Aquatic
Guides
Benacus
Benacus is a genus of giant water bugs in the family Belostomatidae, subfamily Lethocerinae. The genus was established by Stål in 1861 and contains species of large aquatic predatory insects. Spermatogenesis has been studied cytologically in Benacus griseus, revealing 28 spermatogonial chromosomes and distinct cytoplasmic inclusions including chondriosomes and Golgi bodies during sperm development.
Bezzia nobilis
Bezzia nobilis is a biting midge in the family Ceratopogonidae, widely considered one of the most common species in the genus Bezzia. It has a notably broad geographic distribution spanning Eurasia, North America, Central America, and South America. Adults are distinguished by black and yellow banded legs, while larvae and pupae have characteristic coloration and morphological features. The species is predatory, with larvae feeding on immobile prey including dead insects, bacteria, and protozoa.
Blephariceridae
Net-winged Midges
Blephariceridae, or net-winged midges, are a family of nematoceran flies distinguished by wings with a distinctive network of fissures and folds resembling cracked glass. Adults superficially resemble crane flies but differ in wing shape, head structure, and leg posture. Larvae are specialized inhabitants of torrential streams, possessing six ventral suckers that enable attachment to rocks in flows exceeding 2 m/s. The family contains over 200 species across dozens of genera worldwide, with highest diversity in mountainous regions. Larvae are ecologically significant as diatom grazers in lotic ecosystems.
Blethisa
Blethisa is a genus of ground beetles in the family Carabidae, subfamily Elaphrinae. It comprises approximately nine extant species distributed across the Holarctic region, plus one fossil species from the Pleistocene. Members of this genus are associated with aquatic or semi-aquatic habitats, with documented diving behavior in at least one species.
Brychius
crawling water beetles
Brychius is a genus of small aquatic beetles in the family Haliplidae, commonly known as crawling water beetles. The genus comprises five recognized species distributed across parts of Europe and North America. One species, Brychius hungerfordi, is federally endangered in the United States. Members of this genus inhabit freshwater environments and are associated with aquatic vegetation.
Brychius hornii
Horn's Crawling Water Beetle
Brychius hornii is a species of crawling water beetle in the family Haliplidae, first described by George Robert Crotch in 1873. It is native to western North America, where adults inhabit small streams and irrigation ditches, primarily on gravel substrates. The species belongs to a small genus of aquatic beetles adapted to life in running water environments.
Buenoa platycnemis
Buenoa platycnemis is a species of backswimmer in the family Notonectidae. It is a predatory aquatic insect found in freshwater habitats across the Americas. The genus Buenoa is distinguished by males producing audible stridulatory sounds, a rare trait among aquatic Heteroptera. This species has been recorded from North, Central, and South America, including multiple states in Brazil.
Carapacea
Carapacea is a suborder of mayflies (Ephemeroptera) characterized by nymphs possessing a distinctive carapace-like structure formed from expanded and fused thoracic tergites. This morphological adaptation distinguishes them from other mayfly suborders. The group includes families such as Baetiscidae and Prosopistomatidae. Carapacean mayflies are primarily found in running water habitats.
Celina
Celina is a genus of small predaceous diving beetles (family Dytiscidae) first described by Aubé in 1837. These aquatic beetles belong to the subfamily Hydroporinae and tribe Methlini. The genus occurs primarily in the Neotropical region, with records from northern South America including Colombia. Members of this genus are aquatic predators inhabiting freshwater environments.
Cenocorixa
water boatmen
Cenocorixa is a genus of water boatmen (family Corixidae) comprising approximately 12 described species. These aquatic insects are notable for their specialized swimming mechanics using synchronized hind leg rowing, and for their complex acoustic communication systems involving species- and sex-specific stridulatory signals. Both males and females produce sound by rubbing specialized pegs on the fore femora against the head. The genus exhibits significant ecological research interest regarding feeding niche partitioning in sympatric and allopatric populations, with some species inhabiting saline lakes.
