Friday, August 26, 2016

Moth Mania

The last full week of July was National Moth Week, and I'm finally getting around to posting about mine. I did moth programs this year and last, and I'll be sharing photos of moths from both events, plus some of moths that I've found at my porch light at night, or just wherever. But first, I will obviously have to educate you non-moth-ers about moths and why they rule. (If you already know why moths rule, feel free to jump ahead.)

Butterflies get all the attention. They're pretty, and they fly during the day when us fellow day-dwellers are likely to actually see them. Moths, on the other hand, are mostly nocturnal and often drab by comparison. But there are way more moths than butterflies, and many are just as stunning as their butterfly brethren. Moths and butterflies are really two sides of the same coin. There isn't even a hard and fast rule to separate them, but here is an infographic I made to provide some general guidelines.

Of those rules, the one about the antennae is most reliable. Butterflies have thin, filamentous antennae that are club-shaped at the end, while moth antennae are feathery or filamentous and unclubbed. The only exception to this rule that I know of in North America north of Mexico is the genus Hemaris, also known as hummingbird moths. Fortunately, they are very distinctive.

A hummingbird clearwing, Hemaris thysbe, nectars on
wild bergamot, Monarda fistulosa. Moths in this genus have
clubbed antennae and are active during the day.

The pollination services of moths are invaluable. We think of butterflies as important pollinators, but consider this: there are at least eight species of moth for every species of butterfly. Many plants are pollinated only by certain moths with which they have co-evolved. My favorite example of this is Darwin's orchid and Morgan's sphinx moth. Charles Darwin was studying insect pollination in January 1862 when he received a package containing his namesake orchid.

Darwin's orchid, Angraecum sesquipedale
Photo by Brian [license]

Seeing the foot-long spur that forms the nectary of each flower, Darwin remarked, "Good heavens, what insect can suck it?" He then surmised the orchid was pollinated by an undiscovered moth with a proboscis of unprecedented length. That moth is Morgan's sphinx moth, but it was not discovered until 21 years after Darwin's death. Today, this postulated pollinator has become one of the celebrated predictions of evolution.

Morgan's sphinx moth, Xanthopan morganii
Photo by Esculapio [license]

Moths also serve as an important food source for countless animals, including bats, birds, and spiders. Silk moth caterpillars produce over 140,000 tons of silk each year, worth $250 million. And last but not least, to defend against hungry caterpillars, many plants produce chemicals that we use in our everyday lives. One such chemical is the most widely-consumed central nervous system stimulant: caffeine. So, next time you enjoy a nice warm cup of drugs coffee, thank immature moths and butterflies.

Finding moths is easy; you can see dozens of species just by checking your porch light each night. Here are a few moths I found by doing just that.

Walking across any lawn in the summer is likely to flush small grayish or brownish moths that fly a short distance and then dart back into the grass. At rest, they look like very short sticks. They are the grass-veneers, and not all of them are drab. Some, like this double-banded grass-veneer (Crambus agitatellus), look quite lovely on close inspection.

The barberry geometer, Coryphista meadii, makes brown and black look good.

The large maple spanworm, Prochoerodes lineola, is pleasingly geometrical.

The virgin tiger moth, Grammia virgo, has a straw-like pattern on its forewings that helps it blend in with dry grasses. When disturbed, it flashes its bright hindwings to warn predators it is toxic.

While porch lights do attract plenty of moths, serious moth-ers use additional methods: light trapping and sugar-baiting. Light trapping simply involves hanging a white sheet and illuminating it with ultraviolet or sodium-vapor bulbs.

This is our moth sheet from last summer's Moth Mania program, and I set it up the exact same way this year. The sheet is held up by two beams tied to the back of a park bench, and is illuminated by a black light and our painted turtle's UVB light, because she doesn't need it at night. Here are some of the moths I've found with this method.

The delicate cycnia, Cycnia tenera, is usually seen during the day on or near the blossoms of its host plants, milkweeds and dogbane. It is also called the dogbane tiger moth, and is in the same family as the virgin tiger moth above.

The green leuconycta, Leuconycta diphteroides, becomes nigh invisible during the day by resting among lichens on tree trunks.

This mint-green beauty stole the show last year. It's a green marvel, Acronicta fallax.

And this one took the cake this year. It's a zebra conchylodes, Conchylodes ovulalis.

Sugar-baiting targets moths that are attracted to sap or rotten fruit. It doesn't yield as many moths as light trapping, but it could attract some that your sheet doesn't. The idea is to create a fermented, sugary glop that can be painted on tree trunks (not decks, walls, etc., as it can leave stains). Overripe/rotten fruit and beer/booze are usually used. The mixture I use is peeled baked bananas, flat beer, molasses, brown sugar, and a dash of yeast, aged for a few days to increase in potency. I may make a future post detailing the process, but for now, here are some moths I've baited. 

This black zale, Zale undularis, would have been pretty hard to see if it hadn't been partially sitting on my lovely orange bait. That cryptic coloration is epic.

A Virginia creeper sphinx, Darapsa myron, flutters in front of my bait.

The azalea sphinx, Darapsa choerilus, looks similar to the Virginia creeper sphinx, but note the straight rather than curvy edge between light and dark regions of the wing. This one was found near a baited tree, but for some reason became more enamored with a visitor's shoe.

There are also moths that can be found visiting flowers in the daytime, just like butterflies. I've already mentioned a couple: the hummingbird clearwing and delicate cycnia. But here are a few more.

The chickweed geometer, Haematopis grataria, is probably the most frequently encountered moth in Ohio. You could mistake it for a butterfly as it flutters away from you when you walk across your lawn, but unlike many butterflies, it usually only flies a short distance and then alights.

The ailanthus webworm, Atteva aurea, is actually not native to Ohio, but to South Florida and the tropics. It has spread by adapting tree-of-heaven, an invasive tree from China, as a host plant. It resembles a beetle, which probably makes it less likely to be eaten by predators who have learned that brightly-colored beetles taste bad.

Another moth that is often mistaken for a butterfly is the eight-spotted forester, Alypia octomaculata. But behold the knobless antennae. The black wings with light spots serve as disruptive coloration, making it seem to disappear as it flits through areas of dappled sunlight and shade.

There. If you didn't already appreciate moths, I hope you do now. Moths are easy to find, and never cease to amaze with their endless diversity.

I'll end with a freshly-emerged adult luna moth, Actias luna, that I helped raise from an egg. ^_^


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