The downy emerald (''Cordulia aenea'') is a species of
dragonfly. It is metallic green and bronze in color, and its
thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
is coated with fine hairs, hence its name. Like most other
emeralds
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium.Hurlbut, Cornelius S. Jr. and Kammerling, Robert C. (1991) ''Gemology'', John Wiley & Sons, New York, p. ...
, the downy emerald has bright shiny green eyes. Adults are around 5 cm in length, and are in flight from May through July each year.
This species lives in
woodland
A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (se ...
s near lakes and ponds; like other dragonflies, it lays eggs in water and its larvae are aquatic. It is distributed throughout most of Europe. Although it has been eliminated from some of its historic native area in
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It i ...
due to habitat loss, dense populations of the downy emerald can still be found there in spots where its ideal habitat remains.
After the downy emerald young emerge from their eggs, they live for three years at various larval and nymphal stages. They are fully grown adults for only two months, during which time they mate and the females deposit their eggs back into the water. Female individuals of the ''Cordulia aenea'' (''C. aenea'') species have panoistic ovaries that produce female sex cells, or oocytes. The nucleus of the panoistic oocyte likely contains all the necessary genetic material to develop the oocyte on its own, form the ''C. aenea'' egg yolk, and develop the ''C. aenea'' embryo.
References
External links
Downy Emeraldpictures in nature photographer Janne Heimonen's photo gallery
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Corduliidae
Dragonflies of Europe
Insects described in 1758
Taxa named by Carl Linnaeus
{{Corduliidae-stub