''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