Centrocorisa nigripennis
Centrocorisa nigripennis is a species of water boatman in the family Corixidae, first described by Fabricius in 1803. It belongs to the suborder Heteroptera (true bugs) within the order Hemiptera. The genus Centrocorisa is part of the tribe Corixini, a group of aquatic insects commonly known as water boatmen. As a member of the Nepomorpha, it is adapted to an aquatic lifestyle. The species has been recorded across the Caribbean, Middle America, and North America.
Chaoboridae
phantom midges, glassworms
Chaoboridae, known as phantom midges or glassworms, is a family of aquatic midges with cosmopolitan distribution. The family comprises approximately 55–90 species across six genera, including the widespread Chaoborus and the endemic Australian genera Promochlonyx and Australomochlonyx. Adults are delicate, chironomid-like flies distinguished by wing venation and plumose male antennae. Larvae are nearly transparent aquatic predators with modified raptorial antennae used to capture prey.
Chaoborus albatus
phantom midge
Chaoborus albatus is a species of phantom midge described by Johnson in 1921. As a member of the family Chaoboridae, it is an aquatic dipteran whose larvae are known for their transparent, nearly invisible bodies. The genus Chaoborus is characterized by larvae that lack respiratory siphons and possess unique gas-filled tracheal sacs that function as hydrostatic organs for vertical migration in water columns.
Chaoborus festivus
phantom midge
Chaoborus festivus is a species of phantom midge in the family Chaoboridae, first described by Dyar and Shannon in 1924. The genus Chaoborus comprises aquatic midges known for their transparent, nearly invisible larvae that inhabit freshwater systems. Larvae are predatory and possess unique gas-filled sacs that aid in buoyancy control. Adults are short-lived and do not feed.
Cirolanidae
Cirolanidae is a family of aquatic isopod crustaceans established by Dana in 1852. The family encompasses approximately 70 genera and over 500 species, ranging from small interstitial forms to the supergiant deep-sea isopods of the genus Bathynomus that can exceed 30 cm in length. Members occupy diverse aquatic habitats including marine coastal waters, deep-sea environments, freshwater systems, and subterranean groundwater. The family is characterized by dorsoventrally flattened bodies and includes both free-living and troglobitic species.
Cleptelmis addenda
Cleptelmis addenda is a species of riffle beetle in the family Elmidae, first described by Fall in 1907. Riffle beetles are aquatic insects adapted to life in fast-flowing streams and rivers. The species is known from North America, though specific details about its biology remain poorly documented.
Clinocerinae
aquatic dance flies
Clinocerinae is a subfamily of dance flies (Empididae) comprising 16 recognized genera including Clinocera, Wiedemannia, Dolichocephala, Trichoclinocera, and Kowarzia. Members are commonly known as aquatic dance flies due to their strong association with freshwater habitats. The subfamily has a global distribution with particularly diverse faunas in the Palaearctic and Oriental regions. Multiple generic revisions and species-level revisions have been published for Nearctic, Palaearctic, and Oriental faunas.
Colymbetes dolabratus
Colymbetes dolabratus is a predaceous diving beetle in the family Dytiscidae. It has a Holarctic distribution, occurring in both North America and the Palearctic region. The species belongs to the genus Colymbetes, a group of medium-sized diving beetles adapted to aquatic habitats.
Colymbetes longulus
Colymbetes longulus is a species of diving beetle in the family Dytiscidae, first described by LeConte in 1862. It belongs to the subfamily Colymbetinae, a group of predatory aquatic beetles. The genus Colymbetes is among the more diverse genera of diving beetles, with species distributed across the Northern Hemisphere. Like other members of its family, this species is adapted to life in freshwater habitats.
Colymbetes sculptilis
Sculptured Predaceous Diving Beetle
Colymbetes sculptilis is a species of predaceous diving beetle in the family Dytiscidae. It is known from North America, with records from Canada (Alberta, British Columbia) and the United States. As a member of the genus Colymbetes, it is adapted to aquatic habitats and exhibits the typical diving beetle morphology of streamlined body form and hind legs modified for swimming. The specific epithet 'sculptilis' refers to the sculptured or carved appearance of the body surface.
