Friday, June 21, 2013

Phenology: Buck Moths, in Detail, with Pictures

(Updated in hopes of improving the formatting, but basically the same article posted on Friday.) (And updated again, in honor of its being one of the all-time most visited posts on this web site, with a free link to a blog post that features two other interesting creatures found in Texas, as well as Hemileuca grotei, because it was just a fun read: .)

Here's the summary of what's known about the buck moth family that I promised you (yes, somebody sponsored this). These and Automeris io are the only moths that are unpleasant enough to cause this web site to depart from our usual position, which is that we should learn to live peaceably with most animals including insects.

Unfortunately for readers in Virginia who might want to know whether you've found yet another Hemileuca maia or something that, although equally loathsome, is at least less common, the best documented species other than maia seem to live in the Western States. Several species remain undocumented on the Internet.

They all have a lot in common with Hemileuca maia; moths can be identified by their size and colors as different species, but caterpillars seem to show more individual variation than species identity. Here's the basic buck moth:

Buck Moth - Hemileuca maia
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Here is one of the many ways the caterpillar can look. I've never personally seen one that looked like this, but the photos of these animals on the Internet show lots of color and pattern variation, even among litter mates. Where they live, what they eat, and the weather conditions probably affect the caterpillars' coloring. The identifying feature for Hemileuca caterpillars is that they're large caterpillars with stiff branching spines, each one of which contains about as much venom as a bee sting, so if you inadvertently touch these caterpillars you'll remember it for a week or two.

Buck Moth (Hemileuca maia)
Photo credit: Odephoto">Odephoto
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My method for writing this summary was to begin by perusing Wikipedia,, and Each species name, here presented in alphabetical order, links to a Wikipedia page but the majority of these Wikipedia pages are hypothetical structures lacking species-specific content. and Moth Photographers Group had more photos, but for some of these moths neither even had a filled-in map. had detailed pages for each species found in the Northwestern States and western Canada.

A few observations seem, based on the information I found, to apply to all 23 kinds of Hemileuca:

1. All are most often seen as caterpillars. Young caterpillars have long stiff hairs and are gregarious; older caterpillars have branching, bristling hairs and move out on their own, apparently confident that nothing wants to touch them, much less eat them. Their only predators are smaller insects that can parasitize the caterpillars. Where information was available, all sources agree that all Hemileuca caterpillars are poisonous on contact.

2. Although logging and DDT reduced insect populations to the point where these pest species became rare (and some probably always were just uncommon variant forms of other species), all these caterpillars look to normal observers like something that needs killing. That is because they are. Public-spirited people do not allow these animals to reproduce. If you've never seen one before, you've been lucky...and even if you don't let the first one you see survive, you'll probably see more of them than you could possibly want to see if you're in the same place next year.

3. All the moths fly in late summer or autumn. They are smaller than the other big silk moths and fly more energetically. They have a very short life as moths (they don't eat) and spend most of it looking for mates, so the easiest way to catch a group is to catch one individual and wait for others to come calling on the first one. Many fly during the daytime. Collecting them (in boxes) is a relatively safe and easy way to control local populations. Some people think the wings are pretty, and a few species or color types are considered rare, but the main reward of collecting buck moths is that people in your neighborhood will be less likely to meet the caterpillars next year.

Hemileuca annulata Ferguson, 1971

Little information is available. Older sources list annulata as a sub-species of eglanterina. Here's a representative sample of what a web search for this species turns up:

Hemileuca artemis Packard, 1893

Moths have black bodies, gray wings with wide creamy-white bands. Even the Moth Photographers Group doesn't have a photo or useful map for this species. This link for H. nevadensis suggests that artemis may be regarded as just a variant form of nevadensis:

Hemileuca burnsi J.H. Watson, 1910

"Burns' Buck Moth." Habitat: California, Arizona, Nevada. Food plants: horsebrush, Fremont Indigo, and Desert Almond. Moths are off-white with brown markings. Caterpillars hatch in February and March; moths fly between August and November. Detailed life history of captive specimens here:

This person reared the caterpillars and doesn't even discuss whether they sting like other members of the genus?

Hemileuca chinatiensis (Tinkham, 1943)

"Chinati Sheep Moth." Habitat: west Texas, southern New Mexico. Food plants: sumac, mimosa, mahonia, acacia and others with, according to, "a marked preference for flower buds over foliage." Moths are dark drab with white markings on wings and yellowish abdomens.

Hemileuca conwayae Peigler, 1985

Some entomology sites have created pages for this species but not filled them in with information on where it's found or how it can be recognized.

Hemileuca dyari (Draudt, 1930)

Another species that's under-documented on the Internet.

Hemileuca eglanterina (Boisduval, 1852)

"Sheep Moth," "Elegant Sheep Moth," "Western Sheep Moth." Habitat: California. Food plants: roses, buckthorns, coffeeberry, ceanothus. Moths are orange and black, some with a contrast between pinkish orange fore wings and yellowish orange hind wings. Caterpillars are described as black with yellow or orange bristles; Steve Stone shares a photo of one with clearly marked dark and light stripes on the skin. Galleries of adult moths' color patterns here:

Hemileuca electra Wright, 1884

Habitat: California, Arizona, Nevada. Food plants: California Buckwheat. Moths have dark gray to black and white fore wings, vivid orange and black hind wings, orange abdominal segments. Caterpillars may have distinct stripes. Moths fly in September.

