At this time of year we have the opportunity to observe moths not only at our porch lights, but at flowers as well. A number of moths, including the American Ear Moth (Amphipoea americana) shown above, extract nectar from flowers in the light of day. However, most moth species await dusk or dark to come out from their resting places. Nectaring is not a behavior of all moth species. Some, like the famous Luna Moth (Actias luna) and other Giant Silkworm Moths, do not feed at all as adults and therefor have short lives. In Columbia County, we have just a brief period in spring where we may see the week-long-lived Luna Moth at rest in the forest, or by a porch light. Moths’ attraction to light is a bit of a mystery, but it may relate to their use of the moon for orientation. In any case, this attraction has allowed us to study Columbia County moths by using specialized lights to attract a great diversity of them.
The Moth Tally
One would think that tallying the species of moths in a rural county in upstate New York would be a feasible task. Columbia County is about 650 square miles of land, largely composed of Oak-Hickory and Northern Hardwood (with hemlock and/or pine) forest types. Yes, there are swamps, rocky barrens, shrublands, meadows, farmland and various other habitats; and elevation ranges from about 10 ft. by the Hudson River to over 2,000 ft. at Harvey Mountain; but, it’s just another rural county in upstate New York. How many moth species can this place have?
Well, after two years of simply observing or conducting official moth surveys; asking my girlfriend to spend many a Friday night in the woods or by the house beside a moth light; the answer is that I have no idea. For now, our number is about 560 species of moths in the county (determined with the help of other accredited observers), but give it a week or two, and we may have 600 or more. Nearly every time out mothing, whether it’s a place I have surveyed before or not, I find one, two, or ten new species for our list. With no end to the tally in sight given the continued occurrence of many new species on each outing, I’m excited to see just how big this list will get and what the next survey will bring in.
Being that moths are a very diverse group of insects, it’s no surprise that we apparently are far from determining their diversity in our county. Both moths and butterflies belong to the order Lepidoptera, the second largest insect order. There are about 13,000 species of Lepidoptera in the United States, with roughly 5,000 of them residing east of the Mississippi. New York has a long history of studying moths. In 1916, there were 2,304 documented species of moths statewide. The species list was the work of many observers, including entomologists Edward Doubleday, Augustus R. Grote, and Joseph Lintner, all who made considerable contributions to our knowledge of the state’s Lepidoptera; some 26 other observers throughout the state also contributed. A later estimate put the number at about 3,300 species statewide. Neighboring New York, John Himmelman, author of Discovering Moths, notes Connecticut as having about 2,300 species of moths.
To get an idea of what our total moth diversity might be in Columbia County, we can look at the results of some moth studies from smaller regions. Work at the 318 acre Hunt-Parker Sanctuary in Westchester County, N.Y. documented 450 species of moths from 2002 to 2005. Another study in several northwest Vermont counties used surveying as well as historical records and collections to assess moth diversity. They documented nearly 1,700 species.
Perhaps the most comparable assessment took place in the Ashokan region (the town of Olive, N.Y.) of the Catskill Mountains. The study took place over the course of three summers, from the spring of 1992 to fall of 1994. Instead of looking at the diversity of all moths, the study focused on the Sphinx Moth (Sphingidae) and Owlet Moth (Noctuidae) families. The region is quite close to Columbia County, about 20 miles south west. Elevation there ranges from about 700 ft. to 3,000 ft.; it hosts a large portion of the Ashokan Resevior, but otherwise is well forested with mixed development. The area is about a tenth the size of Columbia County. These researchers documented 358 Owlet Moth species compared to the 146 we have seen in Columbia County. If we make the assumptions that they saw all of the Owlet Moths present, that we have as many such species here in Columbia County, and that the ratio of Owlet Moths to non-Owlet Moths is constant, then we can roughly estimate Columbia County moth diversity at about 1,350 species. That number may be too high, as the Ashokan region hosts a variety of rare plants and has high elevation ecoregions that are absent here. Both of these characteristics may enhance moth diversity. However, that estimate could also be too low, because our study area is 10 times that of the Ashokan region. Either way, it gives us a ball park figure and suggests that we are not even half way there in assessing Columbia County moth diversity.
