''Hydrometra stagnorum'', the common water-measurer, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of aquatic bugs in the family

Hydrometridae Hydrometridae is a family of semiaquatic insects, known as ''marsh treaders'' or ''water measurers''. They have a characteristic elongated head and body which makes them resemble a yardstick for measuring the water surface. Appearance Hydrometri ...

, the ''water measurers''.

Distribution

This species is found in numerous European countries, including Hungary and Austria. In Great Britain it is quite common in

Leicestershire Leicestershire ( ; postal abbreviation Leics.) is a ceremonial and non-metropolitan county in the East Midlands, England. The county borders Nottinghamshire to the north, Lincolnshire to the north-east, Rutland to the east, Northamptonshire t ...

and

Rutland Rutland () is a ceremonial county and unitary authority in the East Midlands, England. The county is bounded to the west and north by Leicestershire, to the northeast by Lincolnshire and the southeast by Northamptonshire. Its greatest len ...

Description

''Hydrometra stagnorum'' is normally wingless, but sometimes has full wings. It is often dark greyish or even black in colour, and grows to approximately 13mm. The head and body are long and thin. Its antennae appear similar to a fourth pair of legs.

Habitat

This species lives at the vegetated margins in slow moving streams, as well as ditches and ponds. It lives close to the emergent stems of plants, upon which it lays its eggs.

Behaviour

As adults, rows slowly over the surface of the water in search of prey. It seeks mosquito larvae and water fleas directly below the surface film. It catches these by spearing them through the surface of the water. This species can jump if disturbed.

References

External links

Distribution map in England

Hydrometroidea Articles containing video clips Hemiptera of Europe Taxa named by Carl Linnaeus Bugs described in 1758 {{Gerromorpha-stub