Killer moths


Adult female Fulgoraecia exigua – the planthopper parasite moth (Memorial Lake, PA)

When one thinks of moths and their caterpillars, the first image that comes to mind is not of a killer that sucks its victims dry. Indeed, the majority of Lepidoptera are herbivores or detritivores. Some species occasionally resort to cannibalism or scavenging dead or dying insects when starving, but strictly carnivorous caterpillars are few and far between. The ones that exist, however, are pretty striking. Probably the most well-known and exciting are the Hawaiian species of the genus Eupithecia, small inchworms that are sit-and-wait predators of fruit flies. Videos such as this one abound on the internet, and it’s hard not to be impressed by their hunting prowess. Hawaii also hosts the predatory Hyposmocoma pupumoehewa (literally, ‘snail’s nightmare’), which ties down snails with silk, forces its way into the snails’ shells, and eats them. In the continental U.S, the predaceous Lepidoptera are not quite as cinematic, but equally fascinating.

There is a nice article on BugGuide that highlights the meat-eating moths of north america. One charismatic butterfly, the Harvester (Feniseca tarquinius) of the eastern U.S, feeds on wooly aphids as a caterpillar. The larva hangs out in the aphid colonies and munches its way through aphid after aphid. These colonies are usually attended by ants, who feed on the honeydew produced by the aphids and in theory are supposed to protect the aphids from predators – obviously they fail to do their job when Feniseca is involved. I first heard about this insect when I was in elementary school and I was told of an aphid colony in Holden, ME, where the Harvester was reported to frequent, but I never found it there. Years passed before I finally found a single adult sitting on a building on Cornell’s campus in Ithaca, NY. I have yet to see the caterpillar…


The Harvester (Feniseca tarquinius) from Ithaca, NY. A very innocent-looking butterfly, given the aphids it destroyed as a caterpillar. 

But among all these strange lepidopterans, one group stands out. The family Epipyropidae, with only 32 species worldwide, is fully parasitic on true bugs, mostly planthoppers but with at least one species, Epipomponia nawai, parasitizing large cicadas (see here for a fantastic photo of this). In the U.S. we have but one species, Fulgoraecia exigua, usually called the planthopper parasite moth. It ranges from southern NY to FL, west to CA, and has been found parasitizing many different planthopper species. The eggs are laid on plants, and the first instar caterpillars locate and attach to a planthopper, feeding on its bodily fluids for the rest of its days. The moth is a drab gray triangle that sometimes arrives at lights.

Fulgoraecia exigua cocoon (Owings Mills, MD)

I have run across this odd animal on two occasions. In Maryland (2014), I came across several Fulgoraecia cocoons, which are immediately recognizable because they look like the Sydney Opera House (seriously!). I wanted to collect one to rear out the moth, but I feared I’d destroy the cocoons if I tried to detach them from the substrate, so I left them alone. Last fall (2017), I was beating shrubbery in Lebanon county, PA, when I noticed a planthopper Metcalfa pruinosa in my net that looked a little woozy. Upon closer inspectionI found a Fulgoraecia larva attached to the hopper’s abdomen! Unfortunately by the time I got around to photographing it, the caterpillar had already dropped off the (now deceased) planthopper and spun its cocoon, so I was unable to photograph the parasitic behavior. Two weeks later, the adult moth emerged and I was finally able to at least get a shot of that life stage. Hopefully someday I’ll be lucky enough to photograph the caterpillar parasitizing a planthopper.


Empty cocoon and extruded pupal case of the Fulgoraecia adult in the first photo of this post. A small clutch of eggs (infertile) laid by the moth can be seen on the right. 


Black-and-white wonders


Barrens buckmoth (Hemileuca maia) in pine-oak barrens habitat (Plymouth, MA)

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.


Hemileuca lucina caterpillar (Scarborough, ME)

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.


New England Buckmoth (Hemileuca lucina) found in Rochester, NH

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!


