Sometimes life comes at you in unexpected ways; such was the case this fall, on a trip to Myles Standish State Forest in Plymouth, MA. I had just finished examining a nice female Chinese mantis (Tenodera parasinensis) sitting on a telephone pole near the visitor’s center, when I looked up to see a black and white blur approaching me. It looked to be a little smaller than my hand and flying rapidly and erratically. Having just read about this animal online a few days before, I immediately knew what I was looking at, despite not actually being able to see it. “Barrens buckmoth!”, I yelled, to no one in particular. The fluttering form zipped overhead and whizzed off down the trail. No way was I going to pursue; when a bug like that is on a mission, one dares not intervene.
Buck moths (genus Hemileuca) are medium-to-large saturniid moths widespread in the U.S. Many are fall-emerging insects, with the caterpillars growing up during the spring and summer, pupating, and emerging as adults in autumn. Caterpillars are capable of inflicting a powerful sting. There are 23 species, all variously patterned in black and white, or sometimes with splashes of other colors. Only 2 of those species make it into the northeastern U.S. One, Hemileuca lucina, is actually a New England specialty, having only been found in parts of Maine, New Hampshire, and Massachusetts. It is usually found in wet, boggy meadows, where its principal host, Spirea alba (white meadowsweet) occurs. As caterpillars mature, they tend to disperse and feed on numerous other plants before pupating. The other species, Hemileuca maia, is distributed more widely across the eastern states, but is rare in the northern part of its range. In New England it is restricted to pine-oak barrens, where its sole host is scrub oak (Quercus ilicifolia). Farther south it gains an additional host, live oak (Quercus virginiana), which is a common southern tree. Here the Buckmoth is sometimes considered a pest, a far cry from its status in my neck of the woods.
Prior to this year, I had only ever seen one individual of the genus: a good-sized H. lucina caterpillar that I had found feeding on Spirea at the edge of a salt marsh in Maine. Ordinarily I would have reared it to adulthood after photographing it, but this was only a few days before I left for Gorongosa, Mozambique, and I knew the caterpillar would die if I left it alone for several weeks. I ended up returning the animal to his home. After I returned from Mozambique, I had no time to check that area for adults before I headed off to begin college in Ithaca, a place where no buckmoths are known to live. In the past two years I haven’t been anywhere near a good buckmoth locality and the idea of seeing them faded from my mind. This October, however, I was in New England again, and one day while gathering food for a pet praying mantis, I came across a big adult buckmoth stumbling along a boardwalk in a powerline right-of-way! There was lots of Spirea present, and a little research later led me to conclude that this was also H. lucina.
The story picks up again about a week later at Myles Standish, site of my first encounter with a healthy adult buckmoth. This state forest is a huge pine-oak barren, so I figured these had to be H. maia (some later research confirmed that H. lucina is absent here, while H. maia is relatively abundant). I didn’t expect to be able to catch or photograph any, given my first sighting. Throughout the day I continued to see them from time to time, always flying overhead, weaving swiftly through the pine branches. Towards the end of my visit I made a quick foray into a grassy area to listen for any interesting katydids. Suddenly a black and white form in front of me caught my eye. I stopped short. There was a buckmoth, a beautiful H. maia, just sitting on a grass stem! I ever-so-carefully set down my backpack, grabbed my camera, and inched forward for some photos. Luckily the moth seemed pretty oblivious to my presence, so I was able to get a few nice shots. Quite nice to be able to see both northeastern species of buckmoths within 2 weeks!