Where Do Caterpillars Go to Pupate? Understanding Chrysalis and Cocoon Sites

Caterpillar Pupation: Chrysalis vs. Cocoon

If you're hosting caterpillars in your garden but can't find their pupae, you're not alone. The location and structure of the pupal stage depend entirely on whether the caterpillar will become a butterfly or a moth.

Butterflies: The Chrysalis

Butterfly caterpillars do not spin a silk cocoon. Instead, they attach themselves to a secure surface—often a leaf, twig, stem, or nearby structure—using a silk pad and a hook-like cremaster at their rear. They then shed their final larval skin to reveal a hardened, protective chrysalis (also called a pupa). The chrysalis is often camouflaged, blending with the host plant or surrounding bark.

Moths: The Cocoon

Many moth caterpillars spin a protective cocoon from silk, often incorporating leaves, twigs, or their own hairs. These cocoons may be:

• Attached to the host plant (under leaves, on branches)
• Hidden in leaf litter on the ground
• Buried in the soil near the host plant
• Suspended from a silk thread

Species-Specific Behavior

Pupation sites vary widely by species. For example:

• Monarch butterflies often pupate on the host milkweed or nearby vegetation.
• Swallowtails may attach to stems, fences, or buildings.
• Luna moths spin cocoons in leaf litter on the ground.
• Tomato hornworms burrow into soil to pupate.

Tips for Finding Pupae

• Search the host plant thoroughly—check undersides of leaves, stems, and nearby structures.
• Look in leaf litter and topsoil around the base of the plant.
• Observe caterpillars in late instar; they often wander before pupating.
• Provide vertical sticks or branches in rearing containers to give them attachment options.

Remember: the absence of visible cocoons doesn't mean caterpillars aren't pupating—they may be well-hidden or using a chrysalis instead.