| Helophorus | |
|---|---|
 | |
| Helophorus aquaticus | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Suborder: | Polyphaga |
| Infraorder: | Staphyliniformia |
| Superfamily: | Hydrophiloidea |
| Family: | Helophoridae Leach, 1815 |
| Genus: | Helophorus Fabricius, 1775 |
| Species | |
see text | |
Helophorus is the only genus in thebeetle familyHelophoridae (traditionally included withinHydrophilidae as the subfamily Helophorinae) within theHydrophiloidea. They are small insects, found mainly in theHolarctic region (150 occur inPalearctic and 41 species inNorth America), but two or three species also live in theAfrotropical region,Central America and one in theIndomalayan region (northern India).[1][2]
Length about 2–9 mm. Body elongate with outline more or less interrupted betweenpronotum andelytra. On pronotum they have granulate sculpture and unique pattern of 7 longitudinal grooves. Ventral surface is with fine microsculpture, pubescent. Larvae are with long 3 segmentedurogomphi and simple (non lobate) 8th tergum. They have four-segmented legs and a 10 segmented abdomen (with the 10th segment being a bit reduced).[3]
The majority ofHelophorus species adults are aquatic live on the periphery of rivers and streams as well as stagnant bodies of water or pools, though a number are also terrestrial. Adults generally feed on decaying plant material, though some are known to feed on living plant tissue, with several species noted as pests ofturnips. The larvae are terrestrial and are predominantly carnivores, though in some species are herviorous, and are pests of turnips,rutabaga, andwheat.[4]
Helophoridae belong to the superfamilyHydrophiloidea, and may be the sister taxon ofHydrochidae,[5] or a clade comprisingHydrochidae,Hydrophilidae andSpercheidae orGeorissidae andEpimetopidae.[6] Earlier systems included all of these families in the family Hydrophilidae. The genus is divided into many subgenera (Atracthelophorus,Cyphelophorus,Empleurus,Eutrichelophorus,Gephelophorus,Helophorus,Orphelophorus,Rhopalohelophorus andTransithelophorus).The oldest fossils ofHelophorus are from the Late Jurassic of Asia, with the major clades of extantHelophorus likely diverging from each other during the Early Cretaceous.[7]
There are about 180 living species, including: