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The caddisflies, or
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
Trichoptera, are a group of
insect Insects (from Latin ') are pancrustacean 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 ...
s with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders
Integripalpia The Integripalpia are a suborder of Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into th ...
and
Annulipalpia The Annulipalpia, also known as the "fixed-retreat makers", are a suborder of Trichoptera, the caddisflies.Glenn B. Wiggins, ''Larvae of the North American Caddisfly Genera (Trichoptera)'', 2nd. ed. (Toronto: University Press, 1996), p. 117 The na ...
on the basis of the adult mouthparts. Integripalpian larvae construct a portable casing to protect themselves as they move around looking for food, while Annulipalpian larvae make themselves a fixed retreat in which they remain, waiting for food to come to them. The affinities of the small third suborder
Spicipalpia The Spicipalpia are a suborder of Trichoptera, the caddisflies. The four families included in this suborder all have the character of pointed maxillary palps in the adults. The larvae of the different families have varying lifestyles, from free-l ...
are unclear, and
molecular analysis Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...
suggests it may not be
monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
. Also called sedge-flies or rail-flies, the adults are small
moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...
-like insects with two pairs of hairy membranous
wings A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expresse ...
. They are closely related to the
Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...
(moths and butterflies) which have scales on their wings; the two orders together form the superorder
Amphiesmenoptera Amphiesmenoptera is an insect superorder, established by S. G. Kiriakoff, but often credited to Willi Hennig in his revision of insect taxonomy for two sister orders: Lepidoptera (butterflies and moths) and Trichoptera (caddisflies). In 2017, a t ...
. The aquatic
larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...
e are found in a wide variety of habitats such as streams, rivers, lakes, ponds, spring seeps and temporary waters (
vernal pool Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe ...
s).Glenn B. Wiggins, ''Larvae of the North American Caddisfly General (Trichoptera)'', 2nd. ed. (Toronto: University Press, 1996), p. 3 The larvae of many species use
silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the coc ...
to make protective cases, which are often strengthened with gravel, sand, twigs, bitten-off pieces of plants, or other debris. The larvae exhibit various feeding strategies, with different species being predators, leaf shredders, algal grazers, or collectors of particles from the water column and
benthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.fly fishing Fly fishing is an angling method that uses a light-weight lure—called an artificial fly—to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. The light weight requires casting techniques significantly diffe ...
, artificial flies are tied to imitate adults, while larvae and pupae are used as bait. Common and widespread genera such as ''
Helicopsyche ''Helicopsyche'' is a genus of Trichoptera, the caddisflies. ''Helicopsyche'' contains more than 230 species and are represented on all major faunal regions with highest diversity in tropical and sub-tropical regions. The genus was first describe ...
'' and ''
Hydropsyche ''Hydropsyche'' is a genus of netspinning caddisflies in the family Hydropsychidae. There are at least 260 described species in ''Hydropsyche''. Taxonomic note: *Type species: Hydropsyche cinerea FJ Pictet (selected by HH Ross, 1944, BullIllinois ...
'' are important in the sport, where caddisflies are known as "sedges". Caddisflies are useful as
bioindicator A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other sma ...
s, as they are sensitive to
water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water ...
and are large enough to be assessed in the field. In art, the French artist
Hubert Duprat Hubert Duprat is a French artist known for his unusual work, an artistic intersection between caddisfly larvae and gold, opal, turquoise and other precious stones. Caddisfly larvae live in fresh water and naturally construct elaborate protective t ...
has created works by providing caddis larvae with small grains of gold and precious stones for them to build into decorative cases.


Etymology

The name of the order "Trichoptera" derives from the
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
: (', "hair"), genitive ''trichos'' + (', "wing"), and refers to the fact that the wings of these insects are bristly. The origin of the word "caddis" is unclear, but it dates back to at least as far as
Izaak Walton Izaak Walton (baptised 21 September 1593 – 15 December 1683) was an English writer. Best known as the author of ''The Compleat Angler'', he also wrote a number of short biographies including one of his friend John Donne. They have been colle ...
's 1653 book ''
The Compleat Angler ''The Compleat Angler'' (the spelling is sometimes modernised to ''The Complete Angler'', though this spelling also occurs in first editions) is a book by Izaak Walton. It was first published in 1653 by Richard Marriot in London. Walton continu ...
'', where "cod-worms or caddis" were mentioned as being used as bait. The term ''cadyss'' was being used in the fifteenth century for silk or cotton cloth, and "cadice-men" were itinerant vendors of such materials, but a connection between these words and the insects has not been established.


