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Family: Elmidae View: lateral
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Family: Elmidae View: lateral
Updated: October 09, 2013 
Aquatic species occur in two major suborders, the Adephaga and the Polyphaga. Both larvae and adults of six beetle families are aquatic, Dytiscidae (predaceous diving beetles), Elmidae (riffle beetles), Gyrinidae (whirligig beetles), Haliplidae (crawling water beetles), Hydrophilidae (water scavenger beetles), and Noteridae (burrowing water beetles). Five families, Chrysomelidae (leaf beetles), Limnichidae (marsh-loving beetles), Psephenidae (water pennies), Ptilodactylidae (toe-winged beetles), and Scirtidae (marsh beetles) have aquatic larvae and terrestrial adults, as do most of the other orders of aquatic insects; adult limnichids, however, readily submerge when disturbed. Three families have species that are terrestrial as larvae and aquatic as adults, Curculionidae (weevils), Dryopidae (long-toed water beetles), and Hydraenidae (moss beetles), a highly unusual combination among insects.
Many other beetle families have species that are riparian, semiaquatic, coastal, or marine. Because beetles exhibit such diverse adaptations, generalisations about life history patterns and feeding are difficult at the ordinal or even subordinal level.
Unlike the Hemiptera, the larvae of Coleoptera are morphologically and behaviourally different from the adults, and their diversity is high. In temperate regions, beetles from most major groups commonly exhibit univoltine life cycles. However, multivoltinism is, as might be expected, more common in the more stable tropics.
A particularly interesting suite of aquatic and semiaquatic habitats inhabited by beetles occurs at the edge of the sea. In general, insects have not made major inroads into salt water, but a considerable number of beetles are able to tolerate such environmental conditions by either physiological tolerance or behavioural adaptation.
The Coleoptera are divided into four suborders. The first two are very small relict groups, of which the Myxophaga are more or less aquatic, mainly in running water. The Adephaga or carnivorous beetles are a large suborder containing six aquatic families. In the very primitive Amphizoidae, nearly all the Dytiscidae, and the Noteridae, the larvae are metapneustic, breathing by means of a single pair of abdominal spiracles. In the primitive Hydrobiidae, the Haliplidae, one genus of Dytiscidae, and the Gyrinidae, the larvae have tracheal gills.
The Gyrinidae, or whirligig beetles, occur on the surface of ponds in aggregations of up to thousands of individuals. Unlike the mating swarms of mayflies and hemipterans, these aggregations serve primarily to confuse predators. Whirligig beetles have other interesting defensive adaptations. For example, the Johnston's organ at the base of the antennae enables them to echolocate using surface wave signals; their compound eyes are divided into two pairs, one above and one below the water surface, enabling them to detect both aerial and aquatic predators; and they produce noxious chemicals that are highly effective at deterring predatory fish.
| Family | Distribution & Habitat |
|---|---|
| Suborder - Archostemata (none) | |
| Suborder - Myxophaga | |
| Superfamily Sphaerioidea | |
| Sphaeriidae | (minute bog beetles)- edges of freshwater bodies, in roots, mud & gravel |
| Hydroscaphidae | (skiff beetles)- stream margins, often in algae; hot springs |
| Suborder - Adephaga | |
| Superfamily Caraboidea | |
| Carabidae | (ground beetles)- a few species found at the edges of streams, ponds, swamps; rock crevices on seashores |
| Haliplidae | (crawling water beetles)- aquatic vegetation at the edges of ponds, lakes & slow streams |
| Hygrobiidae | standing, often stagnant, muddy water |
| Amphizoidae | (trout stream beetles)- fast streams, often on logs |
| Noteridae | (burrowing water beetles) shallow margins of standing or slow streams, often in mud or on plants |
| Dytiscidae | (predaceous diving beetles)- ponds & lakes, esp. near vegetation; slower sections of running waters |
| Gyrinidae | (whirligig beetles)- ponds & lakes, especially near vegetation; slower sections of streams & rivers |
| Suborder - Polyphaga | |
| Superfamily Hydrophiloidea | |
| Hydraenidae | (moss beetles)- stream margins, ponds near emergent vegetation; hygropetric (wet rock surface) habitats; marine rockpools & intertidal |
| Hydrochidae | (water scavenger beetles)- on plants in ponds or slow streams |
| Spercheidae | (water scavenger beetles)- stagnant ponds on underside of surface film |
| Georyssidae | (minute mud-loving beetles)- margins of freshwater bodies in sand or mud |
| Hydrophilidae | (water scavenger beetles)- ponds & lakes, esp. near vegetation; slower sections of streams & rivers |
| Superfamily Histeroidea | |
| Histeridae | (hister beetles)- some in ponds, also in damp soil & dung |
| Superfamily Staphylinoidea | |
| Staphylinidae | (rove beetles)- some species on the shorelines of fresh and saltwater bodies; marine crevices & intertidal (sand & rocky areas) |
| Superfamily Scaraboidea | |
| some groups appear to need very moist environments, e.g. Lucanidae, Passalidae & Rutelinae (Scarabeidae) | |
| Superfamily Dascilloidea | |
| Helodidae (Scirtidae) | (marsh beetles)- lentic & slow lotic waters, esp. near emergent vegetation; tree holes; springs |
| Superfamily Dryopoidea | |
| Limnichidae | (marsh-loving beetles)- in mud on the margins of streams and ponds |
| Psephenidae | (water pennies)- fast streams, wave-swept shores of large lakes |
| Ptilodactylidae | (toed-winged beetles)- fast & slow water regions of streams; stream margins in leaf litter |
| Heteroceridae | (mud-loving beetles)- tunnels in stiff mud of some stream & pond margins |
| Elmidae | (riffle beetles)- fast & slower sections of streams, wave-swept shores of large lakes; some species on shoreline |
| Dryopidae | (long-toed water beetles)- shallow regions of ponds & lakes esp. in emergent vegetation; swift streams |
| Superfamily Cantharoidea | |
| Melyridae | (flower beetles)- semiaquatic on marine beaches & intertidal zone |
| Superfamily Cucujoidea | |
| Salpingidae | (narrow-waisted bark beetles)- marine, on rocks |
| Superfamily Tenebrionoidea | |
| Tenebrionidae | (darkling beetles)- some species in moist sand on beaches at the high tide mark |
| Anthicidae | (ant-like flower beetles)- some species live in the stream-side burrows of staphylinids; salt marshes |
| Superfamily Chrysomeloidea | |
| Chrysomelidae | (leaf beetles)- ponds & lakes on submerged but esp. floating leaves of rooted macrophytes |
| Superfamily Curculionoidea | |
| Curculionidae | (weevils)- some species of Erirrhininae (e.g. Bagous) live on submerged aquatic plants |
Family Elmidae (Riffle Beetle)
Both adults and larvae are commonly encountered. Adults are considered better indicators of water quality because they have been subjected to water quality conditions over a longer period. (Kellogg, 1994)
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