Moths drawn to lights, rotten beer, often against their best interests

Lawyer and moth-er (as in moth collector) Harry Zirlin has his own special recipe for brewing moth mung, or bait, that he smears on trees like sap.

He uses a bottle of beer, a few bad bananas, Grandma’s Molasses (or a box of brown sugar) and maybe some yeast if he is impatient. “Most people who are rational and objective say that all you need is beer,” he says. “Leave it around for a while.” He painted mung on Central Park trees for 80 moth watchers for a nighttime tour with the Linnean Society of New York.

I was surprised there was such a thing as moth bait, let alone a heated discussion, but he told me to Google it. Sure enough, there are tons of competing moth mung recipes and delivery devices, involving rotting fruit, red plastic plates, suet feeders, rum and sponges.

Moth-ing is surprisingly popular, Zirlin says. Unlike birding it doesn’t involve expensive and tedious electronics. He uses mung, a net and a white sheet with a bright white light (preferably black light or mercury vapor). No one is sure why moths are drawn to flames and artificial light, he says. It’s probably a quirk in their senses; they seem to get nothing out of the deal and it makes them easier prey.

Butterflies, by the way, are just a daytime subset of moths. In some languages there’s no difference between the words for moths and butterflies, Zirlin says. The French call moths, papillon de nuit, or butterfly of the night.

The order Lepidoptera has about 10-11 times as many moth species as butterflies–a ratio that generally caries through to specific areas, he says. So if New York City has about 70 butterfly species, it probably has at least 700 moth species.

Someone who watches or collects and pins moths (yes, they still do that) is known as a mother (spelled like mom, but pronounced the other way) or lepidopterist. “Very few lepidopterists I know are exclusivly interested in butterflies,” he says. “The very serious ones are interested in nothing but moths.” That sounds kind of grim and professional.

Different types of moths are attracted in different ways. The showy and popular Monarchs and Swallowtails go to flowers like Buddleia (butterfly bush) or milkweed. The biggest North American moths, like the Prometheus, don’t eat at all; they only have vestigal mouth organs and survive on energy gathered as a caterpillar. Sphinx moths drink from hummingbird feeders. The mung only draws the moths that would normally eat sap on a tree, but, it also lures butterflies during the day.: Question Mark (Polygonia interrogationis) or Eastern Comma (Polygonia comma), Red Admirals.

In New York City, Central Park may be the lamest of the big parks for moth-watching, he says, because so little of it is wild. Van Cortlandt with its Prometheus moths (like the one pictured her from Prospect Park), Pelham Bay with its underwings, just about anything is better–though not necessarily as well-trafficked and safe at night.

Read more about butterfly and moth watching

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