Evolution and phylogeny


Fossil history

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
caddisflies have been found in rocks dating back to the
Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
. The largest numbers of fossilised remains are those of larval cases, which are made of durable materials that preserve well. Body fossils of caddisflies are extremely rare, the oldest being from the Early and Middle Triassic, some 230 million years ago, and wings are another source of fossils. The evolution of the group to one with fully aquatic larvae seems to have taken place sometime during the Triassic. The finding of fossils resembling caddisfly larval cases in marine deposits in Brazil may push back the origins of the order to the
Early Permian 01 or '01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), 01'' (Richard Müller album), 2001 * 01 (Son of Dave album), ''01'' (Son of Dave album), 2000 * 01 (Urban ...
period.


Evolution

Nearly all adult caddisflies are terrestrial, but their larvae and pupae are aquatic. They share this characteristic with several distantly-related groups, namely the
dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...
,
mayflies Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the orde ...
,
stoneflies Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mo ...
,
alderflies Alderflies are megalopteran insects of the family Sialidae. They are closely related to the dobsonflies and fishflies as well as to the prehistoric Euchauliodidae. All living alderflies – about 66 species all together – are part of the subfa ...
and
lacewings The insect order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order consists of some 6,000 species. Neuroptera can be grouped together with the Megaloptera and Raphidioptera in the ...
. The ancestors of all these groups were terrestrial, with open tracheal systems, convergently evolving different types of gills for their aquatic larvae as they took to the water to avoid predation. About 14,500 species of caddisfly in 45 families have been recognised worldwide, but many more species remain to be described. Most can be divided into the suborders
Integripalpia The Integripalpia are a suborder of Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into th ...
and
Annulipalpia The Annulipalpia, also known as the "fixed-retreat makers", are a suborder of Trichoptera, the caddisflies.Glenn B. Wiggins, ''Larvae of the North American Caddisfly Genera (Trichoptera)'', 2nd. ed. (Toronto: University Press, 1996), p. 117 The na ...
on the basis of the adult mouthparts. The characteristics of adults depend on the
palp Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and ...
s,
wing venation Insect wings are adult outgrowths of the insect exoskeleton that enable insects to flight, fly. They are found on the second and third Thorax (insect anatomy), thoracic segments (the mesothorax and metathorax), and the two pairs are often referre ...
and
genitalia A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...
of both sexes. The latter two characters have undergone such extensive differentiation among the different superfamilies that the differences between the suborders is not clear-cut. The larvae of Annulipalpians are campodeiform (free-living, well sclerotized, long legged predators with dorso-ventrally flattened bodies and protruding mouthparts). The larvae of Integripalpians are polypod (poorly sclerotized detritivores, with abdominal prolegs in addition to thoracic legs, living permanently in tight-fitting cases). The affinities of the third suborder,
Spicipalpia The Spicipalpia are a suborder of Trichoptera, the caddisflies. The four families included in this suborder all have the character of pointed maxillary palps in the adults. The larvae of the different families have varying lifestyles, from free-l ...
, are unclear; the larvae are free-living with no cases, instead creating net-like traps from silk.


Phylogeny

The
cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
of external relationships, based on a 2008 DNA and
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
analysis, shows the order as a
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
,
sister A sister is a woman or a girl who shares one or more parents with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to refer to ...
to the Lepidoptera, and more distantly related to the
Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
(true flies) and
Mecoptera Mecoptera (from the Greek: ''mecos'' = "long", ''ptera'' = "wings") is an order of insects in the superorder Endopterygota with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their lar ...
(scorpionflies). The cladogram of relationships within the order is based on a 2002 molecular phylogeny using ribosomal RNA, a nuclear elongation factor gene, and mitochondrial cytochrome oxidase. The Annulipalpia and Integripalpia are clades, but the relationships within the Spicipalpia are unclear.


Distribution

Caddisflies are found worldwide, with the greater diversity being in warmer regions. They are associated with bodies of freshwater, the larvae being found in lakes, ponds, rivers, streams and other water bodies. The land caddis, ''
Enoicyla pusilla ''Enoicyla pusilla'' also known as the land caddis and the terrestrial caddis is a species of caddisfly in the family Limnephilidae. The genus ''Enoicyla'' is unique among caddisflies because the larvae are terrestrial, living in leaf litter. Di ...
'' (family:
Limnephilidae __NOTOC__ Limnephilidae is a family of caddisflies with about 100 genera. They belong to the main lineage of case-constructing caddisflies, the Integripalpia or tube-case caddisflies. The Limnephilidae is one of the most species-rich Trichoptera f ...
), lives in the damp litter of the woodland floor. In the United Kingdom it is found in and around the county of
Worcestershire Worcestershire ( , ; written abbreviation: Worcs) is a county in the West Midlands of England. The area that is now Worcestershire was absorbed into the unified Kingdom of England in 927, at which time it was constituted as a county (see His ...
in
oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
woods.


