Tent Caterpillar Identification Guide
Identify these communal caterpillars by their silky tree tents and the distinctive stripe or spot pattern down their backs.
Read the full Tent Caterpillar encyclopedia entry →
Key Visual Features
Tent caterpillars are social moth larvae best known for the large silk tents they build in tree branches.
- Fully grown caterpillars reach about 2 inches (5 cm) long, with a hairy body covered in fine, soft setae rather than stiff spines.
- The body is typically dark with a pattern of blue spots along the sides and a row of markings down the back—many species show a solid white or cream stripe running the length of the back, while others show a row of pale, keyhole-shaped spots instead of a solid line.
- The head is dark and rounded, and the legs near the front are true, jointed legs while soft prolegs appear further back along the body, typical of caterpillars.
- Adult moths are stout-bodied, tan to reddish-brown, with a wingspan of roughly 1.5 inches (4 cm) and two pale diagonal bands across each forewing.
- Egg masses are shiny, dark, and wrapped around small twigs in a solid band, resembling a collar of hardened foam.
Where and When You'd See It
Tent caterpillars are found on deciduous trees such as cherry, apple, and other fruit or hardwood trees, where they construct silk tents in the forks of branches. Caterpillars emerge in early spring as leaves begin to open, feeding communally and returning to the tent to rest, especially during cool mornings and evenings or wet weather. The tent grows larger as the colony develops through spring, and caterpillars disperse to pupate by early summer, spinning individual cocoons in bark crevices or nearby structures. Adult moths emerge in mid to late summer and are most often seen at night near lights.
Similar-Looking Bugs
- Fall webworms build similar silk nests but do so in late summer and enclose the leaves themselves within the web, whereas tent caterpillars build a tent at branch forks and leave the surrounding foliage exposed.
- Gypsy moth caterpillars are hairy and similarly colored but lack the organized silk tent behavior, instead scattering individually across foliage.
- Eastern and forest tent caterpillars look nearly identical to each other, distinguished mainly by whether the back marking is a solid stripe or a row of separate spots.
- Woolly bear caterpillars are uniformly fuzzy without the blue side spots or back stripe and do not build communal tents.
Quick ID Checklist
- Hairy caterpillar with blue spots along the sides
- Solid pale stripe or row of spots running down the back
- Found in groups near a silk tent at a branch fork
- Active in early spring, feeding communally on new leaves
- Adult moth is tan-brown with two pale diagonal wing bands
Frequently asked questions
How can I tell a tent caterpillar from a fall webworm?
Tent caterpillars build their silk tent at a branch fork early in spring and feed outside it, while fall webworms enclose the leaves they eat within a web later in summer.
What is the key back marking to look for?
Look for either a solid pale stripe or a row of pale, spot-like markings running down the length of the caterpillar's back, depending on the species.
Do all tent caterpillars build tents in the same spot?
They typically build in the fork of tree branches where several limbs meet, expanding the silk structure as the colony grows.
What does the adult tent caterpillar moth look like?
It is a stout, tan to reddish-brown moth with a roughly 1.5-inch wingspan and two pale diagonal bands crossing each forewing.