Raising Swallowtail Butterfly Larvae to Adult: A Complete Record to Enjoy with Children

Finding Larvae! Tips for Collection and Timing

To raise Swallowtail butterfly larvae, you must first find them. Since Swallowtail caterpillars feed on citrus family plants, carefully observe mandarin orange, lemon, yuzu, and Japanese pepper trees in your garden. May through September is the ideal collection season, and June through August in particular is the easiest time to find larvae since they lay eggs multiple times during this period.

The larvae are often found on the surface or underside of leaves and near stems. Young larvae (1st to 3rd instar) have a black and white mottled pattern that mimics bird droppings. At this stage they are very small and easy to miss, so carefully inspect each leaf one by one. From the 4th instar onward, they turn green and eyespots (ocelli) appear. Once they reach this size, they become easier to spot with the naked eye.

When collecting, be sure to take not just the larvae but also the leaves they were eating. Larvae are easily stressed by sudden environmental changes, so it's reassuring to secure as many leaves as possible from the original plant. Place them in a plastic container or small box and bring them home.

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Preparing the Raising Container and Setting Up the Environment

For home raising, an insect cage or large plastic container from a home center or 100-yen shop is sufficient. Ideally, the lid should have ventilation holes, but you can also improvise by securing a cloth or gauze with rubber bands.

The two key points are "space" and "cleanliness." When larvae reach their final instar (5th), they grow to about 5-6 cm in length and actively move around the container searching for a place to pupate. Choose a container that can provide at least 30 cm tall by 20 cm wide of space.

Lining the bottom with newspaper or kitchen paper makes cleaning droppings much easier. Remove droppings daily and maintain cleanliness along with replacing leaves—this is the foundation of disease prevention. Especially in summer, leaves deteriorate easily, and leaving rotted leaves can cause soft rot disease in the larvae, so be careful.

The ideal temperature for the raising environment is 25-30°C. Avoid direct sunlight and place the container in a well-ventilated indoor location. High humidity can lead to mold on leaves and droppings, so ensure adequate ventilation.