The hornworm is the larval (caterpillar) stage of the sphinx moth (Manduca sexta). Hornworms have a body mass equivalent to approximately 20 crickets and are an excellent source of calories and nutrients for your reptiles, amphibians, or arachnids. Hornworms are also a great source of additional moisture for an insectivore whose diet consists mainly of crickets, mealworms, giant mealworms and superworms.