Ecology

Caddisfly larvae can be found in all feeding guilds in freshwater habitats. Most early stage larvae and some late stage ones are collector-gatherers, picking up fragments of organic matter from the
benthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.periphyton Periphyton is a complex mixture of algae, cyanobacteria, heterotrophic microbes, and detritus that is attached to submerged surfaces in most aquatic ecosystems. The related term Aufwuchs (German "surface growth" or "overgrowth") refers to the col ...
that grows on underwater objects in sunlight. Others are shredder-herbivores, chewing fragments off living plant material while others are shredder-detritivores, gnawing at rotting wood or chewing dead leaves that have been pre-processed by bacteria and fungi; most of the nutrients of the latter group come from consumption of the bacteria and fungi. The predatory species either actively hunt their prey, typically other insects, tiny crustaceans and worms, or lie in wait for unwary invertebrates to come too close. A few species feed opportunistically on dead animals or fish, and some
Leptoceridae The family Leptoceridae are a family of caddisflies often called "long-horned caddisflies". Leptoceridae is the second largest family of caddisflies with more than 1500 species in around 45 genera. The main identifying feature of most Leptoceri ...
larvae feed on freshwater sponges. One such opportunistic species is ''
Gumaga nigricula ''Gumaga'' is a genus of bushtailed caddisflies in the family Sericostomatidae. There are about six described species in ''Gumaga''. The type species In zoological nomenclature, a type species (''species typica'') is the species name w ...
'' (family:
Sericostomatidae Sericostomatidae is a family of bushtailed caddisflies in the order Trichoptera. There are about 19 genera and at least 90 described species in Sericostomatidae. The type genus In biological taxonomy, the type genus is the genus which ...
) which has been observed scavenging fish carcasses and even bits of deer flesh. This particular family of caddisflies are typically classified as shredders, suggesting caution when classifying macroinvertebrates into strict ecological functional groups, as some may shift their diets opportunistically. Like mayflies, stoneflies and dragonflies, but to a somewhat lesser extent, caddisflies are an indicator of good water quality; they die out of streams with polluted waters. They are an important part of the
food web A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Another name for food web is consumer-resource system. Ecologists can broadly lump all life forms into one ...
, both larvae and adults being eaten by many fish. The newly hatched adult is particularly vulnerable as it struggles to the surface after emerging from the submerged pupa, and as it dries its wings. The fish find these new adults easy pickings, and fishing flies resembling them can be successful for anglers at the right time of year. The adult stage of a caddisfly may only survive for a few weeks; many species do not feed as adults and die soon after breeding, but some species are known to feed on nectar. The winged insects are nocturnal and provide food for night-flying birds, bats, small mammals, amphibians and arthropods. The larval stage lasts much longer, often for one or more years, and has a bigger impact on the environment. They form an important part of the diet of fish such as the
trout Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salmoni ...
. The fish acquire them by two means, either plucking them off vegetation or the stream-bed as the larvae move about, or during the daily behavioural drift; this drift happens during the night for many species of aquatic larvae, or around midday for some cased caddisfly species, and may result from population pressures or be a dispersal device. The larvae may drift in great numbers either close to the bottom, in mid-water or just below the surface. The fish swallow them whole, case and all.


Underwater structures


Cases

Caddisflies are best known for the portable cases created by their larvae. About thirty families of caddisfly, members of the suborder Integripalpia, adopt this stratagem. These larvae eat
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
, largely decaying vegetable material, and the dead leaf fragments on which they feed tend to accumulate in hollows, in slow-moving sections of streams and behind stones and tree roots. The cases provide protection to the larvae as they make their way between these resources. The case is a tubular structure made of
silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the coc ...
, secreted from salivary glands near the mouth of the larva, and is started soon after the egg hatches. Various reinforcements may be incorporated into its structure, the nature of the materials and design depending on the larva's genetic makeup; this means that caddisfly larvae can be recognised by their cases down to family, and even genus level. The materials used include grains of sand, larger fragments of rock, bark, sticks, leaves, seeds and mollusc shells. These are neatly arranged and stuck onto the outer surface of the silken tube. As the larva grows, more material is added at the front, and the larva can turn round in the tube and trim the rear end so that it does not drag along the substrate. Caddisfly cases are open at both ends, the larvae drawing oxygenated water through the posterior end, over their gills, and pumping it out of the wider, anterior end. The larvae move around inside the tubes and this helps maintain the water current; the lower the oxygen content of the water, the more active the larvae need to be. This mechanism enable caddisfly larvae to live in waters too low in oxygen content to support stonefly and mayfly larvae. File:Caddisfly-larva.jpg, Larva with portable case of rock fragments File:Caddisfly_Larva.jpg, Larva emerging from case made of plant material File:Trichoptera larvenbau.jpeg, Larval case of
Limnephilidae __NOTOC__ Limnephilidae is a family of caddisflies with about 100 genera. They belong to the main lineage of case-constructing caddisflies, the Integripalpia or tube-case caddisflies. The Limnephilidae is one of the most species-rich Trichoptera f ...
made of bitten-off plant pieces File:L flavicornis 22088905 cropped.png, Case of ''
Limnephilus flavicornis ''Limnephilus'' is a genus of caddisflies in the family Limnephilidae. There are over 180 species of ''Limnephilus'', described between 1824 and 1999. Several species of ''Limnephilus'' are endangered, including '' Limnephilus perpusillus'', ...
'' made of snail shells


