Pine Processionary Moth Identification Guide
Identify this Mediterranean moth by its plain gray-white wings and the famous nose-to-tail marching lines formed by its caterpillars.
Read the full Pine Processionary Moth encyclopedia entry →
Key Visual Features
The Pine Processionary Moth (Thaumetopoea pityocampa) is a modestly patterned moth with a wingspan of about 1.4 to 1.8 inches (3.5 to 4.5 cm). On its own, the adult is relatively plain and easy to overlook:
- Forewings in pale gray to grayish-brown, marked with faint, indistinct darker gray wavy lines or bands
- Hindwings that are whitish to pale gray, generally unmarked or very faintly marked
- A stocky, moderately furry gray-brown body
- Short, feathery antennae, more strongly comb-like in males than in females
- A generally understated, camouflage-toned appearance typical of many night-flying moths in this family
The moth's egg masses, laid in cylindrical clusters wrapped around pine needles and coated in gray-brown scales, are also a useful clue when searching directly on pine branches. However, this species is most famously identified not by the adult moth but by its larvae: densely hairy grayish caterpillars that travel in long, continuous nose-to-tail processions across the ground or up tree trunks, sometimes stretching many feet in a single unbroken line.
Where and When You'll See It
This species is native to the Mediterranean region, including southern Europe and North Africa, and inhabits pine and cedar forests, plantations, and parks. Adults fly at night in late summer, typically July through September, and are attracted to lights, though they are seen far less often than the conspicuous caterpillars. The caterpillars build large, silken communal nests (visible as white, tent-like structures) high in pine branches during winter, then emerge in spring, typically February through April depending on climate, to march in their characteristic head-to-tail processions in search of soil to pupate in.
Similar-Looking Moths
- Oak Processionary Moth: A close relative with a similar plain grayish adult appearance, distinguished mainly by host tree (oak rather than pine) and slightly different caterpillar coloring and nest placement.
- Other Thaumetopoea species: Share the plain gray wing pattern; regional range and host tree are the most reliable ways to separate them, since the adults look very similar to one another.
- Common gray tussock or lappet moths: Can appear superficially similar at rest, but lack the characteristic silken communal nests and processionary caterpillar behavior.
Quick ID Checklist
- Plain grayish-brown adult moth, wingspan roughly 1.4–1.8 inches, easily overlooked
- Faint wavy lines on forewings, pale unmarked hindwings
- Feathery antennae, more pronounced in males
- Distinctive silken tent-like nests high in pine branches over winter
- Caterpillars form long, continuous head-to-tail marching lines in spring
Frequently asked questions
Why is this moth easier to identify by its caterpillars than the adult?
The adult moth has a plain, understated gray-brown pattern that resembles many other night-flying moths, whereas the caterpillars' unmistakable nose-to-tail marching processions and large silken tree nests make this life stage far easier to recognize in the field.
What time of year do the processions happen?
The caterpillars typically leave their winter nests and march in long processions during late winter to spring, roughly February through April depending on local climate.
How can I find the winter nests of this species?
Look for large, white, silken, tent-like structures built high up among the needles of pine or cedar branches, which the caterpillars construct and shelter in during the colder months.
Where is the Pine Processionary Moth found?
It is native to the Mediterranean region, including southern Europe and North Africa, and is closely tied to pine and cedar forests and plantations.