An interesting string of characters popped up when I searched for information about this moth:

Do they think an interest in moths is psychologically abnormal? This time-lapse video, with repeated sequences (from different angles) of one moth expanding her wings, mating, and laying eggs, might indicate an abnormal interest in the details of an insect's life...

Here's a photo of a caterpillar found in California...

These California specimens may be smaller, as well as more conspicuously patterned, than other stingingworms. Also interesting is the news that, although parasitized caterpillars mature and have time to sting people, parasites do attack Hemileuca. What kind of parasites are they, and where can we get some?

Hemileuca griffini Tuskes, 1978

"Griffin's Sheep Moth." Habitat: Arizona-Utah border. Food plants: "Black Brush." Moths are relatively small for silk moths, only about a two-inch wingspread; brownish or blackish gray and white wings, brown or orange body. shows a caterpillar with well defined black and white lengthwise stripes and greenish bristles.

Hemileuca grotei Grote & Robinson, 1868

"Grote's Buck Moth." Habitat: Texas, Arizona, New Mexico, Colorado. Moths are dark gray and white (patterned very much like maia) with an interesting cryptic stripe pattern on the abdomen. Caterpillars are drab and mottled; this BugGuide photo looks remarkably like maia:

Google also reports some detailed descriptions of Hemileuca grotei and other buck moths in The Wild Silk Moths of North America. A variety called Hemileuca grotei diana has apparently been classified as a separate species (Hemileuca diana) by some authors.

Hemileuca hera (Harris, 1841)

Hera Buckmoth
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"Sagebrush Sheep Moth." Habitat: Western North America from Saskatchewan and New Mexico west. Food plants: primarily sagebrush, can eat lupine and wild buckwheat. Moths are black and white. Caterpillars are predominantly black and have noticeable stripes down the sides.

In Canada, some suspect that these moths may live almost two years, spending one winter in egg form and the next winter in pupal form:

D.L. Strenge verified that individuals could survive two Washington State winters in this way. Strenge also watched, counted, and determined that the average female lays 125 eggs. Other Hemileuca egg clusters look similar to hera's, so 125 is likely to be average for them too.

Hemileuca hualapai (Neumoegen, 1882)

"Hualapai Buck Moth." Habitat: Arizona, New Mexico, Mexico. Food plants include grass. Moths have off-white wings and reddish or orange bodies. Caterpillars may have both lengthwise stripes and crosswise rings, giving some individuals a sort of plaid coloring...

Or not:

Hemileuca juno Packard, 1872

"Juno Buck Moth" or "Mesquite Buck Moth." Habitat: along the U.S.-Mexican border. Food plant: mesquite. Moths are dark gray or black and white, and fly in September or up into December. Moths emerge from their pupal shells in the morning, mate if possible that afternoon, and lay eggs in the evening. Caterpillars could be confused with H. maia, or may have distinct stripes and red bristles. Some pupae may survive, without hatching into moths, through two or three winters.

Hemileuca lares (Druce, 1897)

Pages have been created for this species, but not filled in with information.

Hemileuca lex (Druce, 1897)

Pages have been created, but not filled in with information.

Hemileuca lucina H. Edwards, 1887

"New England Buck Moth." Habitat: New England states, occasionally found further west. Food plant: meadowsweet when the caterpillars first hatch, leaves of trees and bushes later on; like maia, the mature caterpillars are apt to infest orchards and berry patches just when the fruit ripens. Moths have dark gray and white wings, dark gray bodies with red or orange spots. Caterpillars photographed here look like some I've seen in Virginia that may have been H. maia:

They also seem to be as diverse as maia. They may be parasitized by tachinid flies:

Those who want to read a scientific study about the caterpillars' defensive reactions will apparently have to pay...

Hemileuca magnifica (Rotger, 1948)

Magnificent indeed. Habitat: Utah, Arizona, Colorado. Moths are big and showy with dramatic black and white wings, yellowish heads and patches of orange on mostly black bodies. Some early researchers classified this as a subspecies of hera.

Hemileuca maia (Drury, 1773)

"Buck Moth." Habitat: Eastern North America from Texas and Kansas east. Food plants: primarily oak, but late-stage caterpillars nibble on many other plants and particularly favor cherry, blueberry, raspberry, and blackberry, which they visit just when the fruit is ripe. Moths are dark gray and off-white, can look black and white, with red patches on the body. Caterpillars are mottled; predominant colors and patterns vary.

This is, deservingly, the most loathed moth in North America. Bug Guide shows a picture of a well camouflaged caterpillar and the rash it raised on a human hand here: has a photo that seems to explain the name "Buck Moth" for this whole group, although the usual explanation is that the moths fly during deer hunting season (in some places).

