''Hydrometra gracilenta'', the lesser water-measurer, is a species of aquatic

bugs Bugs may refer to: * Plural of bug Arts, entertainment and media Fictional characters * Bugs Bunny, a character * Bugs Meany, a character in the ''Encyclopedia Brown'' books Films * ''Bugs'' (2003 film), a science-fiction-horror film * ''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 ...

Description

''Hydrometra gracilenta'' is long, somewhat smaller than ''

Hydrometra stagnorum ''Hydrometra stagnorum'', the common water-measurer, is a species of aquatic bugs in the family Hydrometridae, the ''water measurers''. Distribution This species is found in numerous European countries, including Hungary and Austria. In Great ...

''; its eyes are located halfway down its head. Its specific name is from the Latin word for "slender."

Habitat

This species lives in ponds in

Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe Northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other g ...

(including Great Britain and Ireland) and Italy. It is on the United Kingdom Biodiversity Action Plan (UKBAP) list, preferring well-vegetated ditches flooded, or surface wet fen (marsh) with dense vegetation.

Behaviour

It is diurnal and eats other insects, including Chironomidae (non-biting midges). The female lays her

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s in May or June; they develop into nymphs and then become adults by July. The name "water measurer" refers to the insects' habit of walking on the surface of ditches and ponds, apparently pacing the distances between points. Hydrophobic hairs on its legs allow it to walk on the surface of the water.

References

External links

Distribution map in Ireland
* Hydrometroidea Hemiptera of Europe Taxa named by Géza Horváth Insects described in 1899 {{Gerromorpha-stub