What is the difference between a grub, a caterpillar and a nymph?
AThese are names for the immature forms of insects whose life history involves a metamorphosis. In some, such as house fly maggots, beetle grubs, crane-fly leatherjackets and moth and butterfly caterpillars, the transformation happens all in one go, during an intermediate pupal stage. In the case of dragonflies, mayflies and grasshoppers, however, metamorphosis is gradual, each youngster passing through several developmental stages (instars) separated by a moult. These forms are known collectively as nymphs. If in doubt, it’s usually safe to use the broadest term, larva – a bit of a catchall that can also be used for the young forms of other animals that undergo some form of developmental metamorphosis, including amphibian tadpoles, lamprey ammocoetes, crab zoea, sea urchin plutei, the planulae of jellyfish, corals and anemones, and literally dozens of crustacean forms.
A caterpillar feasts on milk parsley before pupating, to emerge as a spectacular swallowtail butterfly.