This birdwatcher had the patience to snap close-up photos of a pair of moths mating:

In Ohio, this blogger reported a caterpillar still crawling around, looking for trouble, in July:

Some people seem not to know how badly humankind does want these caterpillars to get squished. The stiff bristles protect them from being crushed in the ordinary course of events. This web site recommends using a long, solid stick to transfer a stingingworm onto a rock, a log, or pavement. A less disgusting means of population control is to, er-hum, collect the adult moths; they follow scent trails to find each other so, if you pin one to a display board, other moths are likely to visit. But Hemileuca maia is outrageously over-protected and under-predated. We should not neglect our ecological duty to control populations of this obnoxious species.

Hemileuca mania (Druce, 1897)

When I typed this name into Google, the system initially confused mania with maia. However, mania is a separate species, found in Veracruz in Mexico. That's about all the English-language Internet has to say about it.

Hemileuca marillia Dyar, 1911

A formal scientific bulletin described this species as "known only from a single specimen found in La Paz, Lower California."

Hemileuca mexicana (Druce, 1887)

Found in Mexico, but not much more seems to be known about it:

Hemileuca neumoegeni (H. Edwards, 1881)

"Neumoegen's Buck Moth." Habitat: Southwestern U.S. from California to Colorado. Food plants: squawbush, Desert Almond. Moths have white wings with blackish markings, white upper bodies, russet on abdomen. This photo shows that young caterpillars look less bristly than older caterpillars, which seems to be true for several species, and also that color variation is present even before the caterpillars start wandering about:

Hemileuca nevadensis Stretch, 1872

"Nevada Buck Moth." Habitat: Western North America from Michigan west. Food plants: trees in the willow and poplar families, alder, cottonwood. Moths have black and white fore wings, black and white or yellow hind wings, striped bodies. has a gallery of Hemileuca photos showing that H. nevadensis caterpillars may or may not have a distinct stripe along the side:

Their colors can vary as widely as maia's, and Bugguide refers to maia and nevadensis as forming a "complex" of species "that can get pretty confusing" in the Central States:

Here's an informative, though ultimately alarming, blog post showing several stages in the lives of moths and caterpillars. The moths look a little closer to true black and white than maia, although that could be individual variation, and these individual caterpillars are vividly striped.

The alarming part is that this Wisconsin blogger deliberately introduced stingingworms to an area that had previously been free from them. Although this web site tries to avoid calling for violence, we have to consider the deliberate release of any stingingworm, anywhere, as a violent act.

Hemileuca numa (Druce, 1887)

This official-looking web page says numa is found only in Mexico:

Hemileuca nuttalli (Strecker, 1875)

Habitat: Western North America, Colorado to British Columbia westward. Food plants: bitterbrush, snowberry, currants. Moths fly between July and September. Moths have white and/or yellow and black wings, black and yellow bodies. Caterpillars may share this black-white-and-yellow color scheme.

Hemileuca oliviae Cockerell, 1898

"Range Caterpillar Moth." Habitat: New Mexico, Colorado, western tip of Oklahoma, south into Mexico. Food plant: grass and shrubs. Moths have off-white wings, brown bodies. Caterpillars are considered serious pests for which chemical spraying has been funded.

Natural parasites offer a better prospect for population control:

Hemileuca peigleri Lemaire, 1981

"Texas Buck Moth." Habitat: Texas. Food plant: oaks. Moths are dark gray and white, with proportionately long bodies; bodies are mostly blackish with whitish, yellowish, or orangish patches. Resemblance to maia is strong. Caterpillars can hatch as early as February and pupate in May or June; moths emerge in November and even December.

Hemileuca peninsularis Lemaire, 1993

A search for this species opened the page with all these cool free photos. Here's peninsularis in the way they look best...collected...

Hemileuca peninsularis
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Peninsularis apparently means "of the peninsula of Baja California," but even this Mexican web site has little information to add beyond that:

Hemileuca rubridorsa R. Felder & Rogenhofer, 1874

Found in Mexico, and rare enough that somebody seems to be trying to sell a preserved specimen on E-Bay.

Hemileuca slosseri Peigler & Stone, 1989

"Slosser's Buck Moth." Habitat: Texas. Food plant: "shinnery oak," a weed that has sometimes been sprayed or burned because it also harbors boll weevils. Moths are gray and white with yellowish patches on the body. They fly after the first cold nights of autumn, typically in November.

This writer seems to think that destruction of shinnery oak should be timed in order to protect its resident stingingworms. One meets some peculiar people in cyberspace...

Hemileuca sororia (H. Edwards, 1881)

Back in 1898, T.D.A. Cockerell published a one-page "book" identifying this as a new species...

This old government pamphlet contains a lot of general information about Hemileuca, but I failed to find anything specifically about Hemileuca sororia.

Hemileuca stonei Lemaire, 1993

Habitat: Arizona. Moths are drab with white or yellowish patterns on the wings, white or yellowish heads, and reddish patches on the body.

Hemileuca tricolor (Packard, 1872)

"Tricolor Buck Moth." Habitat: Arizona and New Mexico. Food plants: mesquite and paloverde. Moths have gray and white fore wings with yellow-orange spots, and white or brown hind wings.

Hemileuca tricolor
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