Lotic-habitat
Guides
Amphizoa striata
trout-stream beetle
Amphizoa striata is a species of trout-stream beetle in the family Amphizoidae, found in western North America. It measures 13–15 millimeters in length and possesses distinctive morphological features on its front tarsi, including a well-developed groove on the posterior surface and grooves bearing long hair-like setae. The species inhabits cold, fast-flowing streams in the Pacific Northwest.
Corydalus
dobsonflies, hellgrammites (larvae), go-devil, grampus
Corydalus is a genus of large flying insects in the family Corydalidae, commonly known as dobsonflies. The genus contains approximately 35 species endemic to North, Central, and South America. Adults are among the largest winged insects in their range, with wing lengths reaching up to 85 millimetres. The genus exhibits pronounced sexual dimorphism: males possess greatly elongated, sickle-shaped mandibles used in male-male combat and to grasp females during mating, while females have smaller but still formidable jaws capable of delivering a painful bite. The aquatic larvae, known as hellgrammites, are predatory and serve as important indicators of stream health.
Cylloepus parkeri
Parker's cylloepus riffle beetle
Cylloepus parkeri is a species of riffle beetle in the family Elmidae, described by Sanderson in 1953. It is known from North America and belongs to a group of beetles specialized for living in fast-flowing aquatic environments. The species epithet honors an individual with the surname Parker.
Erpetogomphus
ringtails
Erpetogomphus is a genus of dragonflies in the family Gomphidae, commonly known as ringtails. The genus comprises approximately 25 extant species distributed primarily in the Americas, plus one fossil species from Early Miocene Mexican amber. Most species exhibit predominantly green coloration, and males possess a moderately clubbed abdomen tip. The genus was taxonomically revised by Rosser Garrison in 1994.
Gammarus pseudolimnaeus
Northern Spring Amphipod
Gammarus pseudolimnaeus is a freshwater amphipod crustacean inhabiting lotic (flowing water) environments in North America. The species exhibits complex behavioral ecology, including size-selective predation vulnerability to fish predators such as brook trout and sculpins, and chemically-mediated responses to predation risk that influence reproductive behavior. Population dynamics are characterized by univoltine (single annual) generation cycles with high mortality during early life stages and winter periods. The species serves as an important prey item in stream food webs and has been extensively studied as a model organism for freshwater invertebrate ecology, toxicology, and predator-prey interactions.
Helichus striatus
long-toed water beetle
Helichus striatus is a species of long-toed water beetle in the family Dryopidae. It inhabits cool, flowing water environments where it occurs on debris and beneath rocks. The species has a broad North American distribution spanning from eastern Canada to the Pacific coast. Two subspecies are recognized: Helichus striatus striatus and Helichus striatus foveatus.
Hesperagrion heterodoxum
Painted Damsel
Hesperagrion heterodoxum, commonly known as the Painted Damsel, is a small damselfly in the family Coenagrionidae. Males are notably colorful, with spectacular coloration that distinguishes them from other damselflies in their range. The species occurs in western North America and Middle America, where it inhabits streams and rivers with emergent vegetation. It has been observed in association with warm springs and vegetated waterways.
Hetaerina americana
American rubyspot
A damselfly species in the family Calopterygidae, commonly known as the American rubyspot. Males exhibit a lustrous red head and thorax with a brilliant green abdomen; females have a green abdomen with either green or copper thoracic markings. The species occupies riverine habitats in arid and semi-arid regions and demonstrates strong site fidelity, with adults rarely dispersing more than 100 meters from emergence sites. Research indicates sensitivity to urbanization, with documented declines in abundance, body condition, and reproductive success correlated with reduced riparian vegetation and increased wastewater discharge.
Heterlimnius corpulentus
Corpulent Riffle Beetle
Heterlimnius corpulentus is a species of riffle beetle in the family Elmidae, commonly known as the Corpulent Riffle Beetle. It was described by LeConte in 1874 and is found in western North America, with records from the Canadian provinces of Alberta and British Columbia. Riffle beetles in this family are aquatic and associated with flowing water habitats.
Hylogomphus
clubtails
Hylogomphus is a genus of clubtail dragonflies (family Gomphidae) comprising six described species native to eastern North America. The genus was elevated from subgenus status within Gomphus in 2000, reflecting distinct morphological and phylogenetic characteristics. Species within this genus are associated with lotic freshwater habitats and exhibit conservative body plans typical of gomphid dragonflies.
Metrobates anomalus
Metrobates anomalus is a water strider species in the family Gerridae, described by Hussey in 1948. It belongs to the genus Metrobates, a group of semiaquatic bugs known for their ability to walk on water surfaces using hydrophobic leg adaptations. The species is part of the subfamily Trepobatinae and tribe Metrobatini, which are primarily associated with running water habitats. Very little specific biological information is documented for this particular species.
Nixe
Nixe is a genus of mayflies in the family Heptageniidae, established by Flowers in 1980. These aquatic insects belong to the order Ephemeroptera, characterized by their short adult lifespan and complex life cycles involving aquatic nymphal stages. The genus has been documented in 451 iNaturalist observations, indicating moderate levels of citizen science engagement. As heptageniid mayflies, members of this genus likely inhabit flowing water environments where their nymphs develop.
Optioservus browni
Brown's optioservus riffle beetle
Optioservus browni is a species of riffle beetle (family Elmidae) described by White in 1978. The species is known from North America and is part of a genus of aquatic beetles typically found in flowing water habitats. Like other elmid beetles, it is adapted to life in fast-moving streams and rivers.
Stenelmis cheryl
Cheryl's Riffle Beetle
Stenelmis cheryl, commonly known as Cheryl's riffle beetle, is a species of riffle beetle in the family Elmidae. The species was described by Brown in 1987. Riffle beetles are aquatic insects typically associated with flowing water habitats. Stenelmis cheryl has been documented in Central America and North America based on occurrence records.
Stenelmis sexlineata
riffle beetle
Stenelmis sexlineata is a riffle beetle in the family Elmidae, described by Sanderson in 1938. It inhabits flowing water environments in North America and has a multi-year life cycle with distinct larval stages. Like other elmid beetles, it is adapted to life in fast-moving streams and rivers.