Aquatic insects or water insects live some portion 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 ...

in the water. They feed in the same ways as other

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 ''diving'' insects, such as

predatory Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

diving beetle The Dytiscidae, from the Ancient Greek word δυτικός (''dystikos''), meaning "able to dive", are the predaceous diving beetles, a Family (biology), family of water beetles. They occur in virtually any freshwater habitat around the world, bu ...

s, can hunt for food underwater where land-living insects cannot

compete Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, individ ...

Breathing

One problem that aquatic insects must overcome is how to get

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

while they are under water. Almost all animals require a source of oxygen to live. Insects draw air into their bodies through spiracles, holes found along the sides of the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

. These spiracles are connected to tracheal tubes where oxygen can be absorbed. All aquatic insects have become adapted to their environment with the specialization of these structures ;Aquatic adaptations # Simple diffusion over a relatively thin

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, Exoskeleton, shell, germ or Peel (fruit), rind. Etymology The term is derived from ''integumentum'', which is Latin for "a coverin ...

# Temporary use of an air bubble # Extraction of oxygen from water using a

plastron The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the turtle's vital organs and in some cases even the head. It is constructed of modified bony elements such ...

blood gill A blood gill is a gill-like structure restricted to organs with spacious lumen and poorly developed/absent trachea, found in larvae of aquatic insects. Specific research questions the functionality of this gill to respiration Respiration may refer ...

# Storage of oxygen in

hemoglobin Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin ...

and

hemocyanin Hemocyanins (also spelled haemocyanins and abbreviated Hc) are proteins that transport oxygen throughout the bodies of some invertebrate animals. These metalloproteins contain two copper atoms that reversibly bind a single oxygen molecule (O2 ...

molecules in

hemolymph Hemolymph, or haemolymph, is a fluid, similar to the blood in invertebrates, that circulates in the inside of the arthropod's body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph c ...

# Taking oxygen from surface via breathing tubes ( siphons) The nymphs of the

hemimetabolous Hemimetabolism or hemimetaboly, also called partial metamorphosis and paurometabolism,McGavin, George C. ''Essential Entomology: An Order-by-Order Introduction''. Oxford: Oxford University Press, 2001. pp. 20. is the mode of development of certain ...

orders mayflies, dragonflies and stoneflies, and the larvae of the

holometabolous Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the clade Holometabola. Immatur ...

orders

megaloptera Megaloptera is an order of insects. It contains the alderflies, dobsonflies and fishflies, and there are about 300 known species. The order's name comes from Ancient Greek, from ''mega-'' (μέγα-) "large" + ''pteryx'' (πτέρυξ) "wi ...

ns and caddisflies, possess tracheal gills, which are outgrowths of the body wall containing a dense network of tracheae covered by a thin cuticle through which oxygen in the water can diffuse. Some insects have densely packed hairs (

setae In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae ...

) around the spiracles that allow air to remain near, while keeping water away from, the body. The trachea open through spiracles into this air film, allowing access to oxygen. In many such cases, when the insect dives into the water, it carries a layer of air over parts of its surface, and breathes using this trapped air bubble until it is depleted, then returns to the surface to repeat the process. Other types of insects have a

or physical gill that can be various combinations of hairs, scales, and undulations projecting from the cuticle, which hold a thin layer of air along the outer surface of the body. In these insects, the volume of the film is small enough, and their respiration slow enough, that

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...

from the surrounding water is enough to replenish the oxygen in the pocket of air as fast as it is used. The large proportion of

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

in the air dissolves in water slowly and maintains the gas volume, supporting oxygen diffusion. Insects of this type only rarely need to replenish their supply of air. Other aquatic insects can remain under water for long periods due to high concentrations of hemoglobin in their hemolymph circulating freely within their body. Hemoglobin bonds strongly to oxygen molecules. A few insects such as

water scorpion Nepidae is a family of exclusively aquatic Heteropteran insects in the order Hemiptera. They are commonly called water scorpions for their superficial resemblance to scorpions, due to their raptorial forelegs and the presence of a long slender p ...

s and

mosquito larvae Mosquitoes, the Culicidae, are a family of small flies consisting of 3,600 species. The word ''mosquito'' (formed by '' mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mosquitoes have a slender segmented body, ...

have breathing tubes ("siphons") with the opening surrounded by

hydrofuge In chemistry and materials science, ultrahydrophobic (or superhydrophobic) surfaces are highly hydrophobic, i.e., extremely difficult to wet. The contact angles of a water droplet on an ultrahydrophobic material exceed 150°. This is also refer ...

hairs, allowing them to breathe without having to leave the water.