Copepoda
copepods
Copepods are small aquatic crustaceans and one of the most abundant and diverse multicellular organisms on Earth. They occupy nearly every aquatic habitat, from marine plankton to deep ocean floors, freshwater lakes, groundwater systems, and even moist terrestrial environments such as leaf litter and bromeliad phytotelmata. The group includes free-living forms as well as highly modified parasites. Copepods are fundamental components of aquatic food webs, serving as critical prey for fish, whales, and other marine life, while also contributing to nutrient cycling and carbon sequestration through the biological pump.
Coptotomus loticus
Coptotomus loticus is a predaceous diving beetle described by Hilsenhoff in 1980. It belongs to the subfamily Coptotominae within Dytiscidae, a family of aquatic beetles. The species is known from eastern Canada, with records from Ontario and Québec. As a member of Coptotomus, it represents one of the less commonly encountered genera in North American dytiscid fauna.
Corixidae
Water Boatmen, Lesser Water Boatmen
Corixidae is a family of aquatic true bugs in the order Hemiptera, commonly known as water boatmen or lesser water boatmen. The family comprises approximately 500 species across 33-55 genera distributed worldwide in freshwater habitats, with a few species inhabiting saline waters. Members are distinguished from similar aquatic bugs by their right-side-up swimming posture, flattened body shape, and modified front legs adapted for feeding. The family exhibits diverse feeding strategies including herbivory, carnivory, detritivory, and omnivory.
Corixinae
water boatman
Corixinae is a subfamily of aquatic true bugs comprising at least 130 described species. Members are commonly known as water boatmen and are found in freshwater habitats worldwide. The subfamily includes the genera Corixa and Sigara, among others. Larvae develop through five instars, with distinct morphometric and chaetotaxy characteristics separating developmental stages.
Crenitis paradigma
Crenitis paradigma is a species of water scavenger beetle in the family Hydrophilidae. It is a small aquatic beetle known from western North America. The species was described by Orchymont in 1942. Like other members of the genus Crenitis, it is associated with aquatic or semi-aquatic habitats.
Crinodessus
Crinodessus is a monotypic genus of predaceous diving beetles in the family Dytiscidae. The genus contains a single species, Crinodessus amyae, described by K.B. Miller in 1997. This genus belongs to the tribe Bidessini within the subfamily Hydroporinae.
Curicta
water scorpion
Curicta is a genus of aquatic insects in the family Nepidae, commonly known as water scorpions. Members of this genus are predatory true bugs found in freshwater habitats. The genus was established by Stål in 1861 and is placed in the tribe Curictini within the subfamily Nepinae. Curicta scorpio is one documented species, with records extending from Central to South America.
Cybister
Giant Diving Beetles
Cybister is a genus of large predaceous diving beetles (Dytiscidae) distributed across all continents except Antarctica. Adults range up to 43 mm in length, with some species among the largest diving beetles. The genus comprises approximately 98 species organized into four subgenera. Both adults and larvae are aquatic predators, with larvae of some species known to prey on vertebrates including tadpoles and small fish.
Cyrtobagous salviniae
salvinia weevil, Kariba Weed Biocontrol Weevil
Cyrtobagous salviniae is a subaquatic weevil native to Brazil, widely distributed as a classical biological control agent for invasive aquatic ferns of the genus Salvinia. It has proven effective in reducing infestations of Salvinia molesta and Salvinia minima in tropical and subtropical regions, with documented population reductions exceeding 90% in under one year in some cases. The species is subject to natural enemy pressure from pathogens such as Helicosporidium sp., which can reduce its reproductive output and efficacy.
Dicranopselaphus
water-penny beetles
Dicranopselaphus is a genus of water-penny beetles in the family Psephenidae, comprising over 40 described species. The genus exhibits a disjunct distribution spanning Asia and North America. Members are aquatic beetles with distinctive flattened, oval larval forms adapted to clinging to submerged surfaces in flowing water.