Fixed retreats

In contrast to larvae that have portable cases, members of the Annulipalpia have a completely different feeding strategy. They make fixed retreats in which they remain stationary, waiting for food to come to them. Members of the
Psychomyiidae The Psychomyiidae are a family of tube-making caddisflies. Members of this family are typically very similar to polycentropodids, most of them can be differentiated by the spur formula is 2-4-4, thyridial cell short, absence of the forewing for ...
,
Ecnomidae The Ecnomidae are a family of caddisflies comprising 9 genera with a total of 375 species. Distribution The Ecinomidae have a Gondwanan distribution, except one genus, which also is present in Oriental and Palearctic regions. Morphology The ad ...
and
Xiphocentronidae The Xiphocentronidae are a family of caddisflies. It has previously been treated as a subfamily of Psychomyiidae, and has a broad distribution, including parts of Asia, Central Africa and the Americas The Americas, which are sometimes co ...
families construct simple tubes of sand and other particles held together by silk and anchored to the bottom, and feed on the accumulations of silt formed when suspended material is deposited. The tube can be lengthened when the growing larva needs to feed in new areas. More complex tubes, short and flattened, are built by
Polycentropodidae The Polycentropodidae are a family of trumpet-net and tube-making caddisflies. There are at least 30 genera and 720 described species in Polycentropodidae. The type genus for Polycentropodidae is '' Polycentropus'' J. Curtis, 1835. The larvae ...
larvae in hollows in rocks or other submerged objects, sometimes with strands of silk suspended across the nearby surface. These larvae are carnivorous, resembling spiders in their feeding habits and rushing out of their retreat to attack any unwary small prey crawling across the surface.


Silk domes

Larvae of members of the family Glossosomatidae in the suborder Spicipalpia create dome-shaped enclosures of silk which enables them to graze on the periphyton, the biological film that grows on stones and other objects, while carrying their enclosure around like
turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...
s. In the family
Philopotamidae Philopotamidae is a family of insects in the order Trichoptera, the caddisflies. They are known commonly as the finger-net caddisflies.microflora Microbiota are the range of microorganisms that may be commensal, symbiotic, or pathogenic found in and on all multicellular organisms, including plants. Microbiota include bacteria, archaea, protists, fungi, and viruses, and have been found to ...
that get trapped in the net as water flows through.


Nets

The larvae of other species of caddisfly make nets rather than cases. These are silken webs stretching between aquatic vegetation and over stones. These net-making larvae usually live in running water, different species occupying different habitats with varying water speeds. There is a constant drift of invertebrates washed downstream by the current, and these animals, and bits of debris, accumulate in the nets which serve both as food traps and as retreats.


