Cordulegaster bidentata explained

Cordulegaster bidentata, also known as sombre goldenring or two-toothed goldenring, is a species of dragonfly in the family Cordulegastridae.

Description

This species is identifiable by its black body and yellow rings.^[1] Adults are approximately 8cm (03inches) in body length with a 10cm (00inches) wingspan, and have a similar appearance to the related species Cordulegaster boltonii.^[2]

Distribution and habitat

C. bidentata is primarily found in Central and Southern Europe,^[3] spreading as far south as Sicily, where the subspecies C. bidentata sicilica is found. It lives primarily around mountain springs.^[4] This species is scattered throughout Central and Western Europe. The population rate is declining, the biggest threat to this species being droughts which are a result of global warming.^[5]

Behaviour and development

C. bidentata breeds in mountain springs, and the larvae are benthic, living in the lowest reaches of the water.^[6] As a result of this, larval sites are difficult to locate and study. Breeding takes place in May–June, with eggs being laid in the upper reaches of the streams. Larval development takes between three and five years, and can be slowed if cold weather causes the water to freeze.^[2] The larvae may sometimes leave the water, hunting for small arthropods on the ground at night.^[7]

Notes and References

1. Web site: Sombre goldenring (Cordulegaster bidentata). Arkive.org. 17 October 2014. https://web.archive.org/web/20141024220958/http://www.arkive.org/sombre-goldenring/cordulegaster-bidentata/. 2014-10-24. dead.
2. Web site: Cordulegaster bidentata. Odonata on stamps. 17 October 2014.
3. Web site: Sombre Goldenring (Cordulegaster bidentata). Dragonflypix. 17 October 2014. https://web.archive.org/web/20141023183928/http://www.dragonflypix.com/speciespages/cordulegaster_bidentata.html. 23 October 2014. dead.
4. Brunke. Matthew. Patchiness of River: Groundwater Interactions within Two Floodplain Landscapes and Diversity of Aquatic Invertebrate Communities. Ecosystems. Dec 2003. 6. 8. 713. 3658648. 10.1007/pl00021501. 23856797 .
5. Web site: Cordulegaster bidentata. ICUN redlist. ICUN. 17 October 2014.
6. Book: Victor Fet. Alexi Popov. Biogeography and Ecology of Bulgaria. 21 June 2007. Springer Science & Business Media. 978-1-4020-4417-5. 224.
7. Book: Ecology and general biology. Thorp and Covich's Freshwater Invertebrates . 4 . Academic Press . Thorp . James . Rogers . D. Christopher . 9780123850263 . Suhling, F. . Sahlén, G. . Gorb, S. . Kalkman, V.J. . Dijkstra, K.-D.B. . van Tol, J. . 2015 . Order Odonata . 893–932.