Monarch Caterpillar
Scientific Name: Danaus plexippus (larval stage)
Order & Family: Order: Lepidoptera, Family: Nymphalidae (Brush-footed butterflies)
Size: Newly hatched caterpillars are about 2-3 mm (0.08-0.12 inches) long. Fully grown caterpillars (fifth instar), like the larger ones in the image, can reach up to 4.5-5 cm (1.8-2 inches) in length.
Natural Habitat
Monarch caterpillars are found wherever their host plants, milkweed, grow. This includes meadows, fields, roadsides, gardens, and along forest edges throughout North and South America, especially in regions with temperate climates during their breeding season.
Diet & Feeding
Monarch caterpillars exclusively feed on the leaves of milkweed plants (Asclepias species). The specific milkweed type is Common Milkweed (Asclepias syriaca) based on the appearance of the pods in the image.
Behavior Patterns
Monarch caterpillars spend most of their time eating and growing. They go through five instars (stages between molts) before pupating. During each instar, they shed their skin. Once large enough, they will form a chrysalis, typically hanging upside down from a stem or leaf, where they will metamorphose into an adult butterfly. The adult butterflies are known for their spectacular long-distance migrations.
Risks & Benefits
Risks: No direct risks to humans. Benefits: Monarchs are important pollinators. Their iconic migration is a natural wonder. The caterpillars' consumption of milkweed helps disperse milkweed seeds. They are a keystone species for many ecosystems and their population health is an indicator of environmental health. Their existence is vital for biodiversity.
Identified on: 8/10/2025