One difficult aspect of determining moth diversity anywhere is the much overlooked very small moths, called micromoths. Also known as microlepidoptera, these specimens represent a majority of moth species in the United States. The caterpillars of these small moths are unlikely to be seen by the human eye as most are endophagus (they bore into, or are hatched within, a plant’s stem, wood, fruit or leaves); some even feed on dead animals, fungi, or parasitize other insects; others are aquatic, feeding on algae in streams or waterlily in ponds and lakes. Because of their small size, there is relatively little known about micromoths. There may be undescribed species of them here in New York State, or even within Columbia County. We have seen a great number of these small creatures during our surveys, and we do our best to document them, but, even with the help of macro photography, it seems impossible to identify many of them due to their size and the limited identification resources.
I have to admit, before I was introduced to mothing by wildlife biologist Conrad Vispo, I knew of three types of moths: the Luna Moth, the clothes moths (the ones you fend off with moths balls) and the ‘none of the above’, which were, in my mind, all gray and nondescript. It took only a survey for me to discover their beauty and diversity. There are endless colors, shapes, and textures; although all moths are covered by scales (Lepidoptera is Latin for “scale wing”), some appear to be fury while others are smooth and glossy. Some moths have patterns that are so artistic and unique that it is hard to imagine the evolutionary paths that made them. Our program has done some mothing with students, and they have made up their own names for some species we’ve seen, including the “Dragon Moth”, the “Jet Fighter”, and the “Strawberry-lemonade Moth”.
The County’s Rare Moths
There are moth species that we see in great abundances during our surveys, like the Tent Caterpillar Moth (Malacosoma sp.; there are in fact two species in our region) and the Common Idia (Idea aemula), whose caterpillars feed on dead leaves. On the other hand, there are rare moths here as well. A moth may be rare because their larval host plant is uncommon. In the case of the Barred Granite (Speranza subcessaria), an uncommon moth here, their host plants, Gooseberry and Currant, were deliberately removed from our landscape during the early 20th century. These plants were a threat to lumber production because they were an intermediate host of a disease that affected White Pine, a once economically important tree in Columbia County. Other factors, such as environmental pressures caused by pesticides, light pollution, development, invasive species, or deer herbivory, may negatively affect a moth species and contribute to its rarity. A third possibility is that a moth species is simply difficult to survey for and is therefore seldom noticed. For example, I have seen a number of Tomato Hornworm caterpillars in our garden, but I have never seen its adult form (the Five-spotted Sphinx Moth), even though I survey for moths around my home regularly.
Below are a few examples of Columbia County’s rare moths. In our many surveys, we have seen these species just once.
The Sphinx Moths
Sphingidae, commonly referred to as Sphinx Moths, is just one of many moth families; their species in our region represent only a small fraction (less than 4%) of our moth diversity. However, Sphinx Moths are conspicuous creatures. They are large, often strikingly colored or shaped; many species nectar from flowers and are able to hover in place, giving them common names like “hawk moths” and “hummingbird moths”. There are diurnal, crepuscular (active at dusk and dawn) and nocturnal species in our region. At 1,400 species worldwide, they are one of the best studied groups of insects in the world, partly due to their large size. In the northeastern U.S., there are nearly 40 Sphinx Moth species, of which we’ve documented 20 in Columbia County; with three subfamilies, two of them—commonly referred to as the Large Sphinx Moths (Sphinginae) and the Small Sphinx Moths (Macroglossinae)—are regular visitors to tubular flowers and can be seen nectaring during the day or at dusk. A third subfamily in our region, the Eyed Sphinx Moths (Smerinthinae), have scalloped wings and robust bodies; on their hind wings, most species have blue-filled circular spots resembling eyes.
Members of this group host the longest probosces (a tubular mouthpart used for feeding) of any moth or butterfly in the world. In 1862, after observing Madagascar’s large Star Orchid (Angraecum sesquipedal), Charles Darwin wrote, “In Madagascar there must be moths with probosces capable of extension to a length of between ten and eleven inches”. Darwin’s prediction was verified some 20 years after his death, when a very large Sphinx Moth, Xanthopan morganii praedicta (sometimes referred to as Darwin’s Moth), was discovered in Madagascar; it had a foot-long proboscis that pollinated the orchid’s lengthy nectar spur. The interaction between this strange orchid and its unique pollinator has become a classic example of coevolution; both specimens have reciprocally affected each other’s evolution and now rely on one another to survive.