Development and morphology

Caddisfly larvae are aquatic, with six pairs of tracheal gills on the underside of the abdomen. The eggs are laid above water on emergent twigs or vegetation or on the water surface although females of some species enter water to choose sites. Although most species lay eggs, a few in the genus ''Triplectides'' are ovoviviparous. Some species lay eggs on land and although most are associated with freshwater, a few like ''Symphitoneuria'' are found in coastal saline water. ''Philanisus plebeius'' females lay their eggs into the coelomic cavity of intertidal starfish. The larvae are long and roughly cylindrical, very similar to those of lepidoptera but lacking prolegs. In case-bearing species, the heads are heavily
sclerotised Sclerotin is a component of the cuticle of various Arthropoda, most familiarly insects. It is formed by cross-linking members of particular classes of protein molecules, a biochemical process called sclerotization, a form of tanning in which qui ...
while the abdomen is soft; the antennae are short and the mouthparts adapted for biting. Each of the usually ten abdominal segments bears a pair of legs with a single tarsal joint. In case-bearing species, the first segment bears three papillae, one above and two at the sides, which anchor the larva centrally in the tube. The posterior segment bears a pair of hooks for grappling. There are five to seven larval
instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...
s, followed by an aquatic
pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...
which has functional mandibles (to cut through the case), gills, and swimming legs. The pupal cocoon is spun from silk, but like the larval case, often has other materials attached. When pupating, species that build portable cases attach them to some underwater object, seal the front and back apertures against predators while still allowing water to flow through, and pupate within it. Once fully developed, most pupal caddisflies cut through their cases with a special pair of mandibles, swim up to the water surface,
moult In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
using the
exuviae In biology, exuviae are the remains of an exoskeleton and related structures that are left after ecdysozoans (including insects, crustaceans and arachnids) have moulted. The exuviae of an animal can be important to biologists as they can often b ...
as a floating platform, and emerge as fully formed adults. They can often fly immediately after breaking from their pupal cuticle. Emergence is mainly univoltine (once per year) with all the adults of a species emerging at the same time. Development is within a year in warm places, but takes over a year in high latitudes and at high elevation in mountain lakes and streams. The adult caddisfly is a medium-sized insect with membranous, hairy wings, which are held in a tent-wise fashion when the insect is at rest. The antennae are fairly long and threadlike, the mouthparts are reduced in size and the legs have five tarsi (lower leg joints). Adults are nocturnal and are attracted to light. Some species are strong fliers and can disperse to new localities, but many fly only weakly. Adults are usually short-lived, most being non-feeders and equipped only to breed. Once mated, the female caddisfly lays eggs in a gelatinous mass, attaching them above or below the water surface depending on species. The
egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
s hatch in a few weeks. File:GT Caddis Fly Egg Mass on leaf.jpg, Egg mass on leaf away from water File:CaddisPupaBMNH.jpg, Pupa with oar-like swimming legs File: Caddis pupae.JPG, Pupae File:Parachiona.picicornis.emerging.jpg, ''
Parachiona picicornis ''Parachiona'' is a genus of insects belonging to the family Limnephilidae __NOTOC__ Limnephilidae is a family of caddisflies with about 100 genera. They belong to the main lineage of case-constructing caddisflies, the Integripalpia or tube-cas ...
'' adult emerging from aquatic pupa File:Daternomina male tagged.png, Adult


Relationship with humans


In angling

Adult caddisflies are called sedges by anglers. Individual species emerge ''en masse'' at different times, and are used one after the other, often for only a few days each year, as models for artificial
fishing flies An artificial fly or fly lure is a type of fishing lure, usually used in the sport of fly fishing (although they may also be used in other forms of angling). In general, artificial flies are an imitation of aquatic insects that are natural food ...
for
fly fishing Fly fishing is an angling method that uses a light-weight lure—called an artificial fly—to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. The light weight requires casting techniques significantly diffe ...
in trout streams. A mass emergence is known as a hatch. Each type has its own angling name, so for example ''
Mystacides ''Mystacides'' is a genus of long-horned caddisflies in the family Leptoceridae The family Leptoceridae are a family of caddisflies often called "long-horned caddisflies". Leptoceridae is the second largest family of caddisflies with more th ...
'' is the dancer; ''
Sericostoma ''Sericostoma'' is a genus of bushtailed caddisflies in the family Sericostomatidae Sericostomatidae is a family of bushtailed caddisflies in the order Trichoptera. There are about 19 genera and at least 90 described species in Sericostomatidae ...
'' the caperer; ''
Leptocerus ''Leptocerus'' is a genus of long-horned caddisflies in the family Leptoceridae The family Leptoceridae are a family of caddisflies often called "long-horned caddisflies". Leptoceridae is the second largest family of caddisflies with more th ...
'' the silverhorn; ''
Phryganea ''Phryganea'' is a genus of giant casemakers in the family Phryganeidae. There are about 13 described species in the genus. The type species In zoological nomenclature, a type species (''species typica'') is the species name with which ...
'' the murragh or great red sedge; '' Brachycentrus subnubilis'' the grannom; ''
Lepidostoma ''Lepidostoma'' is a genus of bizarre caddisflies in the family Lepidostomatidae Lepidostomatidae is a family in the order Trichoptera. It is widely dispersed around the world. Larvae shapes vary. Larvae are normally found near bodies of water. ...
'' the silver sedge; ''
Oecetis ''Oecetis'' is a genus of long-horned caddisfly, long-horned caddisflies in the family Leptoceridae. There are at least 410 described species in ''Oecetis''. See also * List of Oecetis species References Further reading * * * External ...
'' the longhorn sedge; ''
Cheumatopsyche ''Cheumatopsyche'' is a genus of netspinning caddisflies in the family Hydropsychidae The Hydropsychidae are a family-level taxon consisting of net-spinning caddisflies. Hydropsychids are common among much of the world's streams, and a few sp ...
'' the little sister sedge; ''
Helicopsyche ''Helicopsyche'' is a genus of Trichoptera, the caddisflies. ''Helicopsyche'' contains more than 230 species and are represented on all major faunal regions with highest diversity in tropical and sub-tropical regions. The genus was first describe ...
'' the speckled Peter, an important fishing fly in North America; and ''
Hydropsyche ''Hydropsyche'' is a genus of netspinning caddisflies in the family Hydropsychidae. There are at least 260 described species in ''Hydropsyche''. Taxonomic note: *Type species: Hydropsyche cinerea FJ Pictet (selected by HH Ross, 1944, BullIllinois ...
'' the specked sedge, perhaps the most important caddisfly genus for anglers with over 50 species of net-makers.


