The larva's appearance is generally very different from the adult form (e.g.caterpillars and
butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different.
Larvae are frequently adapted to different environments than adults. For example, some larvae such as
tadpoles live almost exclusively in aquatic environments, but can live outside water as adult
frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population.
Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like
barnacles, adults are immobile but their larvae are mobile, and use their mobile larval form to distribute themselves.
Some larvae are dependent on adults to feed them. In many eusocial
Hymenoptera species, the larvae are fed by female workers. In Ropalidia marginata (a paper wasp) the males are also capable of feeding larvae but they are much less efficient, spending more time and getting less food to the larvae.
The larvae of some organisms (for example, some
newts) can become
pubescent and do not develop further into the adult form. This is a type of
It is a misunderstanding that the larval form always
reflects the group's evolutionary history. This could be the case, but often the larval stage has evolved secondarily, as in insects. In these cases the larval form may differ more than the adult form from the group's common origin.
Protopod larvae – larva have many different forms and often unlike a normal insect form. They hatch from eggs which contain very little
yolk. E.g. first
instar larvae of parasitic hymenoptera.
Polypod larvae – also known as eruciform larvae, these larvae have abdominal prolegs, in addition to usual thoracic legs. They are poorly sclerotized and relatively inactive. They live in close contact with their food. Best example is
caterpillars of lepidopterans.
Oligopod larvae – have well developed head capsule and mouthparts are similar to the adult, but without compound eyes. They have six legs. No abdominal prolegs. Two types can be seen:
Campodeiform – well sclerotized, dorso-ventrally flattened body. Usually long legged predators with
prognathous mouthparts. (lacewing, trichopterans, mayflies and some coleopterans).
Scarabeiform – poorly sclerotized, flat thorax and abdomen. Usually short legged and inactive burrowing forms. (
Scarabaeoidea and other coleopterans).
^Moore, R.C. (1959). Arthropoda I – Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha.
Treatise on Invertebrate Paleontology. Vol. Part O. Boulder, Colorado/Lawrence, Kansas: Geological Society of America/University of Kansas Press. pp. O121, O122, O125.