Although there are no Sphinx Moths in our region that could pollinate such a flower, I have seen a Pawpaw Sphinx (Dolba hyloeus) in Austerlitz, N.Y. nectaring with a roughly 40mm long proboscis; impressive, but hardly comparable to that of Darwin’s moth.
Attracting Sphinx Moths
A great way to attract certain Sphinx Moths is by providing their sought-after flowers in your garden or around your home. In my experience, the hands-down favorite native flower of a number of Sphinx Moths is Monarda fistula, commonly called Wild Bergamot, or Bee Balm. It’s native to every state in the contiguous U.S. except California and Florida, and the flower is also a favorite of many butterflies and other pollinators. The plant seems to prefer well-drained soils and a good amount of sun. If conditions are right and there is a good pulse of flowering, these Monarda patches can be incredibly active with Lepidopterans, including Sphinx Moths; depending on the species, one can observe them nectaring during the day or at dusk. Sphinx Moths like the Hummingbird Clearwing (Hyles thysbe), Snowberry Clearwing and Gallium Sphinx (Hyles gallii) will frequently visit Monarda in daylight hours. Other species, including the Pawpaw Sphinx (Dolba hyloeus), the Laurel Sphinx, and other large and small Sphinx Moths, can be seen nectaring these flowers at dusk. Small amounts of fresh manure will also attract some Sphinx Moths; they will consume liquids from the manure and extract the salts and amino acids.
Entomologists who have been studying and observing moths for decades in the northeastern U.S. and southeastern Canada unanimously agree that populations of the large-sized moths, including Sphinx and Giant Silkworm Moths, are collapsing. Species once present or even abundant just decades ago are now reduced or even absent from locales observed. There are various pressures that collectively are causing this decline, such as excessive deer drowsing, habitat destruction, climate change, light pollution, reduction of early successional habitats and other anthropogenic influences.
The decline of Sphinx and Giant Silkworm Moths has been occurring for a long time in the Northeast. In 1906, decades after the invasion of the nonnative and destructive (responsible for mass tree defoliation/mortality) Gypsy Moth (Lymantria dispar), a parasitic Tachinid fly native to Europe was intentionally introduced in our region. This fly then parasitized caterpillars not only of this invasive species of moth, but of a great number of native moth species as well. Because the Gypsy Moth’s caterpillars occur in forests for just a short while, during the remainder of the year the fly must seek out other caterpillar species to parasitize. Lepidopterists (those that study moths and butterflies) in our region from the 1950s to the 1970s witnessed firsthand the rapid decline of Giant Silkworm Moths and a number of species of Sphinx Moths due to this introduced parasitic fly.
In the 1920s and 30s, Columbia County was on the ‘front-line’ of Gypsy Moth control, many 1000s of pounds of insecticides were sprayed in hopes of managing Gypsy Moth populations. More recently, in the past couple decades, millions of acres of eastern forests have been aerially sprayed with insecticides to suppress Gypsy Moth outbreaks. Because these chemicals specifically affect Lepidoptera larvae, this spraying has had lethal impacts on various species of moth and butterfly caterpillars and is a serious threat to rare Lepidoptera in our region.
We can get a glimpse of historical moth abundances by looking at old insect collections. The Farmscape Ecology Program was donated some preserved moths collected from Columbia County in the 1950s. There are several species in the collection that we have not seen here, not in my two years nor during Conrad Vispo’s previous surveying for moths. Two online resources that verify public reports of Lepidoptera sightings also have no reports of these moths in the county. These species include the Tulip-tree Silkworm (Callosamia angulifera), the Great Tiger Moth (Arctia caja), and the White-lined Sphinx (Hyles lineata). How common these moths were in Columbia County some 60 years ago is not known, but it’s a fair assumption that their populations here have either been extirpated or significantly reduced.
The most common Sphinx Moth in our Columbia County surveys by a long shot has been the Waved Sphinx (Ceratomia undulosa). It’s a very large moth (wingspan to 110mm) and has waved markings and some yellow scales throughout its body if you look closely. Their larvae feed primarily on ash trees, which face certain decline as the recently introduced Emerald Ash Borer infects a higher percentage of ash in our state each year. Although ash makes up only 6-7% of Columbia County’s trees, they are much depended on by a number of Sphinx Moths found in the county, including the Waved Sphinx, the Laurel Sphinx, the Twin-spotted Sphinx (Smerinthus jamaicensis), and other Sphinx Moths that may or may not reside here. There is an uncertain future for these moths in Columbia County.