As bioindicators

Caddisflies are useful as
bioindicator A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other sma ...
s (of good water quality), since they are sensitive to
water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water ...
, and are large enough to be assessed conveniently in the field. Some species indicate undisturbed habitat, and some indicate degraded habitat. Although caddisflies may be found in waterbodies of varying qualities, species-rich caddisfly assemblages are generally thought to indicate clean water bodies, such as lakes, ponds, and
marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...
es. Together with
stoneflies Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mo ...
and mayflies, caddisflies feature importantly in bioassessment surveys of streams and other water bodies.


In art

While caddisflies in the wild construct their cases out of twigs, sand, aquatic plants, and rocks, the French artist
Hubert Duprat Hubert Duprat is a French artist known for his unusual work, an artistic intersection between caddisfly larvae and gold, opal, turquoise and other precious stones. Caddisfly larvae live in fresh water and naturally construct elaborate protective t ...
makes art by providing wild caddisflies with precious stones and other materials. He collected caddisfly larvae from the wild and put them in climate-controlled tanks. He removes the larvae from their original cases and adds precious and semi-precious items such as grains of gold into the tank. The larvae then build new cases out of precious items, creating a unique form of artwork. The resulting works are sold across the world.


As food

In Japan the caddisfly larvae is called ''Zazamushi'' and eaten as a delicacy."Zazamushi Silk" - Successful Discovery and Analysis of Novel Silk Protein Genes from caddisfly larvae
/ref>


