Larva Of Eudocima Tyrannus (Saitama, Japan) 20190928131605 Ed1
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A larva (; : larvae ) is a distinct juvenile form many
animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...
s undergo before
metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...
into their next life stage. Animals with indirect
development Development or developing may refer to: Arts *Development (music), the process by which thematic material is reshaped * Photographic development *Filmmaking, development phase, including finance and budgeting * Development hell, when a proje ...
such as
insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
s, some
arachnid Arachnids are arthropods in the Class (biology), class Arachnida () of the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, opiliones, harvestmen, Solifugae, camel spiders, Amblypygi, wh ...
s,
amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...
s, or
cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...
ns typically have a larval phase of their
life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from conception to reproduction *Life-cycle hypothesis, in economics *Erikson's stages of psy ...
. A larva's appearance is generally very different from the adult form (''e.g.''
caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...
s and
butterflies Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...
) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. In the case of smaller primitive arachnids, the larval stage differs by having three instead of four pairs of legs. Larvae are frequently adapted to different environments than adults. For example, some larvae such as
tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...
s live almost exclusively in aquatic environments but can live outside water as adult
frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
s. 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
polychaete Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...
s and
barnacle Barnacles are arthropods of the subclass (taxonomy), subclass Cirripedia in the subphylum Crustacean, Crustacea. They are related to crabs and lobsters, with similar Nauplius (larva), nauplius larvae. Barnacles are exclusively marine invertebra ...
s, adults are immobile but their larvae are mobile, and use their mobile larval form to distribute themselves. These larvae used for dispersal are either planktotrophic (feeding) or lecithotrophic (non-feeding). Some larvae are dependent on adults to feed them. In many eusocial
Hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typi ...
species, the larvae are fed by female workers. In ''
Ropalidia marginata ''Ropalidia marginata'' is an Old World species of paper wasp. It is primitively eusocial, not showing the same bias in brood care seen in other social insects with greater asymmetry in relatedness. The species employs a variety of colony foundi ...
'' (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
newt A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aqua ...
s) can become
pubescent The adjective pubescent may describe: * people or animals undergoing puberty * plants that are hairy, covered in trichomes * insects that are covered in setae In biology, setae (; seta ; ) are any of a number of different bristle- or hair-lik ...
and do not develop further into the adult form. This is a type of
neoteny Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the Physiology, physiological, or Somatic (biology), somatic, development of an organism, typically an animal. Neoteny i ...
. 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 origins.


