Sailing Bluet (Azuragrion nigridorsum)

The photo above (by Bernardine Altenroxel) can be viewed in OdonataMAP here.

Azuragrion nigridorsum, the Sailing Bluet or Black-tailed Bluet, is a species of damselfly in the family Coenagrionidae.

Identification

Very small size

Length up to 28mm; Wingspan attains 33mm.

Often found alongside the Africallagma glaucum, but is easily differentiated by its deeper blue colour and black protrusion onto the eighth segment of the abdomen.

The females are similar to other Bluet females, and are best identified by their association with the males.

Azuragrion nigridorsum – Near Hluhluwe, KwaZulu-Natal
Photo by Ryan Tippett

Habitat

A species of well vegetated, still water environments such as dams, ponds, marshes, pools and the quiet backwaters of rivers and streams. Azuragrion nigridorsum usually occupies areas with floating and emergent plants like waterlilies and sedges and is frequently found near floating mats of green algae.

Typical habitat – Near Hluhluwe, KwaZulu-Natal
Photo by Ryan Tippett

Behaviour

Mostly found low down close to the water where it perches on lily pads or emergent plants. The flight is fast and typically low over the water. When the weather is calm they sometimes land gently on the water without breaking the surface. They then drift across the pond in the breeze with their folded wings acting as sails. The females are often found in the same vicinity as the males.

Status and Conservation

The sailing Bluet is a common and widespread species. It is listed as of Least Concern in the IUCN Red List of Threatened Species. Azuragrion nigridorsum is moderately sensitive to habitat damage, but has adapted well to man-made habitats and has doubtless benefited from this.

Distribution

Azuragrion nigridorsum is found from Ethiopia in the north, down through most of East and Southern Africa, including Angola and Zambia. In South Africa it is mostly absent from the dry central region.

Below is a map showing the distribution of records for Sailing Bluet in South Africa. Taken from the OdonataMAP database as at February 2020.

The next map below is an imputed map, produced by an interpolation algorithm, which attempts to generate a full distribution map from the partial information in the map above. This map will be improved by the submission of records to the OdonataMAP section of the Virtual Museum.

Ultimately, we will produce a series of maps for all the odonata species in the region. The current algorithm is a new algorithm. The objective is mainly to produce “smoothed” maps that could go into a field guide for odonata. This basic version of the algorithm (as mapped above) does not make use of “explanatory variables” (e.g. altitude, terrain roughness, presence of freshwater — we will be producing maps that take these variables into account soon). Currently, it only makes use of the OdonataMAP records for the species being mapped, as well as all the other records of all other species. The basic maps are “optimistic” and will generally show ranges to be larger than what they probably are.

These maps use the data in the OdonataMAP section of the Virtual Museum, and also the database assembled by the previous JRS funded project, which was led by Professor Michael Samways and Dr KD Dijkstra.

Sailing Bluet OdonataMAP record by Felicity Grundlingh
Dragonfly Atlas: Megan Loftie-Eaton, Sally Hofmeyr, Ryan Tippett & Les Underhill
Dragonfly Atlas: Megan Loftie-Eaton, Sally Hofmeyr, Ryan Tippett & Les Underhill
Megan Loftie-Eaton is our communications, social media and citizen science coordinator. Prior to her work for the BDI, she coordinated OdonataMAP, the Atlas of African Odonata. Sally Hofmeyr has many years' experience in the academic world, writing her own material and editing the work of others. Her academic background is in the natural sciences: her PhD and first postdoc in ornithology and environmental change (Animal Demography Unit, University of Cape Town). Ryan Tippett is an enthusiastic contributor to Citizen Science and has added many important and interesting records of fauna and flora. He has been a member of the VMU since 2014 and has currently submitted over 11000 records. He is also on the expert identification panel for the Odonata Map project. Prof Les Underhill has been Director of the Animal Demography Unit (ADU) at the University of Cape Town since it started in 1991. Although citizen science in biology is Les’s passion, his academic background is in mathematical statistics.