https://extension.psu.edu/pennsylvania-native-plants-for-the-perennial-garden
https://bugguide.net/node/view/15740
http://www.mothscount.org/text/18/FAQs_and_myths.html
https://www.si.edu/spotlight/buginfo/moths
https://link.springer.com/article/10.1007/s11829-016-9414-3
https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2019.0877#RSBL20190877C37
https://www.humanegardener.com/night-beauties-4-ways-help-moths-garden/
http://nationalmothweek.org/finding-moths-2/
This blog post was researched and written by Daria Syskine.
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