Acharia stimulea, commonly known as the saddleback caterpillar, is a strikingly colorful species found in deciduous forests across the eastern United States. It features a vibrant green saddle-shaped marking on its back, surrounded by brown, and is known for its distinct venomous spines that provide defense against predators.

Acharia stimulea, commonly known as the saddleback caterpillar, is native to North America. Its geographical distribution predominantly includes the eastern United States, extending from New York to Florida and westward to Missouri and Texas. The species is also found in parts of Central America.

The saddleback caterpillar thrives in temperate to subtropical climates, often found in deciduous forests, woodlands, and areas with abundant vegetation. It prefers environments where its host plants, such as oak, cherry, and citrus trees, are plentiful.

Acharia stimulea occupies the ecological niche of a herbivore and is primarily a leaf feeder. The caterpillar is known for its distinctive appearance and venomous spines, which serve as a defense mechanism against predators. Its presence in various plant species can influence the local food web dynamics, particularly involving predators and parasitoids that have adapted to its defenses.