Orders with aquatic or semiaquatic species

*Collembola -

springtail Springtails (class Collembola) form the largest of the three lineages of modern Hexapoda, hexapods that are no longer considered insects. Although the three lineages are sometimes grouped together in a class called Entognatha because they have in ...

s (which are not technically insects, but are closely related) *Ephemeroptera -

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 order ...

Odonata Odonata is an order of predatory flying insects that includes the dragonflies and damselflies (as well as the '' Epiophlebia'' damsel-dragonflies). The two major groups are distinguished with dragonflies (Anisoptera) usually being bulkier with ...

dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of dragonflies are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...

and

damselflies Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies (which constitute the other odonatan suborder, Epiprocta) but are usually smaller and have slimmer bodies. Most species fold the win ...

Plecoptera Plecoptera is an order (biology), 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 b ...

- stoneflies *

Megaloptera Megaloptera is an order of insects. It contains the alderflies, dobsonflies and fishflies, and there are about 300 known species. The order's name comes from Ancient Greek, from ''mega-'' (μέγα-) "large" + ''pteryx'' (πτέρυξ) "wi ...

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 ...

fishflies Fishflies are members of the subfamily Chauliodinae, belonging to the megalopteran family Corydalidae. They are most easily distinguished from their closest relatives, dobsonflies, by the jaws (mandibles) and antennae. In contrast to the large j ...

, and

dobsonflies Dobsonflies are a subfamily of insects, Corydalinae, part of the Megalopteran family Corydalidae. The larvae (commonly called hellgrammites) are aquatic, living in streams, and the adults are often found along streams as well. The nine genera ...

Neuroptera The insect order (biology), order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order consists of some 6,000 species. Neuroptera is grouped together with the Megaloptera (alderflies, f ...

- lacewings *Coleoptera -

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

s *

Hemiptera Hemiptera (; ) is an order of insects, commonly called true bugs, comprising more than 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from ...

- true bugs (

water striders The Gerridae are a family of insects in the order Hemiptera, commonly known as water striders, water skeeters, water scooters, water bugs, pond skaters, water skippers, water gliders, water skimmers or puddle flies. They are true bugs of the ...

, giant water bugs) *

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 ...

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

s (e.g. ''

Polyrhachis sokolova '' Polyrhachis sokolova'' is a species of ant from Australia and New Guinea that recently was discovered to be capable of surviving tidal inundations. Researchers at the James Cook University gained attention in 2006 after finding and reportin ...

'') and

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder ...

s (e.g. '' Microgaster godzilla'') *Diptera -

flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...

Mecoptera Mecoptera (from the Greek language, Greek: ''mecos'' = "long", ''ptera'' = "wings") is an Order (biology), order of insects in the superorder Holometabola with about six hundred species in nine Family (biology), families worldwide. Mecopterans a ...

- scorpionflies *

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

s *Trichoptera -

caddisflies The caddisflies (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 suborders Integripalpia and Annulipalpia on the basis ...

EPT insects, an

acronym An acronym is a type of abbreviation consisting of a phrase whose only pronounced elements are the initial letters or initial sounds of words inside that phrase. Acronyms are often spelled with the initial Letter (alphabet), letter of each wor ...

for Ephemeroptera, Plecoptera and Trichoptera (mayflies, stoneflies and caddisflies), are sensitive to pollutants and are used as an indicator of water quality in streams, rivers and lakes.

Marine aquatic insects

Aquatic insects live mostly in

freshwater habitat Freshwater ecosystems are a subset of Earth's aquatic ecosystems that include the biological communities inhabiting freshwater waterbodies such as lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ec ...

s, and there are very few marine insect species. The only true examples of

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

insects are the sea skaters, which belongs to the order Hemiptera, and there are a few types of insects that live in the

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

, including larvae of

from the family Chathamiidae, the hemipteran '' Aepophilus bonnairei'', and a few other taxa.

References

* Farb, P. (1962). The Water Dwellers IFENSECTS pg. 142. * Meyer, J.R. (2006),
Respiration in Aquatic Insects
. (Accessed 25 April 2008) * Wigglesworth, Vincent B. Sir (1964). The life of insects. Weidenfeld & Nicolson, London

External links

- "Some larvae, nymphs and adult insects that live in freshwater." ''A UK-based web site with microscopic photos of various insects and other microorganisms as well as biological information.'' {{Authority control