Columbia County, like in much of our region, has a deer problem. Whether in forests, meadows, or un-fenced gardens, it is clear that nearly everything in their reach is being browsed. This browsing is another threat to Columbia County Sphinx Moths, specifically to the Hemaris species, including the Snowberry Clearwing and the Hummingbird Clearwing. Although we see the diurnal adult clearwing moths nectaring at flowers, their caterpillars are dependent upon various woody and herbaceous plants of forests and meadows, including Viburnum, Honeysuckle (possibly native and non-native varieties), Hawthorn, and Dogbane. These are all relatively small plants. Because their larval host plants are generally low and easily reached by deer, the Hemaris larvae are more affected by these herbivores than larvae that rely on leaves of trees or taller shrubs.
When a larva’s food plant is stunted or killed by widespread herbivory, or anything for that matter, it reduces or removes a vital resource of that species, preventing the completion their life cycle. A Lepidopteran cannot successfully reproduce without access to its larval food plant, which then must sustain the caterpillar until metamorphosis; only as adults can they reproduce. It is hard to say the degree to which deer herbivory in Columbia County, which does seem excessive in certain habitats, is affecting our resident clearwing Sphinx Moths or other Lepidopterans that rely on low plants frequently browsed by deer. NatureServe, a network that assesses the conservation needs of western hemisphere species, notes that deer herbivory when in excess is a serious threat to both the Hummingbird and Snowberry Clearwing. The organization reports other pervasive threats, including herbicides and invasive plants that reduce the abundance of Viburnums and other larvae food plants relied on by these species.
If you are interested in learning more about Columbia County moths, visit our webpage for a photographic list that we are frequently adding to. We would greatly appreciate hearing from any readers in our region who would like to share historical observations or collections (not for our keeping of course) of moths or butterflies from our area. Additionally, if you have any current observations that you’d like to share, or any questions, please contact me (firstname.lastname@example.org). Below, I have listed some moth field guides for our region that are relatively inexpensive and are great resources for species identification and further reading.
Ardetti, J., Elliott, J., Kitching, I.J. & Wasserthal, L.T. (2012). ‘Good Heavens what insect can suck it’ – Charles Darwin, Angraecum sesquipedale and Xanthopan morganii praedicta. Botanical Journal of the Linnean Society. 169 403-42.
New York Department of Environmental Conservation. New York State Ash (Fraxinus spp.) Distribution: Percentage of Ash per Basal Area per County [Map]. <http://www.dec.ny.gov/animals/71542.html> (accessed August 13, 2016).
Himmelman, J. (2002). Discovering Moths: Nighttime Jewels in Your Own Backyard. Camden: Down East Books.
Kawahara, A.Y., Mignault, A.A., Regier, J.C., Kitching, I.J., Mitter, C. (2009). Phylogeny and Biogeography of Hawkmoths (Lepidoptera: Sphingidae): Evidence from Five Nuclear Genes. PloS One,. 4(5), e5719.
Schweitzer, D.F., Minno, M.C., Wagner, D.L. (2011). Rare, Declining, and Poorly Known Butterflies and Moths (Lepidoptera) of Forests and Woodlands in the Eastern United States. U.S. Forest Service, Forest Health Technology Enterprise Team, FHTET-2011-01.
Vispo, C.R. (2014). The Nature of the Place. Hillsdale: Adonis Press.
Wagner, D.L. (2005). Caterpillars of Eastern North America. Princeton: Princeton University Press.
Wagner, D.L. (2012). Moth Decline in Northeastern United States. News of the Lepidopterist’s Society, 54(2), 52-56.
Moth and Caterpillar Guide Books for Our Region
Peterson Field Guide to Moths of Northeastern North America
This guide book by David Beadle and Seabrooke Leckie is an excellent resource for getting to know moths. It includes additional information for each species, including range, if it’s common or uncommon, and the larval food plant.
Caterpillars of Eastern North American
David L. Wagner’s caterpillar guide is an essential tool if you’re hoping to identify caterpillars you see in our region. If you know what kind of plant the caterpillar was on, this guide’s food plant index makes identification very easy.
Additional Online Resources