Sussex Dragonfly Group

Keeled Skimmer (Keeled Orthetrum)
Orthetrum coerulescens (Fabricius, 1798)
« Orthetrum cancellatum | Oxygastra curtisii »

Suborder: Anisoptera
Family: Libellulidae

Keeled Skimmer
(Keeled Orthetrum)
Orthetrum coerulescens

Suborder: Anisoptera
Family: Libellulidae

In Sussex this species is at the extreme eastern edge of its range, occurring at a few heathland pools. It is a darter-sized dragonfly, with a slim tapering abdomen. The all-blue abdomen of the mature male has a pronounced ‘keel’, especially when viewed from the side. The female has a golden-brown abdomen, which darkens with age with a thin black stripe along the top.

Orthetrum coerulescens
1 / 8
male
Photo: Simon Linington
Orthetrum coerulescens
2 / 8
immature male
Photo: David Sadler
Orthetrum coerulescens
3 / 8
young male
Photo: Simon Linington
Orthetrum coerulescens
4 / 8
ovipositing female
Photo: David Sadler
Orthetrum coerulescens
5 / 8
female
Photo: David Sadler
Orthetrum coerulescens
6 / 8
male
Photo: Simon Linington
Orthetrum coerulescens
7 / 8
male
Photo: Simon Linington
Orthetrum coerulescens
8 / 8
mating
Photo: David Sadler

More images

National status
Locally common, with a patchy distribution mainly in western Britain.

Status in Sussex
Rare, with only 12 pre-1990 records. Ashdown Forest is the only relatively secure locality in Sussex. Listed in the Sussex Rare Species Inventory.

Distribution at 1km scale

Orthetrum coerulescens distribution (all)
Orthetrum coerulescens distribution pre 1980
Orthetrum coerulescens distribution 1980 - 1989
Orthetrum coerulescens distribution 1990 - 1999
Orthetrum coerulescens distribution 2000 - 2009
Orthetrum coerulescens distribution 2010 - 2019
Orthetrum coerulescens distribution 2010 on

Historical records
The third species first recorded in Sussex near Tunbridge Wells in August 1908 by E. Speyer (Bloomfield 1910), it was also found at Amberley Wildbrooks by Guermonprez on 10 August 1909 (Dannreuther 1945). Chelmick (1979) wrote that “This rare species, with the exception of Lestes dryas, has declined more than any other in recent years” and that there was just one locality for it at the time (east of Crowborough). On Ashdown Forest Fowles (1985) did not record it, but Marrable (1999) found it at two sites, and the survey for The Dragonflies of Sussex (2004) did in six 1x1 kilometre squares.

Flight times
Late June - early September.

Phenology (adult)

Orthetrum coerulescens phenology (all)
Orthetrum coerulescens phenology pre 1980
Orthetrum coerulescens phenology 1980 - 1989
Orthetrum coerulescens phenology 1990 - 1999
Orthetrum coerulescens phenology 2000 - 2009
Orthetrum coerulescens phenology 2010 - 2019
Orthetrum coerulescens phenology 2010 on
Orthetrum coerulescens habitat
1 / 1
Keeled Skimmer habitat at Old Lodge, Ashdown Forest (drought affected pond in Aug 2020)
Photo: Simon Linington

Habitat
Acid pools, streams and ditches in wet heath areas, usually where Sphagnum moss is present.

Conservation
The conservation, restoration or creation of small bog ponds on our wet heaths, a priority habitat, could help expand the range and number of sites for this species. The British Dragonfly Society website lists the main threats as erratic rainfall due to climate change, pollution and both abstraction and drainage.

Similar species
See Scarce Chaser for discussion on the identification of this species from the Chasers and from Black-tailed Skimmer (a photographic comparison is provided).

In Sussex this species is at the extreme eastern edge of its range, occurring at a few heathland pools. It is a darter-sized dragonfly, with a slim tapering abdomen. The all-blue abdomen of the mature male has a pronounced ‘keel’, especially when viewed from the side. The female has a golden-brown abdomen, which darkens with age with a thin black stripe along the top.

Orthetrum coerulescens
1 / 8
male
Photo: Simon Linington
Orthetrum coerulescens
2 / 8
immature male
Photo: David Sadler
Orthetrum coerulescens
3 / 8
young male
Photo: Simon Linington
Orthetrum coerulescens
4 / 8
ovipositing female
Photo: David Sadler
Orthetrum coerulescens
5 / 8
female
Photo: David Sadler
Orthetrum coerulescens
6 / 8
male
Photo: Simon Linington
Orthetrum coerulescens
7 / 8
male
Photo: Simon Linington
Orthetrum coerulescens
8 / 8
mating
Photo: David Sadler

National status
Locally common, with a patchy distribution mainly in western Britain.

Status in Sussex
Rare, with only 12 pre-1990 records. Ashdown Forest is the only relatively secure locality in Sussex. Listed in the Sussex Rare Species Inventory.

Distribution at 1km scale

Orthetrum coerulescens distribution (all)
Orthetrum coerulescens distribution bre 1980
Orthetrum coerulescens distribution 1980 - 1989
Orthetrum coerulescens distribution 1990 - 1999
Orthetrum coerulescens distribution 2000 - 2009
Orthetrum coerulescens distribution 2010 - 2019
Orthetrum coerulescens distribution 2020 on

Historical records
The third species first recorded in Sussex near Tunbridge Wells in August 1908 by E. Speyer (Bloomfield 1910), it was also found at Amberley Wildbrooks by Guermonprez on 10 August 1909 (Dannreuther 1945). Chelmick (1979) wrote that “This rare species, with the exception of Lestes dryas, has declined more than any other in recent years” and that there was just one locality for it at the time (east of Crowborough). On Ashdown Forest Fowles (1985) did not record it, but Marrable (1999) found it at two sites, and the survey for The Dragonflies of Sussex (2004) did in six 1x1 kilometre squares.

Flight times
Late June - early September.

Phenology (adult)

Orthetrum coerulescens phenology (all)
Orthetrum coerulescens phenology pre 1980
Orthetrum coerulescens phenology 1980 - 1989
Orthetrum coerulescens phenology 1990 - 1999
Orthetrum coerulescens phenology 2000 - 2009
Orthetrum coerulescens phenology 2010 - 2019
Orthetrum coerulescens phenology 2020 on
Orthetrum coerulescens habitat
1 / 1
Keeled Skimmer habitat at Old Lodge, Ashdown Forest (drought affected pond in Aug 2020)
Photo: Simon Linington

Habitat
Acid pools, streams and ditches in wet heath areas, usually where Sphagnum moss is present.

Conservation
The conservation, restoration or creation of small bog ponds on our wet heaths, a priority habitat, could help expand the range and number of sites for this species. The British Dragonfly Society website lists the main threats as erratic rainfall due to climate change, pollution and both abstraction and drainage.

Similar species
See Scarce Chaser for discussion on the identification of this species from the Chasers and from Black-tailed Skimmer (a photographic comparison is provided).