Taxonomy

There are roughly 14,500 species in some 45 families worldwide. * Suborder
Annulipalpia The Annulipalpia, also known as the "fixed-retreat makers", are a suborder of Trichoptera, the caddisflies.Glenn B. Wiggins, ''Larvae of the North American Caddisfly Genera (Trichoptera)'', 2nd. ed. (Toronto: University Press, 1996), p. 117 The na ...
** Superfamily
Hydropsychoidea The Hydropsychoidea are a superfamily of caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided i ...
*** Family
Dipseudopsidae Dipseudopsidae is a family of caddisflies in the order Trichoptera. There are about 6 genera and at least 110 described species in Dipseudopsidae. The type genus for Dipseudopsidae is '' Dipseudopsis'' F. Walker, 1852. The oldest fossils are of ...
*** Family
Ecnomidae The Ecnomidae are a family of caddisflies comprising 9 genera with a total of 375 species. Distribution The Ecinomidae have a Gondwanan distribution, except one genus, which also is present in Oriental and Palearctic regions. Morphology The ad ...
*** Family † Electralbertidae *** Family
Hydropsychidae The Hydropsychidae are a family-level taxon consisting of net-spinning caddisflies. Hydropsychids are common among much of the world's streams, and a few species occupy the shorelines of freshwater lakes. Larvae of the hydropsychids construct ...
*** Family
Polycentropodidae The Polycentropodidae are a family of trumpet-net and tube-making caddisflies. There are at least 30 genera and 720 described species in Polycentropodidae. The type genus for Polycentropodidae is '' Polycentropus'' J. Curtis, 1835. The larvae ...
*** Family
Psychomyiidae The Psychomyiidae are a family of tube-making caddisflies. Members of this family are typically very similar to polycentropodids, most of them can be differentiated by the spur formula is 2-4-4, thyridial cell short, absence of the forewing for ...
*** Family
Xiphocentronidae The Xiphocentronidae are a family of caddisflies. It has previously been treated as a subfamily of Psychomyiidae, and has a broad distribution, including parts of Asia, Central Africa and the Americas The Americas, which are sometimes co ...
** Superfamily
Philopotamoidea The Philopotamoidea are a superfamily level taxon of the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of ...
*** Family
Philopotamidae Philopotamidae is a family of insects in the order Trichoptera, the caddisflies. They are known commonly as the finger-net caddisflies.Stenopsychidae The Stenopsychidae are a family of medium to large caddisflies, some of which are noted for their black and gold wing patterns. The family contains three genera and some 70 species, which can be found in the Ethiopian, Palaearctic, Oriental, and ...
* Suborder
Integripalpia The Integripalpia are a suborder of Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into th ...
** Superfamily
Leptoceroidea Leptoceroidea is a superfamily of caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the ...
*** Family
Atriplectididae ''Atriplectididae'' is a family of caddisflies belonging to the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, mos ...
*** Family
Calamoceratidae Calamoceratidae is a family of caddisflies in the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which ca ...
*** Family
Molannidae Molannidae is a family of Hood casemakers in the order Trichoptera. There are at least 3 genera and 40 described species in Molannidae. The type genus In biological taxonomy, the type genus is the genus which defines a biological family and th ...
*** Family
Leptoceridae The family Leptoceridae are a family of caddisflies often called "long-horned caddisflies". Leptoceridae is the second largest family of caddisflies with more than 1500 species in around 45 genera. The main identifying feature of most Leptoceri ...
*** Family Limnocentropodidae *** Family
Odontoceridae Odontoceridae is a family of mortarjoint casemakers in the order Trichoptera. There are about 12 genera and at least 100 described species in Odontoceridae. The type genus In biological taxonomy, the type genus is the genus which defin ...
*** Family
Philorheithridae Philorheithridae is a family of caddisflies in the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which c ...
** Superfamily
Limnephiloidea Limnephiloidea is a superfamily of Trichoptera, the caddisflies. Please see the taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, e ...
*** Family
Apataniidae Apataniidae is a family of early smoky wing sedges in the order Trichoptera. There are about 18 genera and at least 180 described species in Apataniidae. The type genus In biological taxonomy, the type genus is the genus which defines ...
*** Family
Brachycentridae Brachycentridae is a family of humpless casemaker caddisflies in the order Trichoptera. It is found in North America, Europe, and Asia. Georg Ulmer first described it in Germany in 1903 as a subfamily of Sericostomatidae.Ulmer, p. 18. The type g ...
*** Family
Goeridae Goeridae is a family of caddisflies in the order Trichoptera. There are about 12 genera and at least 160 described species in Goeridae. The type genus In biological taxonomy, the type genus is the genus which defines a biological family ...
*** Family
Limnephilidae __NOTOC__ Limnephilidae is a family of caddisflies with about 100 genera. They belong to the main lineage of case-constructing caddisflies, the Integripalpia or tube-case caddisflies. The Limnephilidae is one of the most species-rich Trichoptera f ...
*** Family
Lepidostomatidae Lepidostomatidae is a family in the order Trichoptera. It is widely dispersed around the world. Larvae shapes vary. Larvae are normally found near bodies of water. It was first discovered by Georg Ulmer in 1903. Distribution It is normally found ...
*** Family
Oeconesidae Oeconesidae is a family of caddisflies in the order Trichoptera. There are about 6 genera and 19 described species in Oeconesidae, found mainly in New Zealand. A single species, ''Tascuna ignota'', is found in Tasmania ) , nickname ...
*** Family
Pisuliidae Pisuliidae is a small family of insects in the order Trichoptera found in tropical Africa and Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: Répub ...
*** Family Rossianidae *** Family † Taymyrelectronidae *** Family
Uenoidae Uenoidae is a family of stonecase caddisflies in the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which ...
