Hornworms (Goliath or often called tomato worms ) are larvae of the Manduca sexta , a type of sphinx moth. These worms are used as food for reptiles, especially lizards and other insectivores. They are very nutritious, rich in protein and water, making them very hydrating for reptiles. Hornworms are also relatively low in fat, making them a healthy option when given in moderation. They are particularly popular for their size (quite large) and tender texture, ideal for medium and large reptiles.