Larva
A distinct juvenile form before metamorphosis in many animals.
A larva is a distinct juvenile form that many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase of their life cycle. A larva's appearance is generally very different from the adult form, including different unique structures and organs that do not occur in the adult form, and their diet may also be considerably different.
- field
- Developmental biology, entomology
- known_for
- Juvenile stage preceding metamorphosis in many animals
- characteristics
- Distinct from adult form; often adapted to different environments; may have unique structures and organs
Lore & Background
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 polychaetes, barnacles, and sea squirts, adults are immobile but their larvae are mobile, using their mobile larval form to distribute themselves. These larvae used for dispersal are either planktotrophic (feeding) or lecithotrophic (non-feeding).
Reader's Guide
The larval stage is significant because it represents a critical period of development and dispersal for many animal groups. In insects, only Endopterygotes show complete metamorphosis, including a distinct larval stage. Some larvae are dependent on adults to feed them; in many eusocial Hymenoptera species, larvae are fed by female workers. In Ropalidia marginata, males are also capable of feeding larvae but are much less efficient. The larvae of some organisms, such as some salamanders like the axolotl, can become pubescent and not develop further into the adult form, a type of neoteny. It is a misunderstanding that the larval form always reflects the group's evolutionary history; often the larval stage has evolved secondarily, as in insects.
Did You Know?
- In smaller primitive arachnids, the larval stage differs by having three instead of four pairs of legs.
- Some larvae, like tadpoles, live almost exclusively in aquatic environments but can live outside water as adult frogs.
- In Ropalidia marginata, males can feed larvae but are much less efficient than females.
- The larvae of some organisms, such as the axolotl, can become pubescent and not develop further into the adult form, a type of neoteny.
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