** Superfamily † Necrotaulioidea *** Family †
Necrotauliidae Necrotauliidae is an extinct family Mesozoic Amphiesmenoptera. While previously considered a paraphyletic grouping of "basal Trichoptera, basal Lepidoptera, and advanced stem-Amphiesmenoptera", they have recently been considered early diverging c ...
** Superfamily
Phyrganeoidea Phryganeoidea is a giant caddisfly superfamily that may be paraphyletic with Limnephiloidea Limnephiloidea is a superfamily of Trichoptera, the caddisflies. Please see the taxonomy Taxonomy is the practice and science of categorization o ...
*** Family †
Baissoferidae Baisserferidae is an extinct family in the order Trichoptera (caddis flies). Its fossil dates range from 161 to 112 million years old. It was lacustrine and terrestrial and was found in the Jurassic range of Russia and the Cretaceous range of Mon ...
*** Family †
Dysoneuridae Dysoneuridae is an extinct family of insect in the order Trichoptera, the caddisflies. The family was first described by I.D. Sukacheva (also spelled Sukatsheva) in 1968, and lived from the Middle Jurassic to mid-Cretaceous. In Wichard et al. (20 ...
*** Family †
Kalophryganeidae Kalophryganeidae is an extinct family in the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be ...
*** Family Phyrganeidae *** Family Phyrganopsychidae *** Family
Plectrotarsidae Plectrotarsidae is a small Australasian family of insects in the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, m ...
** Superfamily
Sericostomatoidea Sericostomatoidea is a superfamily in the order Trichoptera, the caddisflies. Families include:Anomalopsychidae ''Anomalopsychidae'' is a family of caddisflies belonging to the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, mo ...
*** Family
Antipodoeciidae ''Antipodoecia'' is a monotypic genus of caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided int ...
*** Family Barbarochthonidae *** Family
Beraeidae Beraeidae is a family of caddisflies belonging to the order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which ...
*** Family Calocidae *** Family
Chathamiidae Chathamiidae is a family of case making caddisflies more commonly known as the marine caddisflies. Chathamiids are unique among insects in their invasion of the tide pool environment. Larvae construct their cases of coralline algae. The four des ...
*** Family
Conoesucidae Conoesucidae is a family of caddisflies in the order Trichoptera. There are about 12 genera and more than 40 described species in Conoesucidae. Genera These 12 genera belong to the family Conoesucidae: * '' Beraeoptera'' Mosely, 1953 * '' Coeno ...
*** Family Helicophidae *** Family
Helicopsychidae Helicopsychidae (snail-case caddisflies) are a family of Trichoptera. The name refers to the helix shaped larval cases and they should not be confused with Limnephilidae which sometimes inhabit the snail shells. Their shells range from and are c ...
*** Family Hydrosalpingidae *** Family
Kokiriidae Kokiriidae is a family of insect in the order Trichoptera. It was discovered in 1964 and is found in Australia, Chile, New Caledonia, and New Zealand. It consists of fifteen species and six genera. History It was originally erected in 1964 as ...
*** Family Petrothrincidae *** Family
Sericostomatidae Sericostomatidae is a family of bushtailed caddisflies in the order Trichoptera. There are about 19 genera and at least 90 described species in Sericostomatidae. The type genus In biological taxonomy, the type genus is the genus which ...
** Superfamily
Tasimioidea The Tasimiidae is a family of Trichoptera, erected in 1968 (Riek). The family is found in Australia and Chile. The genera ''Tricovespula'' was originally placed in the Lepidostomatidae, but it was placed in the Tasmiidae by Flint (1969). Tasimiid ...
*** Family
Tasimiidae The Tasimiidae is a family of Trichoptera, erected in 1968 (Riek). The family is found in Australia and Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in th ...
** Superfamily † Vitimotaulioidea *** Family † Vitimotauliidae *** Family † Cladochoristidae *** Family † Microptysmatidae *** Family † Prosepididontidae *** Family † Protomeropidae *** Family † Uraloptysmatidae * Suborder
Spicipalpia The Spicipalpia are a suborder of Trichoptera, the caddisflies. The four families included in this suborder all have the character of pointed maxillary palps in the adults. The larvae of the different families have varying lifestyles, from free-l ...
** Superfamily
Hydroptiloidea The Hydroptilidae are a large family of caddisflies (Trichoptera) with a worldwide distribution. They are commonly known as microcaddisflies or purse-case caddisflies, in reference to two characteristic traits of this family: Hydroptilidae are ...
*** Family
Glossosomatidae The Glossosomatidae are a family of the class Insecta and order Trichoptera.The family contains 23 genera in three subfamilies. In the US alone, there are 76 spp. in 6 different genera.Merritt, RW, Cummins, KW, Berg MB. (2008). An Introduction to ...
*** Family
Hydroptilidae The Hydroptilidae are a large family of caddisflies (Trichoptera) with a worldwide distribution. They are commonly known as microcaddisflies or purse-case caddisflies, in reference to two characteristic traits of this family: Hydroptilidae are ...
*** Family Ptilocolepidae ** Superfamily
Rhyacophiloidea :''"Rhyacophiloidea" may also be the name of the entire "Spicipalpia", when these are treated as a superfamily inside the Annulipalpia.'' The Rhyacophiloidea are a superfamily in the insect order Trichoptera The caddisflies, or order Trichopte ...
*** Family
Hydrobiosidae The Hydrobiosidae are a family of caddisflies in the insect order Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most o ...
*** Family
Rhyacophilidae The Rhyacophilidae are a family in the insect order of Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can ...


References


Further reading

A useful reference to the larvae of the British Trichoptera is "Caddis Larvae" Norman E. Hickin (1967) Hutchinson & Co. Ltd. London.
Caddisfly
Troutster.com


External links



- Videos of some very interesting caddisfly species in Arizona.
Caddisflies and Fly Fishing
- Photos, limited species life history descriptions.

— diagnostic photographs and information


Tree of Life Trichoptera page

Trichoptera world checklist



Artwork with caddis fly larvae and precious metals!
"An unusual artistic collaboration between the French artist Hubert Duprat and a group of caddis fly larvae."
Caddisfly larvae
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