Dineutus angustus
whirligig beetle
Dineutus angustus is a species of whirligig beetle in the family Gyrinidae, first described by LeConte in 1878. The species is found in North America. As a member of the genus Dineutus, it is among the larger whirligig beetles, characterized by a hidden scutellum and rounded elytral apices. Like other gyrinids, it inhabits the surface of freshwater bodies where it forms aggregations called rafts.
Dineutus ciliatus
whirligig beetle
Dineutus ciliatus is a species of whirligig beetle in the family Gyrinidae. It is one of two genera of whirligig beetles found in Missouri, distinguished from the smaller Gyrinus by its larger size (~12 mm) and hidden scutellum. The species is found in North America and is distinguished from similar congeners primarily by its dark ventral coloration and dark legs, in contrast to the orange-legged D. emarginatus. Whirligig beetles are aquatic insects that live almost exclusively on the water surface, where they form aggregations called 'rafts' that provide anti-predator benefits through increased vigilance and chemical defense.
Dixidae
Meniscus Midges
Dixidae (meniscus midges) are a small family of nematocerous Diptera comprising fewer than 200 species. Adults are small, frail gnats that remain near aquatic habitats and do not feed. Larvae are aquatic filter-feeders that inhabit unpolluted freshwater margins, where they rest in a distinctive U-shaped posture at the water surface film. The family occurs on all continents except Antarctica and has been documented since the Jurassic period.
Dolichopus albiciliatus
Dolichopus albiciliatus is a species of long-legged fly in the family Dolichopodidae, first described by Loew in 1862. Members of the genus Dolichopus are characterized by elongated legs and often metallic coloration. As with other dolichopodids, adults are predatory on small insects.
Dolichopus setifer
Dolichopus setifer is a species of long-legged fly in the family Dolichopodidae, described by Loew in 1861. As a member of the genus Dolichopus, it shares traits with other species in this group, including elongated legs and predatory habits. Adults are typically found in moist habitats near water. The species has been documented in 46 iNaturalist observations, indicating it is encountered with moderate frequency by naturalists.
Dolomedes okefinokensis
Okefenokee Fishing Spider
Dolomedes okefinokensis is a large nursery web spider endemic to the southeastern United States, named for the Okefenokee Swamp. Females reach approximately 30 mm in body length, while males are substantially smaller at about 8 mm. The species is strongly associated with swampy aquatic habitats and is difficult to distinguish from the similar Dolomedes tenebrosus. As a fishing spider, it exhibits surface-dwelling predatory behaviors characteristic of the genus.
Dolomedes vittatus
Banded Fishing Spider
Dolomedes vittatus is a nursery web spider commonly known as the Banded Fishing Spider. It occurs throughout the United States. As a member of the genus Dolomedes, it is associated with aquatic and semi-aquatic habitats where it hunts prey at the water's surface. The species is among the more frequently observed fishing spiders in North America, with over 5,000 documented observations.
Donacia
Donacia is a large genus of aquatic leaf beetles in the subfamily Donaciinae. Adults are active, capable of sustained flight, and possess adaptations for both aerial and submerged existence. The genus is distinguished by a truncate elytral apex and a pubescent area above the procoxa. Larvae develop on submerged portions of aquatic plants, while adults inhabit surface parts of the same host vegetation. The genus contains approximately 113 described species arranged into 15 proposed subgenera, with major radiations in the Nearctic and Palaearctic regions.
Donacia distincta
Donacia distincta is an aquatic leaf beetle in the family Chrysomelidae, described by LeConte in 1851. The species is known from North America, with records from Canada including Alberta, British Columbia, and Labrador. As a member of the subfamily Donaciinae, it shares the characteristic aquatic or semi-aquatic lifestyle of its genus.
Donacia fulgens
Glittering reed beetle
Donacia fulgens, commonly known as the glittering reed beetle, is a species of leaf beetle in the subfamily Donaciinae. Members of this genus are aquatic or semi-aquatic beetles closely associated with emergent vegetation in freshwater habitats. The species was described by LeConte in 1851 and is known to occur in North America, with records from Canada including Manitoba, New Brunswick, and Nova Scotia.