Selected types of larvae


Insect larvae

Within
Insects Insects (from Latin ') are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed ...
, only
Endopterygote Holometabola (from Ancient Greek "complete" + "change"), also known as Endopterygota (from "inner" + "wing" + Neo-Latin "-having"), is a supra- ordinal clade of insects within the infraclass Neoptera that go through distinctive larval, pupal ...
s show complete metamorphosis, including a distinct larval stage. Several classifications have been suggested by many
entomologists Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos''), meaning "study") is the branch of zoology that focuses on insects. Those who study entomology are known as entomologists. In ...
, and the following classification is based on
Antonio Berlese Antonio Berlese (26 June 1863, in Padua, Austrian Empire – 24 October 1927, in Florence) was an Italian entomologist. Career Berlese worked on pest insects notably of fruit trees. He published over 300 articles and a book ''Gli insetti loro o ...
classification in 1913. There are four main types of endopterygote larvae types: # Apodous larvae – no legs at all and are poorly sclerotized. Based on
sclerotization Sclerotization is a biochemical process that produces the rigid shell of sclerotin that comprises an insect's chitinous exoskeleton. It is prominent in the thicker, armored parts of insects and arachnid Arachnids are arthropods in the Class (b ...
. All Apocrita are apodous. Three
apodous Many vertebrates are limbless, limb-reduced, or apodous, with a body plan consisting of a head and vertebral column, but no adjoining limbs such as legs or fins. Jawless fish are limbless but may have preceded the evolution of vertebrate limbs, w ...
forms are recognized. #* Eucephalous – with well-sclerotized head capsule. Found in
Nematocera The Nematocera (the name meaning "thread-horns") are a suborder of elongated fly, flies with thin, segmented antenna (biology), antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies except for species from suborder ...
,
Buprestidae Buprestidae is a family (biology), family of beetles known as jewel beetles or metallic wood-boring beetles because of their glossy Iridescence, iridescent colors. Larvae of this family are known as flatheaded borers. The family is among the lar ...
and
Cerambycidae The longhorn beetles (Cerambycidae), also known as long-horned or longicorns (whose larvae are often referred to as roundheaded borers), are a large family of beetles, with over 35,000 species described. Most species are characterized by anten ...
families. #* Hemicephalus – with a reduced head capsule, retractable into the thorax. Found in
Tipulidae Tipulidae is a family of large Crane fly, crane flies in the order Diptera. There are more than 30 genera and 4,200 described species in Tipulidae, common and widespread throughout the world. A crane fly can be identified as a member of Tipuli ...
and
Brachycera The Brachycera are a suborder of the order Diptera. It is a major suborder consisting of around 120 families. Their most distinguishing characteristic is reduced antenna segmentation. Description A summary of the main physical characteristic ...
families. #* Acephalus – without head capsule. Found in
Cyclorrhapha Cyclorrhapha is an Taxon#Ranks, unranked taxon within the infraorder (biology), infraorder Muscomorpha. They are called "Cyclorrhapha" ('circular-seamed flies') with reference to the circular aperture through which the adult escapes the puparium. ...
# Protopod larvae – larvae have many different forms and often are unlike a normal insect form. They hatch from eggs which contain very little
yolk Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...
. E.g. first
instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...
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. The best example is the
caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...
s of lepidopterans. # Oligopod larvae – have well-developed head capsules and mouthparts that are similar to 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 Prognathism is a positional relationship of the mandible or maxilla to the skeletal base where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull. In the case of ''mandibular'' prognathism (nev ...
mouthparts. (lacewing, trichopterans, mayflies and some coleopterans). #* Scarabeiform – poorly sclerotized, flat thorax and abdomen. Usually short-legged and inactive burrowing forms. (
Scarabaeoidea Scarabaeoidea is a superfamily of beetles, the only subgroup of the infraorder Scarabaeiformia. Around 35,000 species are placed in this superfamily and some 200 new species are described each year. Some of its constituent families are undergo ...
and other coleopterans).


See also

*
Crustacean larvae Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow. The ...
*
Ichthyoplankton Ichthyoplankton (from Greek: ἰχθύς, , "fish"; and πλαγκτός, , "drifter") are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the ep ...
*
Maggots A maggot is the larva of a fly (order Diptera); it is applied in particular to the larvae of Brachycera flies, such as houseflies, cheese flies, hoverflies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and cran ...
*
Spawn (biology) Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is known as spawning. The ...
* Non-larval animal juvenile (immature) stages and other
life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from conception to reproduction *Life-cycle hypothesis, in economics *Erikson's stages of psy ...
stages: ** In
Porifera Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a Basal (phylogenetics) , basal clade and a sister taxon of the Eumetazoa , diploblasts. They are sessility (motility) , sessile ...
: olynthus,
gemmule Gemmules are internal buds found in sponges and are involved in asexual reproduction. It is an asexually reproduced mass of cells, that is capable of developing into a new organism i.e., an adult sponge. Role in asexual reproduction Asexual re ...
** In
Cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...
: ephyra, scyphistoma,
strobila Strobilation or transverse fission is a form of asexual reproduction consisting of the spontaneous transverse segmentation of the body. It is observed in certain cnidarians and helminths. This mode of reproduction is characterized by high offsprin ...
,
gonangium {{Short pages monitor