The death's head moth, and why it has a skull on its back

The death's head moth is drawn far more often than it is seen, and most of the drawings are wrong in the same way: too flat, too symmetrical, and with the skull far too tidy. The animal itself is stranger than the ornament. It is a big, fast, blunt-nosed hawkmoth that squeaks when you pick it up and breaks into beehives to drink honey. Here is what is actually true about it.

What the animal actually is

There are three species in the genus Acherontia, all of them hawkmoths, family Sphingidae. The European one is Acherontia atropos, which breeds across Africa and around the Mediterranean and pushes north in summer as a migrant. It reaches Britain and Ireland most years in small numbers, usually from late summer into autumn, and only occasionally breeds there.

It is large. Wingspan is roughly 100mm to 130mm, which makes it one of the biggest moths you can find in northern Europe, and the body is heavy and conical like the rest of the hawkmoths. The forewings are mottled brown and charcoal, the hindwings are a dull yellow banded with black, and the abdomen is banded too. The caterpillar is bigger still, a fat green or yellow thing with diagonal side stripes and a curved horn at the back end, and it feeds mainly on plants in the nightshade family, including potato.

If you want to see one in the wild, the realistic route is the caterpillar rather than the adult: look along potato haulm in late summer in the south of its range. The adults come to light, which is how most records are made, but they are not common and nobody should promise you one.

The skull is a pattern, not a design

The mark sits on the thorax, the section behind the head, and it is made of pale scales on a dark ground. Depending on the individual it reads as a long skull with two dark eye sockets and a band of teeth, or as nothing much at all. The variation between individuals is wide, and a worn specimen often loses the pattern entirely because the scales rub off.

What it is for is not settled. Hawkmoth thoraxes carry markings in many species and the usual explanations are disruptive patterning, which breaks up the outline of a resting insect, or a startle effect on a predator that has just turned the moth over. Nothing requires the pattern to look like a human skull, and the resemblance is almost certainly in our heads rather than in the moth's evolutionary history. Faces are the one shape people see everywhere, including in wall sockets and tree bark.

That is worth holding onto, because the moth is sold hard as an omen. It is a brown insect with pale scales in a pattern we happen to find legible.

It squeaks, and it raids beehives

Acherontia is one of the few moths that makes an audible noise. When handled or disturbed it forces air in and out through the pharynx, past a small flap, producing a sharp chirp you can hear from across a room. It is not stridulation of the cricket sort and it is not made with the wings.

The adults also break into honeybee colonies and drink honey from the comb. The proboscis is short, thick and stiff compared with other hawkmoths, which suits piercing wax rather than reaching into flowers. Research on how they survive the visit points to chemical camouflage, with the moth's cuticle carrying compounds that keep the bees from treating it as an intruder, and to a cuticle thick enough to resist the stings it does get. Treat that as the current explanation rather than a closed case.

Where the name came from

Linnaeus described the European species in 1758, as Sphinx atropos. Atropos is one of the three Fates of Greek myth, the one who cuts the thread, and the genus name added later comes from Acheron, a river of the Greek underworld. The two Asian species carry the names styx and lachesis, which keeps the theme going.

So the funereal reading is not something the twentieth century invented and hung on an innocent insect. The naturalists who formally described it got there first, in Latin, in the middle of the eighteenth century.

How it got into pictures

Keats has it in the Ode on Melancholy, published in 1820: "Nor let the beetle, nor the death-moth be / Your mournful Psyche". By then the moth had a reputation in rural Europe as a bad sign, and people recorded beliefs that its appearance in a house meant a death coming. That is a belief people held, not a fact about the insect, and it is the kind of claim that attaches to anything large, dark and nocturnal.

The nineteenth century also put it in cabinets. Victorian entomology turned insects into furniture: glazed cases, pinned rows, printed labels. A moth with a skull on its back was always going to be a prize specimen, and that is how most people first saw one, dead and under glass.

The modern image comes from one book and one poster. Thomas Harris used the moth in The Silence of the Lambs in 1988, and the 1991 film's poster placed one over the lead actor's mouth. The skull printed on that moth is not a moth marking at all: it is Philippe Halsman's 1951 photograph In Voluptas Mors, made with Salvador Dali, in which nude models are arranged into the shape of a skull. Almost every death's head moth drawn since has been copying a poster that was itself a composite.

Why it works as a motif

Practically, the moth is a good shape for a small object. It is bilaterally symmetrical, which makes it easy to cast and easy to balance on a chain. The wings resolve into two clean triangles, so the silhouette survives being shrunk, and that matters when a cast pendant like the moth choker is only a few centimetres across.

The colours help too. A brown and charcoal insect with a dull yellow hindwing sits easily next to brass and black, where a tropical butterfly would fight everything in the room. Where a piece combines the moth with a skull outright, as this pendant does, it is really putting two memento mori motifs in one object, one of them several hundred years older than the other.

At larger sizes the detail can come back. A cut iron piece like The Moth, Cut From Iron has room for antennae and wing veining that a 20mm casting has to throw away, and the difference between a good moth and a vague one is usually whether the maker kept the thorax reading as a thorax.

Common mistakes in moth imagery

The skull is drawn centred on the wings rather than on the thorax, which turns the insect into a logo. On the real animal the mark is small and sits forward, between the wing bases.

The antennae are drawn feathered. Hawkmoth antennae are relatively plain and taper to a point, and the big feathered antennae belong to other families, notably the silk moths. If you are choosing between two cast moths and one has elaborate plumes, it is a saturniid wearing the wrong name.

Finally, the wings are drawn spread flat. A living hawkmoth at rest holds its wings swept back along the body in a narrow delta, which is a better and less obvious shape than the flat specimen pose that every pinned insect in every case has taught us to expect.

Questions people actually ask

Is the skull on a death's head moth real?

The pattern is real. It is made of pale scales on the moth's thorax and varies a lot between individuals. The resemblance to a human skull is coincidental: nothing suggests the pattern evolved to look like one.

Do death's head moths really squeak?

Yes. When disturbed they force air through the pharynx and produce an audible chirp. It is one of very few moths that makes a noise you can hear without equipment.

What does the death's head moth eat?

The caterpillars feed on plants in the nightshade family, including potato. The adults drink nectar and also break into honeybee nests to take honey, using a short, stiff proboscis.