Donacia hypoleuca
Pale pond lily leaf beetle
Donacia hypoleuca is an aquatic leaf beetle in the family Chrysomelidae, commonly known as the pale pond lily leaf beetle. It is found in North America, with records from regions including Québec, Canada. As a member of the genus Donacia, it is associated with aquatic or semi-aquatic habitats and is likely linked to pond lily (Nymphaea) or other aquatic vegetation as host plants.
Donacia liebecki
Donacia liebecki is an aquatic leaf beetle in the family Chrysomelidae, first described by Schaeffer in 1919. The species is known from North America, with records from Saskatchewan, Canada. As a member of the subfamily Donaciinae, it is adapted to aquatic or semi-aquatic habitats. Specific ecological details for this species remain poorly documented in the available literature.
Donacia magnifica
magnificent aquatic leaf beetle, Magnificent pondweed beetle
Donacia magnifica is an aquatic leaf beetle in the family Chrysomelidae, first described by LeConte in 1851. It is native to North America, with records from Canada and the northern United States. The species is closely associated with pondweeds (Potamogeton spp.), on whose leaves adults feed. Like other members of the genus Donacia, it is adapted to an aquatic lifestyle.
Donacia militaris
Well-armed pond lily beetle
Donacia militaris is an aquatic leaf beetle in the family Chrysomelidae. It is native to the eastern United States. Like other members of the genus Donacia, it is associated with aquatic vegetation. The common name "Well-armed pond lily beetle" reflects both its aquatic habitat and the species epithet.
Donacia parvidens
Donacia parvidens is an aquatic leaf beetle in the family Chrysomelidae. The species was described by C. Schaeffer in 1919. It is found in North America, with records from Ontario, Canada. As a member of the subfamily Donaciinae, it is adapted to life in association with aquatic vegetation.
Donacia pubescens
Pubescent sedge beetle
Donacia pubescens is an aquatic leaf beetle in the family Chrysomelidae, first described by LeConte in 1868. It is found across North America, with records from Canada (Alberta, British Columbia, Manitoba) and the United States. Like other members of the genus Donacia, it is associated with aquatic habitats and is likely a specialist on aquatic plants.
Donacia tuberculata
Tuberculate reed beetle
Donacia tuberculata is a species of aquatic leaf beetle in the subfamily Donaciinae. It occurs in North America and is associated with aquatic and semi-aquatic habitats. Like other members of its genus, it is linked to wetland vegetation and has aquatic larvae that develop on submerged plant roots.
Draeculacephala inscripta
Waterlettuce Leafhopper
Draeculacephala inscripta is a leafhopper species in the family Cicadellidae, first described by Van Duzee in 1915. It is commonly known as the Waterlettuce Leafhopper due to its association with aquatic and semi-aquatic host plants. The species has been recorded from multiple U.S. states including Arkansas, Connecticut, Florida, Georgia, and Hawaii, as well as being present in California where it has been studied as a host for egg parasitoids. Its eggs serve as hosts for several parasitoid wasp species in the families Mymaridae and Trichogrammatidae.
Dromogomphus
Spinylegs, Spiny-legged Clubtails
Dromogomphus is a genus of dragonflies in the family Gomphidae, commonly known as spinylegs. The common name refers to the prominent spines on their legs, which function in prey capture. The genus includes three North American species: southeastern spinyleg, black-shouldered spinyleg, and flag-tailed spinyleg. These dragonflies are medium to large-sized clubtails with distinctive morphological features.
Drosophila deflecta
Drosophila deflecta is a fruit fly species in the Drosophila quinaria species group, first described by Malloch & McAtee in 1924. The species is notable for its specialized larval ecology: larvae function as scavengers on Nuphar water lilies. Unlike the well-studied invasive relative Drosophila suzukii, D. deflecta has received limited research attention and is known from few observations.