Italian goldenring  (Cordulegaster trinacriae)

Dorsal view of a male Italian goldenring

Facts

Kingdom Animalia
Phylum Arthropoda
Class Insecta
Order Odonata
Family Cordulegastridae
Genus Cordulegaster (1)
Size Male length: 73 - 79 mm (2)
Female length: 83 - 93 mm (2)
Male length of abdomen: 55 - 63 mm (2)
Female length of abdomen: 64 - 72 mm (2)
Male hindwing: 45 - 49 mm (2)
Female hindwing: 51 - 53 mm (2)

Status

Classified as Vulnerable (VU) on the IUCN Red List 2006 (1).

Description

Also referred to as spiketails and biddies, golden-ringed dragonflies (Cordulegastridae) are large black dragonflies with generally bright yellow rings more or less encircling their abdomen, depending on the species (2) (3). The Italian goldenring shows rather small abdominal yellow marks, possesses conspicuous yellow markings on its thorax and head, and has large green eyes. Males and females are similar in appearance, but females are distinctly larger. Separation from the widespread European C. boltonni is mainly possible through the structure of the abdominal appendages of the male (2).

Range

Endemic to southern Italy, including Sicily (1).

Habitat

Found along mountain brooks (1).

Biology

Virtually nothing has been recorded of the Italian goldenring's biology and behaviour, but this may be inferred from what is known about its nearest relative, C. boltonni. The eggs hatch three to six weeks after egg deposition and the larval period should last two to three years, perhaps more in altitude. It should include 12 to 14 stadia. After metamorphosis and emergence, adults, which are, like other Odonata species, generalised, opportunistic feeders, feed on flying insects. Males don't establish territories but patrol over long distances along river edges, searching for reproductive females, and stand quite often on herbs or branches exposed to the sun. They continuously change their route in the course of the day. Females are generally hidden and are much more scarcely observed than males. They lay by driving their eggs in the sandy sediments of rivers and brooks through a rhythmic vertical flight, distinctive of golden-ringed dragonflies (4).

Threats

This dragonfly's severely fragmented population is believed to be declining due to habitat destruction through ongoing deforestation and water extraction for human use (1).

Conservation

There are currently no conservation measures targeting this species, but there is a need to preserve forests and control the levels of water use and harvesting (1).

Authentication

Authenticated (18/12/2006) by Jean-Pierre Boudot, CNRS, Université Henri Poincaré Nancy I, France.

Endemic: A species or taxonomic group that is only found in one particular country or geographic area.
Larvae: Stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but are unable to reproduce.
Metamorphosis: An abrupt physical change from the larval to the adult form.
Thorax: Part of the body located near the head in animals. In insects, the three segments between the head and the abdomen, each of which has a pair of legs.

References

  1. IUCN Red List (May, 2006)
    http://www.iucnredlist.org
  2. Dijkstra, K.D.B. and Lewington, R. (2006) Field Guide to the Dragonflies of Britain and Europe. British Wildlife Publishing, Gillingham.
  3. Dragonflies and Damselflies in Languedoc (September, 2006)
    http://www.ghmahoney.org.uk/insects/dflyl_corga.htm
  4. Grand, D. and Boudot, J.P. (2006) Les Libellules de France, Belgique et Luxembourg. Editions Parthénope, Mèze.