Hemileuca maia is generally darker colored than H. lucina, with more well-defined black and white bands.

Rearing North America’s largest moth


Caterpillar of the cecropia moth, Hyalophora cecropia (Kennebunk, ME)

Almost immediately after finding the northeast’s rarest waterscorpion, my dad alerted me to a “really cool caterpillar” just a few steps away. When he pointed it out to me I was stunned–a cecropia moth caterpillar! An iconic species, Hyalophora cecropia is considered to be the largest moth in North America, with an equally large caterpillar. But they are not just large–they are absolutely beautiful in all stages. Caterpillars are plump green monsters bristling with red, yellow, and blue scoli (knobs with spikes), and the adults are an unbelievable mixture of reds, browns, pinks, and creams, one of the most charismatic moths out there and a perfect example to point to when people say that moths aren’t as beautiful as butterflies. I had only seen three adults in my life and never a caterpillar, so I was pretty dang excited about this one.


The resulting moth.

After I had taken the caterpillar home and photographed it, I set up an enclosure with lots of food. The ‘pillar was originally on speckled alder, but I found that it would accept maple as well. The next day the leaves were gone, converted into a pile of frass at the bottom of the container, as any self-respecting caterpillar tends to do. This continued for several weeks, with daily replacing of the food and emptying of the waste a necessity for the caterpillar’s survival. Strange as this may sound, I found the frass pellets to be little works of art, intricately marked with lines and spots. Unfortunately I never thought to take a photo. Eventually the caterpillar pupated in a huge baggy cocoon, and into the garage it went to overwinter.


What a wondrous sight to wake up to!

One lovely day next June, I found that the adult moth had emerged. The first thing I did upon seeing her hanging upside down in the rearing cage might seem a bit odd: I bent down and sniffed her. Something I have experienced with every cecropia moth I have encountered is that they smell very strongly of peanut butter! I initially thought this was just the female’s pheromones, but I have smelled it on males as well. It was a miracle that the caterpillar had not been parasitized by flies or wasps, as many such large caterpillars often are. My moth was a female, as evidenced by her plump abdomen full of eggs and her slender antennae (males have large feathery antennae to detect the pheromones of the female). Cecropia moth adults have no functional mouthparts and only live long enough to reproduce, so the next day my dad and I took her back to where we found the caterpillar and released her deep in the bushes, where she hopefully attracted a male and laid eggs to bring about the next generation of these spectacular insects.


Detail of the abdomen.

Various shots from Gorongosa

A few photos from the past few days of several of the more spectacular animals found in Gorongosa National Park, in no particular order.


A beautiful grasshopper Acrida acuminata, about the length of my hand.


Enormous carabid beetle Thermophilum sp, with my index finger for scale.


Nymph of the Precious Sibyll Mantis, Sibylla pretiosa. One of the oddest looking mantids out there, and one of my favorites. 


A gorgeous day-flying noctuid moth, Egybolis vaillantina.


Something a little larger – an adult male Impala (Aepyceros melampus) at the edge of the miombo forest. Not what I usually shoot, but definitely fun to see. 

Synanthedon acerni


A maple callus borer (Synanthedon acerni) at a light (Kennebunk, ME). The pale orange moth above it is a Northern pine looper (Caripeta piniata).

For my first post, I want to quickly highlight an interesting little animal that recently came to my porch light. This funny-looking insect with a red tuft at the tip of its abdomen is Synanthedon acerni, the Maple Callus Borer moth. The only member of its family (Sesiidae) to regularly come to lights in the eastern United States, its caterpillars bore into maple trees, creating calluses. Despite this, they are not major pests, and are quite cool to look at, with their wasp-mimicking colors and patterns. If you live in the eastern United States or Canada, and have maple trees in your yard, watch for this little moth at your lights on warm June and July nights.


Another Maple Callus Borer (Schoodic Peninsula, ME)

More info on BugGuide.